Sample records for required log reduction
-
Estimation of norovirus infection risks to consumers of wastewater-irrigated food crops eaten raw.
Mara, Duncan; Sleigh, Andrew
2010-03-01
A quantitative microbial risk analysis-Monte Carlo method was used to estimate norovirus infection risks to consumers of wastewater-irrigated lettuce. Using the same assumptions as used in the 2006 WHO guidelines for the safe use of wastewater in agriculture, a norovirus reduction of 6 log units was required to achieve a norovirus infection risk of approximately 10(-3) per person per year (pppy), but for a lower consumption of lettuce (40-48 g per week vs. 350 g per week) the required reduction was 5 log units. If the tolerable additional disease burden is increased from a DALY (disability-adjusted life year) loss of 10(-6) pppy (the value used in the WHO guidelines) to 10(-5) pppy, the required pathogen reduction is one order of magnitude lower. Reductions of 4-6 log units can be achieved by very simple partial treatment (principally settling to achieve a 1-log unit reduction) supplemented by very reliable post-treatment health-protection control measures such as pathogen die-off (1-2 log units), produce washing in cold water (1 log unit) and produce disinfection (3 log units).
-
Review of the logging residue problem and its reduction through marketing practices.
Thomas C. Adams; Richard C. Smith
1976-01-01
This study notes the increasing concern over logging residue in forest land management and describes the various administrative and technological means for accomplishing reductions of logging residue. Alternative sales arrangements can include such things as reduction of stumpage charges for low quality logs or required yarding of unutilized material to the landing or...
-
Kelly-Wintenberg, K; Montie, T C; Brickman, C; Roth, J R; Carr, A K; Sorge, K; Wadsworth, L C; Tsai, P P
1998-01-01
We report the results of an interdisciplinary collaboration formed to assess the sterilizing capabilities of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP). This newly-invented source of glow discharge plasma (the fourth state of matter) is capable of operating at atmospheric pressure in air and other gases, and of providing antimicrobial active species to surfaces and workpieces at room temperature as judged by viable plate counts. OAUGDP exposures have reduced log numbers of bacteria, Staphylococcus aureus and Escherichia coli, and endospores from Bacillus stearothermophilus and Bacillus subtilis on seeded solid surfaces, fabrics, filter paper, and powdered culture media at room temperature. Initial experimental data showed a two-log10 CFU reduction of bacteria when 2 x 10(2) cells were seeded on filter paper. Results showed > or = 3 log10 CFU reduction when polypropylene samples seeded with E. coli (5 x 10(4)) were exposed, while a 30 s exposure time was required for similar killing with S. aureus-seeded polypropylene samples. The exposure times required to effect > or = 6 log10 CFU reduction of E. coli and S. aureus on polypropylene samples were no longer than 30 s. Experiments with seeded samples in sealed commercial sterilization bags showed little or no differences in exposure times compared to unwrapped samples. Plasma exposure times of less than 5 min generated > or = 5 log10 CFU reduction of commercially prepared Bacillus subtilis spores (1 x 10(5)); 7 min OAUGDP exposures were required to generate a > or = 3 log10 CFU reduction for Bacillus stearothermophilus spores. For all microorganisms tested, a biphasic curve was generated when the number of survivors vs time was plotted in dose-response cures. Several proposed mechanisms of killing at room temperature by the OAUGDP are discussed.
-
De Souza, James; Ahmed, Rafath; Strange, Philip; Barbut, Shai; Balamurugan, S
2018-02-02
Dry fermented sausages (DFS) have been subject to numerous validation studies, as pathogen reduction heavily relies on both ingredients and processing. In this study the effect of product caliber size (32, 55, 80mm), and fat level (low, 9.67%; high, 18.46% wt/wt) on the inactivation of E. coli O157:H7 during DFS production was examined. Sausages containing a five-strain cocktail of E. coli O157:H7 at 10 7 CFU/g were manufactured and monitored for changes in physicochemical properties and inoculated E. coli O157:H7 numbers were enumerated during the DFS production stages and log reduction rates were calculated. Significant (P<0.01) reduction in pH from 5.9 to 4.9 was observed in all sausages within 72h of fermentation; however, the observed pH reduction was not significantly (P>0.05) different among sausages of different caliber size or fat levels. No significant (P>0.05) reduction in a w was observed during fermentation of the sausages. However, during the drying phase, sausages with larger caliber sizes required a significantly longer duration of drying to achieve the same a w of smaller caliber size sausages. For instance, to achieve an a w of ≤0.9, following 5days of fermentation/curing, 80mm caliber sausages required up to 27days of drying compared with 13 and 6days for 55 and 32mm caliber size sausages, respectively. Fat levels on the other hand did not significantly (P>0.05) effect the reduction of a w during drying of the sausages. During the fermentation stage there was a significant and rapid reduction in E. coli O157:H7 counts by about 1.1- to 1.4-log units, but was not significantly different among sausages of different caliber size and fat levels. Considering the whole process, only caliber size had a significant effect on log reduction of E. coli O157:H7. ANOVA of log reduction rates of E. coli O157:H7 among sausages of different caliber size and fat levels revealed no significant differences during the fermentation, however, during the drying of the sausages, log reduction rate of E. coli O157:H7 was significantly (P<0.01) lower in sausages with larger caliber sizes and higher fat levels. For instance, log reduction rates for E. coli O157:H7 in high fat large caliber sausages was the lowest at -0.082±0.004 log CFU/g/day compared to all other fat and caliber size combinations. These results suggest that DFS manufacturers producing higher fat and large caliber size products need to consider longer drying periods to achieve the required 5-log inactivation of E. coli O157:H7. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.
-
Pathogen Treatment Guidance and Monitoring Approaches fro ...
On-site non-potable water reuse is increasingly used to augment water supplies, but traditional fecal indicator approaches for defining and monitoring exposure risks are limited when applied to these decentralized options. This session emphasizes risk-based modeling to define pathogen log-reduction requirements coupled with alternative targets for monitoring enabled by genomic sequencing (i.e., the microbiome of reuse systems). 1. Discuss risk-based modeling to define pathogen log-reduction requirements 2. Review alternative targets for monitoring 3. Gain an understanding of how new tools can help improve successful development of sustainable on-site non-potable water reuse Presented at the Water Wastewater Equipment Treatment & Transport Show.
-
Carbon emissions performance of commercial logging in East Kalimantan, Indonesia.
Griscom, Bronson; Ellis, Peter; Putz, Francis E
2014-03-01
Adoption of reduced-impact logging (RIL) methods could reduce CO2 emissions by 30-50% across at least 20% of remaining tropical forests. We developed two cost effective and robust indices for comparing the climate benefits (reduced CO2 emissions) due to RIL. The indices correct for variability in the volume of commercial timber among concessions. We determined that a correction for variability in terrain slope was not needed. We found that concessions certified by the Forest Stewardship Council (FSC, N = 3), when compared with noncertified concessions (N = 6), did not have lower overall CO2 emissions from logging activity (felling, skidding, and hauling). On the other hand, FSC certified concessions did have lower emissions from one type of logging impact (skidding), and we found evidence of a range of improved practices using other field metrics. One explanation of these results may be that FSC criteria and indicators, and associated RIL practices, were not designed to achieve overall emissions reductions. Also, commonly used field metrics are not reliable proxies for overall logging emissions performance. Furthermore, the simple distinction between certified and noncertified concessions does not fully represent the complex history of investments in improved logging practices. To clarify the relationship between RIL and emissions reductions, we propose the more explicit term 'RIL-C' to refer to the subset of RIL practices that can be defined by quantified thresholds and that result in measurable emissions reductions. If tropical forest certification is to be linked with CO2 emissions reductions, certification standards need to explicitly require RIL-C practices. © 2013 John Wiley & Sons Ltd.
-
Pereira, R. V.; Bicalho, M. L.; Machado, V. S.; Lima, S.; Teixeira, A. G.; Warnick, L. D.; Bicalho, R. C.
2015-01-01
Raw milk and colostrum can harbor dangerous micro-organisms that can pose serious health risks for animals and humans. According to the USDA, more than 58% of calves in the United States are fed unpasteurized milk. The aim of this study was to evaluate the effect of UV light on reduction of bacteria in milk and colostrum, and on colostrum IgG. A pilot-scale UV light continuous (UVC) flow-through unit (45 J/cm2) was used to treat milk and colostrum. Colostrum and sterile whole milk were inoculated with Listeria innocua, Mycobacterium smegmatis, Salmonella serovar Typhimurium, Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, and Acinetobacter baumannii before being treated with UVC. During UVC treatment, samples were collected at 5 time points and bacteria were enumerated using selective media. The effect of UVC on IgG was evaluated using raw colostrum from a nearby dairy farm without the addition of bacteria. For each colostrum batch, samples were collected at several different time points and IgG was measured using ELISA. The UVC treatment of milk resulted in a significant final count (log cfu/mL) reduction of Listeria monocytogenes (3.2 ± 0.3 log cfu/mL reduction), Salmonella spp. (3.7 ± 0.2 log cfu/mL reduction), Escherichia coli (2.8 ± 0.2 log cfu/mL reduction), Staph. aureus (3.4 ± 0.3 log cfu/mL reduction), Streptococcus spp. (3.4 ± 0.4 log cfu/mL reduction), and A. baumannii (2.8 ± 0.2 log cfu/mL reduction). The UVC treatment of milk did not result in a significant final count (log cfu/mL) reduction for M. smegmatis (1.8 ± 0.5 log cfu/mL reduction). The UVC treatment of colostrum was significantly associated with a final reduction of bacterial count (log cfu/mL) of Listeria spp. (1.4 ± 0.3 log cfu/mL reduction), Salmonella spp. (1.0 ± 0.2 log cfu/mL reduction), and Acinetobacter spp. (1.1 ± 0.3 log cfu/mL reduction), but not of E. coli (0.5 ± 0.3 log cfu/mL reduction), Strep. agalactiae (0.8 ± 0.2 log cfu/mL reduction), and Staph. aureus (0.4 ± 0.2 log cfu/mL reduction). The UVC treatment of colostrum significantly decreased the IgG concentration, with an observed final mean IgG reduction of approximately 50%. Development of new methods to reduce bacterial contaminants in colostrum must take into consideration the barriers imposed by its opacity and organic components, and account for the incidental damage to IgG caused by manipulating colostrum. PMID:24582452
-
Pereira, R V; Bicalho, M L; Machado, V S; Lima, S; Teixeira, A G; Warnick, L D; Bicalho, R C
2014-05-01
Raw milk and colostrum can harbor dangerous microorganisms that can pose serious health risks for animals and humans. According to the USDA, more than 58% of calves in the United States are fed unpasteurized milk. The aim of this study was to evaluate the effect of UV light on reduction of bacteria in milk and colostrum, and on colostrum IgG. A pilot-scale UV light continuous (UVC) flow-through unit (45 J/cm(2)) was used to treat milk and colostrum. Colostrum and sterile whole milk were inoculated with Listeria innocua, Mycobacterium smegmatis, Salmonella serovar Typhimurium, Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, and Acinetobacter baumannii before being treated with UVC. During UVC treatment, samples were collected at 5 time points and bacteria were enumerated using selective media. The effect of UVC on IgG was evaluated using raw colostrum from a nearby dairy farm without the addition of bacteria. For each colostrum batch, samples were collected at several different time points and IgG was measured using ELISA. The UVC treatment of milk resulted in a significant final count (log cfu/mL) reduction of Listeria monocytogenes (3.2 ± 0.3 log cfu/mL reduction), Salmonella spp. (3.7 ± 0.2 log cfu/mL reduction), Escherichia coli (2.8 ± 0.2 log cfu/mL reduction), Staph. aureus (3.4 ± 0.3 log cfu/mL reduction), Streptococcus spp. (3.4 ± 0.4 log cfu/mL reduction), and A. baumannii (2.8 ± 0.2 log cfu/mL reduction). The UVC treatment of milk did not result in a significant final count (log cfu/mL) reduction for M. smegmatis (1.8 ± 0.5 log cfu/mL reduction). The UVC treatment of colostrum was significantly associated with a final reduction of bacterial count (log cfu/mL) of Listeria spp. (1.4 ± 0.3 log cfu/mL reduction), Salmonella spp. (1.0 ± 0.2 log cfu/mL reduction), and Acinetobacter spp. (1.1 ± 0.3 log cfu/mL reduction), but not of E. coli (0.5 ± 0.3 log cfu/mL reduction), Strep. agalactiae (0.8 ± 0.2 log cfu/mL reduction), and Staph. aureus (0.4 ± 0.2 log cfu/mL reduction). The UVC treatment of colostrum significantly decreased the IgG concentration, with an observed final mean IgG reduction of approximately 50%. Development of new methods to reduce bacterial contaminants in colostrum must take into consideration the barriers imposed by its opacity and organic components, and account for the incidental damage to IgG caused by manipulating colostrum. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
-
Neetoo, Hudaa; Ye, Mu; Chen, Haiqiang
2008-12-10
Sprouts eaten raw are increasingly being perceived as hazardous foods as they have been implicated in Escherichia coli O157:H7 outbreaks where the seeds were found to be the likely source of contamination. The objective of our study was to evaluate the potential of using high hydrostatic pressure (HHP) technology for alfalfa seed decontamination. Alfalfa seeds inoculated with a cocktail of five strains of E. coli O157:H7 were subjected to pressures of 500 and 600 MPa for 2 min at 20 degrees C in a dry or wet (immersed in water) state. Immersing seeds in water during pressurization considerably enhanced inactivation of E. coli O157:H7 achieving reductions of 3.5 log and 5.7 log at 500 and 600 MPa, respectively. When dry seeds were pressurized, both pressure levels reduced the counts by <0.7 log. To test the efficacy of HHP to completely decontaminate seeds whilst meeting the FDA requirement of 5 log reductions, seeds inoculated with a ~5 log CFU/g of E. coli O157:H7 were pressure-treated at 600 and 650 MPa at 20 degrees C for holding times of 2 to 20 min. A >5 log reduction in the population was achieved when 600 MPa was applied for durations of > or =6 min although survivors were still detected by enrichment. When the pressure was stepped up to 650 MPa, the threshold time required to achieve complete elimination was 15 min. Un-inoculated seeds pressure-treated at 650 MPa for 15 min at 20 degrees C successfully sprouted achieving a germination rate identical to untreated seeds after eight days of sprouting. These results therefore demonstrate the promising application of HHP on alfalfa seeds to eliminate the risk of E. coli O157:H7 infections associated with consumption of raw alfalfa sprouts.
-
Crook, Jennifer A; Rossitto, Paul V; Parko, Jared; Koutchma, Tatiana; Cullor, James S
2015-06-01
Nonthermal technologies are being investigated as viable alternatives to, or supplemental utilization, with thermal pasteurization in the food-processing industry. In this study, the effect of ultraviolet (UV)-C light on the inactivation of seven milkborne pathogens (Listeria monocytogenes, Serratia marcescens, Salmonella Senftenberg, Yersinia enterocolitica, Aeromonas hydrophila, Escherichia coli, and Staphylococcus aureus) was evaluated. The pathogens were suspended in ultra-high-temperature whole milk and treated at UV doses between 0 and 5000 J/L at a flow rate of 4300 L/h in a thin-film turbulent flow-through pilot system. Of the seven milkborne pathogens tested, L. monocytogenes was the most UV resistant, requiring 2000 J/L of UV-C exposure to reach a 5-log reduction. The most sensitive bacterium was S. aureus, requiring only 1450 J/L to reach a 5-log reduction. This study demonstrated that the survival curves were nonlinear. Sigmoidal inactivation curves were observed for all tested bacterial strains. Nonlinear modeling of the inactivation data was a better fit than the traditional log-linear approach. Results obtained from this study indicate that UV illumination has the potential to be used as a nonthermal method to reduce microorganism populations in milk.
-
Enns, D K; Crandall, P G; O'Bryan, C A; Griffis, C L; Martin, E M
2007-05-01
Americans consume almost 40 kg per capita of chicken each year. Increasing consumption of chicken surpassed pork in 1982 and beef in 1992. The objectives of this study were to examine the effectiveness of a novel, 2-step cooking method of grilling, slicing, vacuum packaging, and hot water pasteurization to inhibit the growth of Listeria monocytogenes in chicken breast meat. Because this study required the use of pilot plant scale pasteurization equipment, Listeria innocua M1, a nonpathogen with slightly greater heat resistance than L. monocytogenes, was used as a surrogate. We first examined the lethal effects of grilling on a boneless skinless chicken breast to mimic cross-contaminated, surface-inoculated Listeria. Searing produced a mean reduction of 2.5 log CFU/g of Listeria and a moisture loss of only 7% (w/w). A 2nd experiment studied the lethal effect of pasteurization of the sliced seared chicken breast. L. innocua M1 inoculated between the slices mimicked contamination in deep muscle. Pasteurization in a 71 degrees C bath (final internal temperature of 66 degrees C) gave an additional 2.3 log CFU/g reduction. L. innocua M1 did not show significant regrowth during a wk of refrigerated storage. The combined 2-step cooking method of searing and pasteurization gave a combined 4.8 log reduction in LI M1. In parallel tests a non-Listeria indicator, Corynebacterium glutamicum, inoculated between sliced, seared chicken, showed a 3 log reduction after pasteurization for 10 min in a 71 degrees C bath compared to 2.3 log reduction of Listeria. Corynebacterium regrowth occurred much faster than did L. innocua M1.
-
Li, Si-Quan; Zhang, Howard Q; Balasubramaniam, V M; Lee, Young-Zoon; Bomser, Joshua A; Schwartz, Steven J; Dunne, C Patrick
2006-02-08
Immunoglobulin-rich foods may provide health benefits to consumers. To extend the refrigerated shelf life of functional foods enriched with bovine immunoglobulin G (IgG), nonthermal alternatives such as high-pressure processing (HPP) may offer advantages to thermal processing for microbial reduction. To evaluate the effects of HPP on the immunoactivity of bovine IgG, a soymilk product enriched with milk protein concentrates, derived from dairy cows that were hyperimmunized with 26 human pathogens, was subjected to HPP or heat treatment. To achieve a 5 log reduction in inoculated Escherichia coli 8739, the HPP or heat treatment requirements were 345 MPa for 4 min at 30 degrees C or for 20 s at 70 degrees C, respectively. To achieve a 5 log reduction in natural flora in the enriched soymilk, the HPP or heat treatments needed were 552 MPa for 4 min at 30 degrees C or for 120 s at 78.2 degrees C, respectively. At equivalent levels for a 5 log reduction in E. coli, HPP and heat treatment caused 25% and no detectable loss in bovine IgG activity, respectively. However, at equivalent levels for a 5 log reduction in natural flora, HPP and heat resulted in 65 and 85% loss of bovine IgG activity, respectively. Results of combined pressure-thermal kinetic studies of bovine milk IgG activity were provided to determine the optimal process conditions to preserve product function.
-
Ijabadeniyi, Oluwatosin Ademola; Mnyandu, Elizabeth
2017-04-13
The effectiveness of sodium dodecyl sulphate (SDS), sodium hypochlorite solution and levulinic acid in reducing the survival of heat adapted and chlorine adapted Listeria monocytogenes ATCC 7644 was evaluated. The results against heat adapted L. monocytognes revealed that sodium hypochlorite solution was the least effective, achieving log reduction of 2.75, 2.94 and 3.97 log colony forming unit (CFU)/mL for 1, 3 and 5 minutes, respectively. SDS was able to achieve 8 log reduction for both heat adapted and chlorine adapted bacteria. When used against chlorine adapted L. monocytogenes sodium hypochlorite solution achieved log reduction of 2.76, 2.93 and 3.65 log CFU/mL for 1, 3 and 5 minutes, respectively. Using levulinic acid on heat adapted bacteria achieved log reduction of 3.07, 2.78 and 4.97 log CFU/mL for 1, 3, 5 minutes, respectively. On chlorine adapted bacteria levulinic acid achieved log reduction of 2.77, 3.07 and 5.21 log CFU/mL for 1, 3 and 5 minutes, respectively. Using a mixture of 0.05% SDS and 0.5% levulinic acid on heat adapted bacteria achieved log reduction of 3.13, 3.32 and 4.79 log CFU/mL for 1, 3 and 5 minutes while on chlorine adapted bacteria it achieved 3.20, 3.33 and 5.66 log CFU/mL, respectively. Increasing contact time also increased log reduction for both test pathogens. A storage period of up to 72 hours resulted in progressive log reduction for both test pathogens. Results also revealed that there was a significant difference (P≤0.05) among contact times, storage times and sanitizers. Findings from this study can be used to select suitable sanitizers and contact times for heat and chlorine adapted L. monocytogenes in the fresh produce industry.
-
40 CFR 1042.110 - Recording reductant use and other diagnostic functions.
Code of Federal Regulations, 2010 CFR
2010-07-01
...) The onboard computer log must record in nonvolatile computer memory all incidents of engine operation... such operation in nonvolatile computer memory. You are not required to monitor NOX concentrations...
-
Evaluation of waste mushroom logs as a potential biomass resource for the production of bioethanol.
Lee, Jae-Won; Koo, Bon-Wook; Choi, Joon-Weon; Choi, Don-Ha; Choi, In-Gyu
2008-05-01
In order to investigate the possibility of using waste mushroom logs as a biomass resource for alternative energy production, the chemical and physical characteristics of normal wood and waste mushroom logs were examined. Size reduction of normal wood (145 kW h/tone) required significantly higher energy consumption than waste mushroom logs (70 kW h/tone). The crystallinity value of waste mushroom logs was dramatically lower (33%) than normal wood (49%) after cultivation by Lentinus edodes as spawn. Lignin, an enzymatic hydrolysis inhibitor in sugar production, decreased from 21.07% to 18.78% after inoculation of L. edodes. Total sugar yields obtained by enzyme and acid hydrolysis were higher in waste mushroom logs than in normal wood. After 24h fermentation, 12 g/L ethanol was produced on waste mushroom logs, while normal wood produced 8 g/L ethanol. These results indicate that waste mushroom logs are economically suitable lignocellulosic material for the production of fermentable sugars related to bioethanol production.
-
Park, Sang-Hyun; Choi, Mi-Ran; Park, Jeong-Woong; Park, Ki-Hwan; Chung, Myung-Sub; Ryu, Sangryeol; Kang, Dong-Hyun
2011-08-01
This study was undertaken to investigate the antimicrobial effect of organic acids against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on whole red organic apples and lettuce. Several studies have been conducted to evaluate organic acids as sanitizers. However, no studies have compared antimicrobial effects of various organic acids on organic fresh produce, including evaluation of color changes of produce. Apples and lettuce were inoculated with a cocktail of 3 strains each of 3 foodborne pathogens provided above and treated with 1% and 2% organic acids (propionic, acetic, lactic, malic, and citric acid) for 0, 0.5, 1, 5, and 10 min. With increasing treatment time and acid concentration, organic acid treatments showed significant reduction compared to the control treatment (distilled water), and differences in antimicrobial effects between organic acids were observed. After 10 min of treatment with 1% and 2% organic acids in apples, propionic (0.92 to 2.75 log reduction), acetic (0.52 to 2.78 log reduction), lactic (1.69 to >3.42 log reduction), malic (1.48 to >3.42 log reduction), and citric acid (1.52 to >3.42 log reduction) exhibited significant (P < 0.05) antibacterial effects against 3 foodborne pathogens compared to the control treatment. In lettuce, propionic (0.93 to 1.52 log reduction), acetic (1.13 to 1.74 log reduction), lactic (1.87 to 2.54 log reduction), malic (2.32 to 2.98 log reduction), and citric acid (1.85 to 2.86 log reduction) showed significant (P < 0.05) effects compared to the control treatment. Changes in sample color subjected to organic acids treatment were not significant during storage. It is suggested that organic acids have a potential as sanitizers for organic fresh produce. These data may help the organic produce industry provide safe fresh produce for consumers. © 2011 Institute of Food Technologists®
-
de Sousa Guedes, Jossana Pereira; da Costa Medeiros, José Alberto; de Souza E Silva, Richard Sidney; de Sousa, Janaína Maria Batista; da Conceição, Maria Lúcia; de Souza, Evandro Leite
2016-12-05
This study evaluated the ability of the essential oil from Mentha arvensis L. (MAEO) and M. piperita L. (MPEO) to induce ≥5-log reductions in counts (CFU/mL) of E. coli, L. monocytogenes, and Salmonella enterica serovar Enteritidis in Brain-Heart Infusion broth (BHIB) and cashew, guava, mango, and pineapple juices during refrigerated storage (4±0.5°C). The effects of the incorporation of these essential oils on some physicochemical and sensory parameters of juices were also evaluated. The incorporation of 5, 2.5, 1.25, or 0.625μL/mL of MAEO in BHIB caused a ≥5-log reduction in counts of E. coli and Salmonella Enteritidis after 24h of storage; but only 5μL/mL was able to cause the same reduction in counts of L.monocytogenes. The incorporation of 10μL/mL of MPEO in BHIB caused a ≥5-log reduction in counts of E. coli, Salmonella Enteritidis, and L. monocytogenes after 24h of storage; smaller reductions were observed in BHIB containing 5, 2.5, and 1.25μL/mL of MPEO. Similar reductions were observed when the MAEO or MPEO was incorporated at the same concentrations in mango juice. The incorporation of MAEO or MPEO at all tested concentrations in cashew, guava, and pineapple juices resulted in a ≥5-log reduction in pathogen counts within 1h. The incorporation of MAEO and MPEO (0.625 and 1.25μL/mL, respectively) in fruit juices did not induce alterations in °Brix, pH, and acidity, but negatively affected the taste, aftertaste, and overall acceptance. The use of MAEO or MPEO at low concentrations could constitute an interesting tool to achieve the required 5-log reduction of pathogenic bacteria in cashew, guava, mango, and pineapple fruit juices. However, new methods combining the use of MAEO or MPEO with other technologies are necessary to reduce their negative impacts on specific sensory properties of these juices. Copyright © 2016 Elsevier B.V. All rights reserved.
-
Ferrario, Mariana I; Guerrero, Sandra N
The purpose of this study was to analyze the response of different initial contamination levels of Alicyclobacillus acidoterrestris ATCC 49025 spores in apple juice as affected by pulsed light treatment (PL, batch mode, xenon lamp, 3pulses/s, 0-71.6J/cm 2 ). Biphasic and Weibull frequency distribution models were used to characterize the relationship between inoculum size and treatment time with the reductions achieved after PL exposure. Additionally, a second order polynomial model was computed to relate required PL processing time to inoculum size and requested log reductions. PL treatment caused up to 3.0-3.5 log reductions, depending on the initial inoculum size. Inactivation curves corresponding to PL-treated samples were adequately characterized by both Weibull and biphasic models (R adj 2 94-96%), and revealed that lower initial inoculum sizes were associated with higher inactivation rates. According to the polynomial model, the predicted time for PL treatment increased exponentially with inoculum size. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.
-
Escudero, M E; Velázquez, L; Favier, G; de Guzmán, A M
2003-06-01
This study assessed the effectiveness of 200 and 500 ppm of chlorine and organic acids (0.5% lactic acid and 0.5% citric acid) in wash solutions, and UV radiation for reducing Escherichia coli O157:H7 and Yersinia enterocolitica on apples contaminated by two different methods. Residual levels of these pathogens after different treatments were compared. On dip inoculated apples, Y. enterocolitica reductions of 2.66 and 2.77 logs were obtained with 200 and 500 ppm chlorine combined with 0.5% lactic acid, respectively. The E. coli O157:H7 population decreased 3.35 log with 0.5% lactic acid wash solution, and 2.72 and 2.62 logs after 500 ppm chlorine and 500 ppm chlorine plus 0.5% lactic acid treatments, respectively. Similar reductions were obtained with UV radiation. On spot inoculated apples, significant (p < 0.05) decreases of 4.67 and 4.58 logs were observed in E. coli O157:H7 and Y. enterocolitica levels, respectively, after 500 ppm chlorine plus 0.5% lactic acid treatment as compared with the control. In sectioned apples, microorganisms infiltrated in inner core region and pulp were not significantly (p < 0.05) affected by disinfection treatments. No pathogens were detected in the natural microflora on apples. Reductions such as those obtained with 500 ppm chlorine plus 0.5% lactic acid solution were very proximal to the 5-log score required by FDA for apple disinfection.
-
Reduction of lithologic-log data to numbers for use in the digital computer
Morgan, C.O.; McNellis, J.M.
1971-01-01
The development of a standardized system for conveniently coding lithologic-log data for use in the digital computer has long been needed. The technique suggested involves a reduction of the original written alphanumeric log to a numeric log by use of computer programs. This numeric log can then be retrieved as a written log, interrogated for pertinent information, or analyzed statistically. ?? 1971 Plenum Publishing Corporation.
-
Cromeans, Theresa L.; Kahler, Amy M.; Hill, Vincent R.
2010-01-01
Inactivation of infectious viruses during drinking water treatment is usually achieved with free chlorine. Many drinking water utilities in the United States now use monochloramine as a secondary disinfectant to minimize disinfectant by-product formation and biofilm growth. The inactivation of human adenoviruses 2, 40, and 41 (HAdV2, HAdV40, and HAdV41), coxsackieviruses B3 and B5 (CVB3 and CVB5), echoviruses 1 and 11 (E1 and E11), and murine norovirus (MNV) are compared in this study. Experiments were performed with 0.2 mg of free chlorine or 1 mg of monochloramine/liter at pH 7 and 8 in buffered reagent-grade water at 5°C. CT values (disinfectant concentration × time) for 2- to 4-log10 (99 to 99.99%) reductions in virus titers were calculated by using the efficiency factor Hom model. The enteroviruses required the longest times for chlorine inactivation and MNV the least time. CVB5 required the longest exposure time, with CT values of 7.4 and 10 mg·min/liter (pH 7 and 8) for 4-log10 inactivation. Monochloramine disinfection was most effective for E1 (CT values ranged from 8 to 18 mg·min/liter for 2- and 3-log10 reductions, respectively). E11 and HAdV2 were the least susceptible to monochloramine disinfection (CT values of 1,300 and 1,600 mg-min/liter for 3-log10 reductions, respectively). Monochloramine inactivation was most successful for the adenoviruses, CVB5, and E1 at pH 7. A greater variation in inactivation rates between viruses was observed during monochloramine disinfection than during chlorine disinfection. These data will be useful in drinking water risk assessment studies and disinfection system planning. PMID:20023080
-
Disinfection efficacy of contact lens care solutions against ocular pathogens.
Miller, M J; Callahan, D E; McGrath, D; Manchester, R; Norton, S E
2001-01-01
Three commercially available products labeled as multi-purpose contact lens solutions, one multi-purpose disinfecting solution, and a hydrogen peroxide system were evaluated for antimicrobial activity according to the current International Organization for Standardization (ISO) and the U.S. Food and Drug Administration (FDA) stand-alone procedure for disinfecting products. One multi-purpose solution was selected to assess its antimicrobial activity against two human corneal isolates of Pseudomonas aeruginosa. Products were challenged with bacteria and fungi, and following a specified period, aliquots of inoculated test solution were neutralized and plated on validated recovery media. After incubation the number of viable microorganisms was enumerated and mean log reductions determined. ReNu MultiPlus (Bausch & Lomb, Rochester, NY), AOSEPT (CIBA Vision Corporation, Duluth, GA), and Opti-Free Express with Aldox (Alcon Laboratories, Ft. Worth, TX) were the only lens care products that met the stand-alone criteria for all required microorganisms within their minimum recommended disinfection time. Of these, ReNu MultiPlus provided the greatest overall antimicrobial activity. ReNu MultiPlus demonstrated a significantly higher mean log reduction of Staphylococcus aureus and Serratia marcescens than Opti-Free Express. ReNu MultiPlus also gave a higher mean log reduction of S. aureus and S. marcescens than AOSEPT, and a higher mean log reduction of Candida albicans and Fusarium solani than AOSEPT, Complete Comfort Plus (Allergan, Irivine, CA), and Solo-Care (CIBA Vision Corp.) (at 4 hours). Both Complete Comfort Plus and Solo-Care (at 4 hours) met the primary acceptance criteria for bacteria; however, neither product possessed enough antimicrobial activity to meet the minimum criteria for yeast or mold. ReNu Multiplus was effective against corneal isolates of P. aeruginosa. ReNu MultiPlus, AOSEPT, and Opti-Free Express met the requirements of the stand-alone primary criteria for disinfecting solutions. ReNu MultiPlus demonstrated the greatest overall disinfection efficacy, as well as excellent activity against clinical strains of P. aeruginosa.
-
Park, Shin Young; Ha, Sang-Do
2017-10-01
Optimally ripened commercial cabbage kimchi is considered the main cause of enteric norovirus (NoV) outbreaks in Korea. This study investigated the effect of 1-10kGy gamma radiation on the inactivation of murine norovirus-1 (MNV-1; initial inoculum of 5-6log 10 PFU/ml), used as a human NoV surrogate, in kimchi. The effects of gamma radiation on the pH and acidity were also examined to address the index of quality and fermentation, respectively. Titers of MNV-1 significantly reduced (p<0.05) in kimchi subjected to increasing gamma radiation doses: MNV-1 titers in kimchi after 1, 3, 5, 7, and 10kGy were 4.82 (0.34-log 10 reduction), 4.45 (0.71-log 10 reduction), 4.18 (0.98-log 10 reduction), 3.71 (1.45-log 10 reduction), and 3.40 (1.76-log 10 reduction) log 10 PFU/ml, respectively. However, the values of pH (4.5-4.6) and acidity (0.6-0.7%) were not significantly different between non-irradiated and irradiated kimchi (p>0.05). The D-value (1-log reduction) for MNV-1 in kimchi, calculated using first-order kinetics, was 5.75kGy (R 2 =0.98, RMSE=0.10). Therefore, this study suggests that the use of ≥5.75kGy gamma radiation in the kimchi manufacturing industry could be very effective in reducing NoV contamination by >90% (1 log), without causing changes in quality and fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
Guan, Jiewen; Chan, Maria; Brooks, Brian W.; Rohonczy, Liz
2013-01-01
This study evaluated the influence of temperature and organic load on the effectiveness of domestic bleach (DB), Surface Decontamination Foam (SDF), and Virkon in inactivating Geobacillus stearothermophilus spores, which are a surrogate for Bacillus anthracis spores. The spores were suspended in light or heavy organic preparations and the suspension was applied to stainless steel carrier disks. The dried spore inoculum was covered with the disinfectants and the disks were then incubated at various temperatures. At −20°C, the 3 disinfectants caused less than a 2.0 log10 reduction of spores in both organic preparations during a 24-h test period. At 4°C, the DB caused a 4.4 log10 reduction of spores in light organic preparations within 2 h, which was about 3 log10 higher than what was achieved with SDF or Virkon. In heavy organic preparations, after 24 h at 4°C the SDF had reduced the spore count by 4.5 log10, which was about 2 log10 higher than for DB or Virkon. In general, the disinfectants were most effective at 23°C but a 24-h contact time was required for SDF and Virkon to reduce spore counts in both organic preparations by at least 5.5 log10. Comparable disinfecting activity with DB only occurred with the light organic load. In summary, at temperatures as low as 4°C, DB was the most effective disinfectant, inactivating spores within 2 h on surfaces with a light organic load, whereas SDF produced the greatest reduction of spores within 24 h on surfaces with a heavy organic load. PMID:24082400
-
Hygienic effects and gas production of plastic bio-digesters under tropical conditions.
Yen-Phi, Vo Thi; Clemens, Joachim; Rechenburg, Andrea; Vinneras, Björn; Lenssen, Christina; Kistemann, Thomas
2009-12-01
Plastic plug-flow bio-digesters have been promoted as a good option for improved treatment of manure and wastewater in developing countries although minimal information has been published on their hygienic status. This bench-scale study replicates bio-digester conditions to evaluate the reduction of pathogen and indicator microorganisms at three different hydraulic retention times (HRT) in the anaerobic treatment of pig manures at 30 degrees C for 50 days. Results showed that physicochemical values differed between HRTs. Gas production efficiency was better for longer HRTS. The accumulated sludge at the reactor's base increased with longer HRT. Phages and bacteria examined were reduced, but none was completely eliminated. Log10 reduction of bacteria ranged from 0.54 to 2.47. Phages ranged from 1.60 to 3.42. The reduction of organisms at HRT = 30 days was about one log10 unit higher than HRT = 15 days and about two log10 units higher than HRT = 3 days. The results indicate that the reduction of tested organisms increases with HRT. However the hygienic quality of the liquid effluent does not meet required quality values for surface and irrigation water. Longer HRTs are recommended to increase gas yield and achieve higher pathogen reduction. More barriers should be applied while handling bio-digester outputs to minimise risks to environmental and human health.
-
Code of Federal Regulations, 2012 CFR
2012-01-01
... reduction of other pathogens and their toxins or toxic metabolites necessary to prevent adulteration, must... botulinum, and no more than a 1 log10 multiplication of Clostridium perfringens within the product. (b...
-
Code of Federal Regulations, 2013 CFR
2013-01-01
... reduction of other pathogens and their toxins or toxic metabolites necessary to prevent adulteration, must... botulinum, and no more than a 1 log10 multiplication of Clostridium perfringens within the product. (b...
-
Code of Federal Regulations, 2014 CFR
2014-01-01
... reduction of other pathogens and their toxins or toxic metabolites necessary to prevent adulteration, must... botulinum, and no more than a 1 log10 multiplication of Clostridium perfringens within the product. (b...
-
Controlled iodine release from polyurethane sponges for water decontamination.
Aviv, Oren; Laout, Natalia; Ratner, Stanislav; Harik, Oshrat; Kunduru, Konda Reddy; Domb, Abraham J
2013-12-28
Iodinated polyurethane (IPU) sponges were prepared by immersing sponges in aqueous/organic solutions of iodine or exposing sponges to iodine vapors. Iodine was readily adsorbed into the polymers up to 100% (w/w). The adsorption of iodine on the surface was characterized by XPS and SEM analyses. The iodine loaded IPU sponges were coated with ethylene vinyl acetate (EVA), in order to release iodine in a controlled rate for water decontamination combined with active carbon cartridge, which adsorbs the iodine residues after the microbial inactivation. The EVA coated IPU were incorporated in a water purifier and tested for iodine release to water and for microbial inactivation efficiency according to WQA certification program against P231/EPA for 250l, using 25l a day with flow rate of 6-8min/1l. The antimicrobial activity was also studied against Escherichia coli and MS2 phage. Bacterial results exceeded the minimal requirement for bacterial removal of 6log reduction throughout the entire lifespan. At any testing point, no bacteria was detected in the outlet achieving more than 7.1 to more than 8log reduction as calculated upon the inlet concentration. Virus surrogate, MS2, reduction results varied from 4.11log reduction under tap water, and 5.11log reduction under basic water (pH9) to 1.32 for acidic water (pH5). Controlled and stable iodine release was observed with the EVA coated IPU sponges and was effective in deactivating the bacteria and virus present in the contaminated water and thus, these iodinated PU systems could be used in water purification to provide safe drinking water. These sponges may find applications as disinfectants in medicine. © 2013.
-
Balamurugan, S; Ahmed, Rafath; Gao, Anli; Strange, Phil
2017-10-16
The study examined the relative fate of the top six non-O157 shiga-toxin producing Escherichia coli (STEC) and E. coli O157:H7 during the manufacture of dry fermented sausages (DFS). Three separate batches of sausages containing a five-strain cocktail for each serogroup and uninoculated control were manufactured and subjected to identical fermentation, maturation and dry curing conditions. Changes in physicochemical properties and inoculated STEC numbers were enumerated during the DFS production stages and log reduction and log reduction rates were calculated. Inoculation of very high concentrations (8logCFUg -1 ) of STEC in the sausage batter did not significantly (P>0.05) affect the changes in the pH, a w , moisture, protein, fat content compared to the uninoculated DFS. There was a significant (P<0.05) reduction in counts within the 48h fermentation for all STEC serogroups inoculated by about 0.97- to 1.42-log units. However, during the sausage maturation stage, all serogroups except O121 and O45 showed a significant reduction in numbers. During the extended 34day drying stage, all STEC serogroups showed a significant reduction in counts reaching a 5-log reduction within 20 to 27days of drying. ANOVA of the log reduction rates revealed significant differences in the reduction rates among the STEC serogroups examined. During the fermentation stage, serogroup O45 had the highest reduction rate at 0.98-logCFUg -1 day -1 which was significantly higher compared to all other STEC serogroups (P<0.05), while O26 was the most tolerant to the conditions encountered during the fermentation stage with a reduction rate of 0.49-logCFUg -1 day -1 . However, during the extended 34days drying stage all STEC serogroups showed a steady reduction in population with a reduction rate ranging from 0.11- to 0.18-logCFUg -1 day -1 . The log reduction rate of E. coli O157:H7 was similar to that of serogroups O111 and O103, but was significantly lower (P<0.05) than all other STEC serogroups examined in the study. The log reduction rates of serogroups O121, O45, O145 and O26 during drying were not significantly different (P>0.05) from each other. These results indicate that the lethality of DFS production processes observed against E. coli O157:H7 would result in a similar inactivation of the top six non-O157 STEC. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.
-
Code of Federal Regulations, 2011 CFR
2011-01-01
... standards: (1) Lethality. A 7-log10 reduction of Salmonella or an alternative lethality that achieves an equivalent probability that no viable Salmonella organisms remain in the finished product, as well as the...
-
Spinelli, Raffaele; Aalmo, Giovanna Ottaviani; Magagnotti, Natascia
2015-01-01
The authors conducted a comparative test to determine whether the introduction of a hydraulic slack puller allowed reducing the physiological workload of operators assigned to log winching tasks. The tests were conducted in northern Italy, on the mountains near Como. The study involved five volunteer subjects, considered representatives of the regional logging workforce. Physiological workload was determined by measuring the operators' heart rate upon completion of specific tasks. The slack puller improved the efficiency of downhill winching, since it allowed a single operator to pull out the cable on his own, without requiring the assistance of a colleague. However, introduction of the slack puller did not result in any reductions of operator physiological workload. The main stressor when working on a steep slope is moving up and down the slope: pulling a cable is only a secondary stressor. Any measures targeting secondary stressors are unlikely to produce dramatic reductions of operator workload.
-
Reduction of Salmonella in ground chicken using a bacteriophage.
Grant, Ar'Quette; Parveen, Salina; Schwarz, Jurgen; Hashem, Fawzy; Vimini, Bob
2017-08-01
This study's goal was to ascertain the effectiveness of a commercially available Salmonella bacteriophage during ground chicken production focusing on: water source, different Salmonella serovars, and time. Salmonella-free boneless, skinless chicken meat was inoculated with 4.0 Log CFU/cm2 of either a cocktail of 3 Salmonella isolates derived from ground chicken (GC) or a cocktail of 3 Salmonella strains not isolated from ground chicken (non-GC). Bacteriophages were spread onto the chicken using sterile tap or filtered water for 30 min or 8 h. Salmonella was recovered using standard plating method. Greater Salmonella reduction was observed when the bacteriophage was diluted in sterile tap water than in sterile filtered water: 0.39 Log CFU/cm2 and 0.23 Log CFU/cm2 reduction after 30 min, respectively (P < 0.05). The non-GC isolates showed reductions of 0.71 Log CFU/cm2 and 0.90 Log CFU/cm2 after 30 min and 8 h, respectively (P < 0.05). The GC isolates were less sensitive to the bacteriophage: 0.39 Log CFU/cm2 and 0.67 Log CFU/cm2 reductions after 30 min and 8 h, respectively (P < 0.05). In conclusion, bacteriophage reduction was dependent on water used to dilute the bacteriophage, Salmonella's susceptibility to the bacteriophage, and treatment time. © 2017 Poultry Science Association Inc.
-
Pouillot, Régis; Van Doren, Jane M; Woods, Jacquelina; Plante, Daniel; Smith, Mark; Goblick, Gregory; Roberts, Christopher; Locas, Annie; Hajen, Walter; Stobo, Jeffrey; White, John; Holtzman, Jennifer; Buenaventura, Enrico; Burkhardt, William; Catford, Angela; Edwards, Robyn; DePaola, Angelo; Calci, Kevin R
2015-07-01
Human norovirus (NoV) is the leading cause of foodborne illness in the United States and Canada. Wastewater treatment plant (WWTP) effluents impacting bivalve mollusk-growing areas are potential sources of NoV contamination. We have developed a meta-analysis that evaluates WWTP influent concentrations and log10 reductions of NoV genotype I (NoV GI; in numbers of genome copies per liter [gc/liter]), NoV genotype II (NoV GII; in gc/liter), and male-specific coliphage (MSC; in number of PFU per liter), a proposed viral surrogate for NoV. The meta-analysis included relevant data (2,943 measurements) reported in the scientific literature through September 2013 and previously unpublished surveillance data from the United States and Canada. Model results indicated that the mean WWTP influent concentration of NoV GII (3.9 log10 gc/liter; 95% credible interval [CI], 3.5, 4.3 log10 gc/liter) is larger than the value for NoV GI (1.5 log10 gc/liter; 95% CI, 0.4, 2.4 log10 gc/liter), with large variations occurring from one WWTP to another. For WWTPs with mechanical systems and chlorine disinfection, mean log10 reductions were -2.4 log10 gc/liter (95% CI, -3.9, -1.1 log10 gc/liter) for NoV GI, -2.7 log10 gc/liter (95% CI, -3.6, -1.9 log10 gc/liter) for NoV GII, and -2.9 log10 PFU per liter (95% CI, -3.4, -2.4 log10 PFU per liter) for MSCs. Comparable values for WWTPs with lagoon systems and chlorine disinfection were -1.4 log10 gc/liter (95% CI, -3.3, 0.5 log10 gc/liter) for NoV GI, -1.7 log10 gc/liter (95% CI, -3.1, -0.3 log10 gc/liter) for NoV GII, and -3.6 log10 PFU per liter (95% CI, -4.8, -2.4 PFU per liter) for MSCs. Within WWTPs, correlations exist between mean NoV GI and NoV GII influent concentrations and between the mean log10 reduction in NoV GII and the mean log10 reduction in MSCs. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
-
As decentralized water reuse continues to gain popularity, risk-based treatment guidance is increasingly sought for the protection of public health. However, efforts to evaluate pathogen risks and log-reduction requirements have been hindered by an incomplete understanding of pat...
-
Strength of log bridge stringers after several year’s use in southeast Alaska
Russell C. Moody; R.L. Tuomi; W.E. Eslyn; F.W. Muchmore
1979-01-01
Bending tests of 28 untreated log stringers from 12-year-old native timber bridges in southeast Alaska showed significant reductions in strength due to decay. Compared to results on fresh logs, strength reduction was about 25 percent, and could be predicted based on the loss in section modulus due to decay. Log stiffness was not significantly affected. Results will be...
-
Prado-Silva, Leonardo; Cadavez, Vasco; Gonzales-Barron, Ursula; Rezende, Ana Carolina B.
2015-01-01
The aim of this study was to perform a meta-analysis of the effects of sanitizing treatments of fresh produce on Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. From 55 primary studies found to report on such effects, 40 were selected based on specific criteria, leading to more than 1,000 data on mean log reductions of these three bacterial pathogens impairing the safety of fresh produce. Data were partitioned to build three meta-analytical models that could allow the assessment of differences in mean log reductions among pathogens, fresh produce, and sanitizers. Moderating variables assessed in the meta-analytical models included type of fresh produce, type of sanitizer, concentration, and treatment time and temperature. Further, a proposal was done to classify the sanitizers according to bactericidal efficacy by means of a meta-analytical dendrogram. The results indicated that both time and temperature significantly affected the mean log reductions of the sanitizing treatment (P < 0.0001). In general, sanitizer treatments led to lower mean log reductions when applied to leafy greens (for example, 0.68 log reductions [0.00 to 1.37] achieved in lettuce) compared to other, nonleafy vegetables (for example, 3.04 mean log reductions [2.32 to 3.76] obtained for carrots). Among the pathogens, E. coli O157:H7 was more resistant to ozone (1.6 mean log reductions), while L. monocytogenes and Salmonella presented high resistance to organic acids, such as citric acid, acetic acid, and lactic acid (∼3.0 mean log reductions). With regard to the sanitizers, it has been found that slightly acidic electrolyzed water, acidified sodium chlorite, and the gaseous chlorine dioxide clustered together, indicating that they possessed the strongest bactericidal effect. The results reported seem to be an important achievement for advancing the global understanding of the effectiveness of sanitizers for microbial safety of fresh produce. PMID:26362982
-
The effect of riboflavin and ultraviolet light on the infectivity of arboviruses.
Faddy, Helen M; Prow, Natalie A; Fryk, Jesse J; Hall, Roy A; Keil, Shawn D; Goodrich, Raymond P; Marks, Denese C
2015-04-01
Arboviruses are an emerging threat to transfusion safety and rates of infection are likely to increase with the increased rainfall associated with climate change. Arboviral infections are common in Australia, where Ross River virus (RRV), Barmah Forest virus (BFV), and Murray Valley encephalitis virus (MVEV), among others, have the potential to cause disease in humans. The use of pathogen reduction technology (PRT) may be an alternative approach for blood services to manage the risk of arboviral transfusion transmission. In this study, the effectiveness of the Mirasol PRT (Terumo BCT) system at inactivating RRV, BFV, and MVEV in buffy coat (BC)-derived platelets (PLTs) was investigated. BC-derived PLT concentrates in additive solution (SSP+) were spiked with RRV, BFV, or MVEV and then treated with the Mirasol PRT system. The level of infectious virus was determined before and after treatment, and the reduction in viral infectivity was calculated. Treatment with PRT (Mirasol) reduced the amount of infectious virus of all three arboviruses. The greatest level of inactivation was observed for RRV (2.33 log; 99.25%), followed by BFV (1.97 log; 98.68%) and then MVEV (1.83 log; 98.42%). Our study demonstrates that treatment of PLT concentrates with PRT (Mirasol) reduces the infectious levels of RRV, BFV, and MVEV. The relevance of the level of reduction required to prevent disease transmission by transfusion has not been fully defined and requires further investigation. In the face of a changing climate, with its associated threat to blood safety, PRT represents a proactive approach for maintaining blood safety. © 2014 AABB.
-
Cost analysis of commercial pasteurization of orange juice by pulsed electric fields
USDA-ARS?s Scientific Manuscript database
The cost of pulsed electric field (PEF) pasteurization of orange juice was estimated. The cost analysis was based on processing conditions that met the US FDA (5 log reduction) requirement for fruit juice pasteurization and that achieved a 2 month microbial shelf-life. PEF-treated samples processed ...
-
Titanium dioxide/UV photocatalytic disinfection in fresh carrots.
Cho, Mihee; Choi, Yoonjung; Park, Hyojin; Kim, Kwansik; Woo, Gun-Jo; Park, Jiyong
2007-01-01
Increased occurrences of fresh produce-related outbreaks of foodborne illness have focused attention on effective washing processes for fruits and vegetables. A titanium dioxide (TiO2) photocatalytic reaction under UV radiation provides a high rate of disinfection. The photo-killing effects of TiO2 on bacteria in liquid cultures under experimental conditions have been widely studied. However, the disinfection effects of the TiO2 photocatalytic reaction on fresh vegetables during a washing process have not been evaluated. Our objectives were to design a pilot-scale TiO2/UV photocatalytic reactor for fresh carrots and to compare the bactericidal effects of the TiO2/UV reaction against bacteria in liquid media and on carrots. TiO2/UV photocatalytic reactions for 40, 60, and 30 s were required for the complete killing of Escherichia coli, Salmonella Typhimurium, and Bacillus cereus (initial counts of approximately 6.7 log CFU/ml), respectively. The counts of total aerobic bacteria in fresh carrots and foodborne pathogenic bacteria in inoculated carrots were also measured. Counts of total aerobic bacteria were reduced by 1.8 log CFU/g after TiO2/UV photocatalytic disinfection for 20 min compared with a 1.1-log CFU/g reduction by UV alone. E. coli, Salmonella Typhimurium, and B. cereus (8 log CFU/ml) were inoculated onto carrots, and the number of surviving bacteria in carrots was determined after treatment. The TiO2/UV treatment exhibited 2.1-, 2.3-, and 1.8-log CFU/g reductions in the counts of E. coli, Salmonella Typhimurium, and B. cereus, respectively, compared with 1.3-, 1.2-, and 1.2-log CFU/g reductions by UV alone. The TiO2/UV photocatalyst reaction showed significant bactericidal effects, indicating that this process is applicable to nonthermal disinfection of fresh vegetables.
-
Bryan, Jane; Shearman, Phil; Ash, Julian; Kirkpatrick, J B
2010-01-01
Reduction of carbon emissions from tropical deforestation and forest degradation is being considered a cost-effective way of mitigating the impacts of global warming. If such reductions are to be implemented, accurate and repeatable measurements of forest cover change and biomass will be required. In Papua New Guinea (PNG), which has one of the world's largest remaining areas of tropical forest, we used the best available data to estimate rainforest carbon stocks, and emissions from deforestation and degradation. We collated all available PNG field measurements which could be used to estimate carbon stocks in logged and unlogged forest. We extrapolated these plot-level estimates across the forested landscape using high-resolution forest mapping. We found the best estimate of forest carbon stocks contained in logged and unlogged forest in 2002 to be 4770 Mt (+/-13%). Our best estimate of gross forest carbon released through deforestation and degradation between 1972 and 2002 was 1178 Mt (+/-18%). By applying a long-term forest change model, we estimated that the carbon loss resulting from deforestation and degradation in 2001 was 53 Mt (+/-18%), rising from 24 Mt (+/-15%) in 1972. Forty-one percent of 2001 emissions resulted from logging, rising from 21% in 1972. Reducing emissions from logging is therefore a priority for PNG. The large uncertainty in our estimates of carbon stocks and fluxes is primarily due to the dearth of field measurements in both logged and unlogged forest, and the lack of PNG logging damage studies. Research priorities for PNG to increase the accuracy of forest carbon stock assessments are the collection of field measurements in unlogged forest and more spatially explicit logging damage studies. Copyright 2009 Elsevier Ltd. All rights reserved.
-
Devos, Stefanie; Cox, Bianca; van Lier, Tom; Nawrot, Tim S; Putman, Koen
2016-09-01
We used log-linear and log-log exposure-response (E-R) functions to model the association between PM2.5 exposure and non-elective hospitalizations for pneumonia, and estimated the attributable hospital costs by using the effect estimates obtained from both functions. We used hospital discharge data on 3519 non-elective pneumonia admissions from UZ Brussels between 2007 and 2012 and we combined a case-crossover design with distributed lag models. The annual averted pneumonia hospitalization costs for a reduction in PM2.5 exposure from the mean (21.4μg/m(3)) to the WHO guideline for annual mean PM2.5 (10μg/m(3)) were estimated and extrapolated for Belgium. Non-elective hospitalizations for pneumonia were significantly associated with PM2.5 exposure in both models. Using a log-linear E-R function, the estimated risk reduction for pneumonia hospitalization associated with a decrease in mean PM2.5 exposure to 10μg/m(3) was 4.9%. The corresponding estimate for the log-log model was 10.7%. These estimates translate to an annual pneumonia hospital cost saving in Belgium of €15.5 million and almost €34 million for the log-linear and log-log E-R function, respectively. Although further research is required to assess the shape of the association between PM2.5 exposure and pneumonia hospitalizations, we demonstrated that estimates for health effects and associated costs heavily depend on the assumed E-R function. These results are important for policy making, as supra-linear E-R associations imply that significant health benefits may still be obtained from additional pollution control measures in areas where PM levels have already been reduced. Copyright © 2016 Elsevier Ltd. All rights reserved.
-
Pickering, Amy J.; Boehm, Alexandria B.; Mwanjali, Mathew; Davis, Jennifer
2010-01-01
Effective handwashing with soap requires reliable access to water supplies. However, more than three billion persons do not have household-level access to piped water. This research addresses the challenge of improving hand hygiene within water-constrained environments. The antimicrobial efficacy of alcohol-based hand sanitizer, a waterless hand hygiene product, was evaluated and compared with handwashing with soap and water in field conditions in Dar es Salaam, Tanzania. Hand sanitizer use by mothers resulted in 0.66 and 0.64 log reductions per hand of Escherichia coli and fecal streptococci, respectively. In comparison, handwashing with soap resulted in 0.50 and 0.25 log reductions per hand of E. coli and fecal streptococci, respectively. Hand sanitizer was significantly better than handwashing with respect to reduction in levels of fecal streptococci (P = 0.01). The feasibility and health impacts of promoting hand sanitizer as an alternative hand hygiene option for water-constrained environments should be assessed. PMID:20134005
-
Iacumin, Lucilla; Manzano, Marisa; Comi, Giuseppe
2016-01-01
The anti-listerial activity of generally recognized as safe (GRAS) bacteriophage Listex P100 (phage P100) was demonstrated in broths and on the surface of slices of dry-cured ham against 5 strains or serotypes (i.e., Scott A, 1/2a, 1/2b, and 4b) of Listeria monocytogenes. In a broth model system, phage P100 at a concentration equal to or greater than 7 log PFU/mL completely inhibited 2 log CFU/cm2 or 3 log CFU/cm2 of L. monocytogenes growth at 30 °C. The temperature (4, 10, 20 °C) seemed to influence P100 activity; the best results were obtained at 4 °C. On dry-cured ham slices, a P100 concentration ranging from 5 to 8 log PFU/cm2 was required to obtain a significant reduction in L. monocytogenes. At 4, 10, and 20 °C, an inoculum of 8 log PFU/cm2 was required to completely eliminate 2 log L. monocytogenes/cm2 and to reach the absence in 25 g product according to USA food law. Conversely, it was impossible to completely eradicate L. monocytogenes with an inoculum of approximately of 3.0 and 4.0 log CFU/cm2 and with a P100 inoculum ranging from 1 to 7 log PFU/cm2. P100 remained stable on dry-cured ham slices over a 14-day storage period, with only a marginal loss of 0.2 log PFU/cm2 from an initial phage treatment of approximately 8 log PFU/cm2. Moreover, phage P100 eliminated free L. monocytogenes cells and biofilms on the machinery surfaces used for dry-cured ham production. These findings demonstrate that the GRAS bacteriophage Listex P100 at level of 8 log PFU/cm2 is listericidal and useful for reducing the L. monocytogenes concentration or eradicating the bacteria from dry-cured ham. PMID:27681898
-
Schlisselberg, Dov B; Kler, Edna; Kalily, Emmanuel; Kisluk, Guy; Karniel, Ohad; Yaron, Sima
2013-01-01
The consumer demand for fresh tasting, high quality, low salt, preservative-free meals which require minimal preparation time magnifies the safety concern and emphasizes the need to use innovative technologies for food processing. A modern technique to uniformly heat and cook foods is based on a combination of convection and controlled radio frequency (RF) energy. However any advantage conferred on meat cooked by this method would be lost if application of the technology results in decreased safety. Our main goal was to study the inactivation efficacy of this method of cooking against pathogens in ground meat in comparison to standard convection cooking. Meat balls were artificially inoculated with GFP expressing Escherichia coli, Salmonella Typhimurium and Listeria monocytogenes as well as spores of Bacillus cereus and Bacillus thuringiensis and cooked by convection heating (220°C, 40 min), by using energy generated from frequencies in the RF bandwidth (RF cooking, 7.5 min) or by combined heating (5.5 min), until the center temperature of each sample reached 73°C. The mean reductions in total indigenous bacteria obtained by RF and convection were 2.8 and 2.5 log CFU/g, respectively. Cooking of meat balls with convection reduced the E. coli population (8 log CFU/g) by 5.5 log CFU/g, whilst treatment with RF reduced E. coli population to undetectable levels. The mean reductions of S. Typhimurium obtained by RF and convection were 5.7 and 6.5 log CFU/g, respectively. The combined treatment reduced the Salmonella population to undetectable levels. In contrast, L. monocytogenes was poorly affected by RF cooking. The mean reduction of L. monocytogenes obtained by RF energy was 0.4 log CFU/g, while convection cooking resulted in undetectable levels. Interestingly, the combined treatment also resulted with undetectable levels of Listeria although time of cooking was reduced by 86%. One-step cooking had negligible effects on the Bacillus spores and therefore a 2-step treatment of RF or convection was applied. This 2-step treatment proved to be efficient with 4.5 log CFU/g reduction for both RF and convection. In conclusion, here we show that combination of RF with convection cooking resulted in similar or even better effects on selected foodborne pathogens compared to convection only, while the time required for safe cooking is cut down by up to 86%. The equal or better results in the levels of all investigated pathogens using RF with convection compared with convection only suggest that this technology looks promising and safe for ground beef cooking. Copyright © 2012 Elsevier B.V. All rights reserved.
-
75 FR 22713 - Implementation of Sanitary Food Transportation Act of 2005
Federal Register 2010, 2011, 2012, 2013, 2014
2010-04-30
... onto open boxes of produce below, and with juices from the raw poultry dripping out onto the pavement... treatments designed to 22)] facility requirement'') achieve a 5-log reduction are separated by time or space... recently contracted with Eastern Research Group, Inc. (ERG) to undertake a study designed to characterize...
-
Woody biomass size reduction with selective material orientation
Dooley, James H.; Lanning, David N.; Lanning, Christopher J.
2013-01-01
Roundwood logs from forests and energy plantations must be chipped, ground, or otherwise comminuted into small particles prior to conversion to solid or liquid biofuels. Rotary veneer followed by cross-grain shearing is demonstrated to be a novel and low energy consuming method for primary breakdown of logs into a raw material having high transport and storage density. Processing of high moisture raw logs into 2.5 – 4.2 mm particles prior to drying or conversion consumes less than 20% of the energy required for achieving similar particle size with hammer mills while producing a more uniform particle shape and size. Asmore » a result, energy savings from the proposed method may reduce the comminution cost of woody feedstocks by more than half.« less
-
Risk-based enteric pathogen reduction targets for non-potable ...
This paper presents risk-based enteric pathogen log reduction targets for non-potable and potable uses of a variety of alternative source waters (i.e., locally-collected greywater, roof runoff, and stormwater). A probabilistic Quantitative Microbial Risk Assessment (QMRA) was used to derive the pathogen log10 reduction targets (LRTs) that corresponded with an infection risk of either 10−4 per person per year (ppy) or 10−2 ppy. The QMRA accounted for variation in pathogen concentration and sporadic pathogen occurrence (when data were available) in source waters for reference pathogens in the genera Rotavirus, Mastadenovirus (human adenoviruses), Norovirus, Campylobacter, Salmonella, Giardia and Cryptosporidium. Non-potable uses included indoor use (for toilet flushing and clothes washing) with occasional accidental ingestion of treated non-potable water (or cross-connection with potable water), and unrestricted irrigation for outdoor use. Various exposure scenarios captured the uncertainty from key inputs, i.e., the pathogen concentration in source water; the volume of water ingested; and for the indoor use, the frequency of and the fraction of the population exposed to accidental ingestion. Both potable and non-potable uses required pathogen treatment for the selected waters and the LRT was generally greater for potable use than non-potable indoor use and unrestricted irrigation. The difference in treatment requirements among source waters was driven by the
-
Compendium of Dental Residents’ Research Project and Literature Reviews - 1991.
1992-04-01
4-log1 0 (99.99%) reduction of any of the microorgan- isms under the test conditions. Sporicidin and 0.525% sodium hypochlorite were able to effect a...4-log1 0 reduction against S. aureus only. Impresept and 5.25% sodium hypochlorite did achieve a 4-log10 reduction in bacterial counts in all cases...alginate impressions is currently unknown and warrants investigation. Full strength (5.25%) sodium hypochlorite was effective in the shortest contact time (1
-
Fuls, Janice L.; Rodgers, Nancy D.; Fischler, George E.; Howard, Jeanne M.; Patel, Monica; Weidner, Patrick L.; Duran, Melani H.
2008-01-01
Antimicrobial hand soaps provide a greater bacterial reduction than nonantimicrobial soaps. However, the link between greater bacterial reduction and a reduction of disease has not been definitively demonstrated. Confounding factors, such as compliance, soap volume, and wash time, may all influence the outcomes of studies. The aim of this work was to examine the effects of wash time and soap volume on the relative activities and the subsequent transfer of bacteria to inanimate objects for antimicrobial and nonantimicrobial soaps. Increasing the wash time from 15 to 30 seconds increased reduction of Shigella flexneri from 2.90 to 3.33 log10 counts (P = 0.086) for the antimicrobial soap, while nonantimicrobial soap achieved reductions of 1.72 and 1.67 log10 counts (P > 0.6). Increasing soap volume increased bacterial reductions for both the antimicrobial and the nonantimicrobial soaps. When the soap volume was normalized based on weight (∼3 g), nonantimicrobial soap reduced Serratia marcescens by 1.08 log10 counts, compared to the 3.83-log10 reduction caused by the antimicrobial soap (P < 0.001). The transfer of Escherichia coli to plastic balls following a 15-second hand wash with antimicrobial soap resulted in a bacterial recovery of 2.49 log10 counts, compared to the 4.22-log10 (P < 0.001) bacterial recovery on balls handled by hands washed with nonantimicrobial soap. This indicates that nonantimicrobial soap was less active and that the effectiveness of antimicrobial soaps can be improved with longer wash time and greater soap volume. The transfer of bacteria to objects was significantly reduced due to greater reduction in bacteria following the use of antimicrobial soap. PMID:18441107
-
Fuls, Janice L; Rodgers, Nancy D; Fischler, George E; Howard, Jeanne M; Patel, Monica; Weidner, Patrick L; Duran, Melani H
2008-06-01
Antimicrobial hand soaps provide a greater bacterial reduction than nonantimicrobial soaps. However, the link between greater bacterial reduction and a reduction of disease has not been definitively demonstrated. Confounding factors, such as compliance, soap volume, and wash time, may all influence the outcomes of studies. The aim of this work was to examine the effects of wash time and soap volume on the relative activities and the subsequent transfer of bacteria to inanimate objects for antimicrobial and nonantimicrobial soaps. Increasing the wash time from 15 to 30 seconds increased reduction of Shigella flexneri from 2.90 to 3.33 log(10) counts (P = 0.086) for the antimicrobial soap, while nonantimicrobial soap achieved reductions of 1.72 and 1.67 log(10) counts (P > 0.6). Increasing soap volume increased bacterial reductions for both the antimicrobial and the nonantimicrobial soaps. When the soap volume was normalized based on weight (approximately 3 g), nonantimicrobial soap reduced Serratia marcescens by 1.08 log(10) counts, compared to the 3.83-log(10) reduction caused by the antimicrobial soap (P < 0.001). The transfer of Escherichia coli to plastic balls following a 15-second hand wash with antimicrobial soap resulted in a bacterial recovery of 2.49 log(10) counts, compared to the 4.22-log(10) (P < 0.001) bacterial recovery on balls handled by hands washed with nonantimicrobial soap. This indicates that nonantimicrobial soap was less active and that the effectiveness of antimicrobial soaps can be improved with longer wash time and greater soap volume. The transfer of bacteria to objects was significantly reduced due to greater reduction in bacteria following the use of antimicrobial soap.
-
Post-wildfire logging hinders regeneration and increases fire risk.
Donato, D C; Fontaine, J B; Campbell, J L; Robinson, W D; Kauffman, J B; Law, B E
2006-01-20
We present data from a study of early conifer regeneration and fuel loads after the 2002 Biscuit Fire, Oregon, USA, with and without postfire logging. Natural conifer regeneration was abundant after the high-severity fire. Postfire logging reduced median regeneration density by 71%, significantly increased downed woody fuels, and thus increased short-term fire risk. Additional reduction of fuels is necessary for effective mitigation of fire risk. Postfire logging can be counterproductive to the goals of forest regeneration and fuel reduction.
-
Thermal Inactivation of Desiccation-Adapted Salmonella spp. in Aged Chicken Litter
Chen, Zhao; Diao, Junshu; Dharmasena, Muthu; Ionita, Claudia; Rieck, James
2013-01-01
Thermal inactivation of desiccation-adapted Salmonella spp. in aged chicken litter was investigated in comparison with that in a nonadapted control to examine potential cross-tolerance of desiccation-adapted cells to heat treatment. A mixture of four Salmonella serovars was inoculated into the finished compost with 20, 30, 40, and 50% moisture contents for a 24-h desiccation adaptation. Afterwards, the compost with desiccation-adapted cells was inoculated into the aged chicken litter with the same moisture content for heat treatments at 70, 75, 80, 85, and 150°C. Recovery media were used to allow heat-injured cells to resuscitate. A 5-log reduction in the number of the desiccation-adapted cells in aged chicken litter with a 20% moisture content required >6, >6, ∼4 to 5, and ∼3 to 4 h of exposure at 70, 75, 80, and 85°C, respectively. As a comparison, a 5-log reduction in the number of nonadapted control cells in the same chicken litter was achieved within ∼1.5 to 2, ∼1 to 1.5, ∼0.5 to 1, and <0.5 h at 70, 75, 80, and 85°C, respectively. The exposure time required to obtain a 5-log reduction in the number of desiccation-adapted cells gradually became shorter as temperature and moisture content were increased. At 150°C, desiccation-adapted Salmonella cells survived for 50 min in chicken litter with a 20% moisture content, whereas control cells were detectable by enrichment for only 10 min. Our results demonstrated that the thermal resistance of Salmonella in aged chicken litter was increased significantly when the cells were adapted to desiccation. This study also validated the effectiveness of thermal processing being used for producing chicken litter free of Salmonella contamination. PMID:24014540
-
Thermal inactivation of desiccation-adapted Salmonella spp. in aged chicken litter.
Chen, Zhao; Diao, Junshu; Dharmasena, Muthu; Ionita, Claudia; Jiang, Xiuping; Rieck, James
2013-11-01
Thermal inactivation of desiccation-adapted Salmonella spp. in aged chicken litter was investigated in comparison with that in a nonadapted control to examine potential cross-tolerance of desiccation-adapted cells to heat treatment. A mixture of four Salmonella serovars was inoculated into the finished compost with 20, 30, 40, and 50% moisture contents for a 24-h desiccation adaptation. Afterwards, the compost with desiccation-adapted cells was inoculated into the aged chicken litter with the same moisture content for heat treatments at 70, 75, 80, 85, and 150°C. Recovery media were used to allow heat-injured cells to resuscitate. A 5-log reduction in the number of the desiccation-adapted cells in aged chicken litter with a 20% moisture content required >6, >6, ∼4 to 5, and ∼3 to 4 h of exposure at 70, 75, 80, and 85°C, respectively. As a comparison, a 5-log reduction in the number of nonadapted control cells in the same chicken litter was achieved within ∼1.5 to 2, ∼1 to 1.5, ∼0.5 to 1, and <0.5 h at 70, 75, 80, and 85°C, respectively. The exposure time required to obtain a 5-log reduction in the number of desiccation-adapted cells gradually became shorter as temperature and moisture content were increased. At 150°C, desiccation-adapted Salmonella cells survived for 50 min in chicken litter with a 20% moisture content, whereas control cells were detectable by enrichment for only 10 min. Our results demonstrated that the thermal resistance of Salmonella in aged chicken litter was increased significantly when the cells were adapted to desiccation. This study also validated the effectiveness of thermal processing being used for producing chicken litter free of Salmonella contamination.
-
Evaluating UV-C LED disinfection performance and ...
This study evaluated ultraviolet (UV) light emitting diodes (LEDs) emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy at inactivating Escherichia. coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores; research included an evaluation of genomic damage. Inactivation by the LEDs was compared with the efficacy of conventional UV sources, the low-pressure (LP) and medium-pressure (MP) mercury vapor lamps. The work also calculated the electrical energy per order of reduction of the microorganisms by the five UV sources.For E. coli, all five UV sources yielded similar inactivation rates. For MS2 coliphage, the 260 nm LED was most effective. For HAdV2 and B. pumilus, the MP UV lamp was significantly more effective than the LP UV and UVC LED sources. When considering electrical energy per order of reduction, the LP UV lamp was the most efficient for E. coli and MS2, and the MPUV and LPUV were equally efficient for HAdV2 and B. pumilus spores. Among the UVC LEDs, the 280 nm LED unit required the least energy per log reduction of E. coli and HAdV2. The 280 nm and 260|280 nm LED units were equally efficient per log reduction of B. pumilus spores, and the 260 nm LED unit required the lowest energy per order of reduction of MS2 coliphage. The combination of the 260 nm and 280 nm UV LED wavelengths was also evaluated for potential synergistic effects. No dual-wavelength synergy was detected for inactivation of
-
Reduction of verotoxigenic Escherichia coli in production of fermented sausages.
Holck, Askild L; Axelsson, Lars; Rode, Tone Mari; Høy, Martin; Måge, Ingrid; Alvseike, Ole; L'abée-Lund, Trine M; Omer, Mohamed K; Granum, Per Einar; Heir, Even
2011-11-01
After a number of foodborne outbreaks of verotoxigenic Escherichia coli involving fermented sausages, some countries have imposed regulations on sausage production. For example, the US Food Safety and Inspection Service requires a 5 log(10) reduction of E. coli in fermented products. Such regulations have led to a number of studies on the inactivation of E. coli in fermented sausages by changing processing and post-processing conditions. Several factors influence the survival of E. coli such as pre-treatment of the meat, amount of NaCl, nitrite and lactic acid, water activity, pH, choice of starter cultures and addition of antimicrobial compounds. Also process variables like fermentation temperature and storage time play important roles. Though a large variety of different production processes of sausages exist, generally the reduction of E. coli caused by production is in the range 1-2 log(10). In many cases this may not be enough to ensure microbial food safety. By optimising ingredients and process parameters it is possible to increase E. coli reduction to some extent, but in some cases still other post process treatments may be required. Such treatments may be storage at ambient temperatures, specific heat treatments, high pressure processing or irradiation. HACCP analyses have identified the quality of the raw materials, low temperature in the batter when preparing the sausages and a rapid pH drop during fermentation as critical control points in sausage production. This review summarises the literature on the reduction verotoxigenic E. coli in production of fermented sausages. Copyright © 2011 Elsevier Ltd. All rights reserved.
-
USDA-ARS?s Scientific Manuscript database
Introduction: Current regulations require that juice processors effect a 5 log CFU/ml reduction of a target pathogen prior to distributing products. Whereas thermal pasteurization reduces the sensory characteristics of juice by altering flavor components, pulsed electric field (PEF) treatment may ...
-
Kohn, Tamar; Arnold, William A; Roberts, A Lynn
2006-07-01
Cross-correlations of rate constants between a system of interest and a better-defined one have become popular as a tool in studying transformations of organic pollutants. A slope of unity (if the correlation is conducted on a log-log basis) in such plots has been invoked as evidence of a common mechanism. To explore this notion, benzotrichloride and several of its substituted analogues were reacted with Cr(H2O)6(2+), an iron(II) porphyrin (iron meso-tetra(4-carboxyphenyl)porphine chloride, Fe(II)TCP), and granular iron. The first two reductants react with organohalides by dissociative inner sphere single-electron transfer, while mechanism(s) for organohalide reduction by granular iron are still debated. Apartfrom sterically hindered compounds, good correlations were obtained in comparing any two systems, although slopes (on a log-log basis) deviated from unity. We argue that a slope of unity is neither necessary nor sufficient evidence of a common mechanism. Overall rate constants may be composite entities, consisting in part of rate or equilibrium constants for adsorption onto surfaces or for precursor formation in solution; these components may differ between systems in their susceptibility to substituent effects. Cross-correlations may prove useful in predicting reactivity in the absence of steric effects, but additional evidence is required in deducing reaction mechanisms.
-
Al-Qadiri, Hamzah M; Ovissipour, Mahmoudreza; Al-Alami, Nivin; Govindan, Byju N; Shiroodi, Setareh Ghorban; Rasco, Barbara
2016-05-01
Bactericidal activity of neutral electrolyzed water (NEW), quaternary ammonium (QUAT), and lactic acid-based solutions was investigated using a manual spraying technique against Salmonella Typhimurium, Escherichia coli O157:H7, Campylobacter jejuni, Listeria monocytogenes and Staphylococcus aureus that were inoculated onto the surface of scarred polypropylene and wooden food cutting boards. Antimicrobial activity was also examined when using cutting boards in preparation of raw chopped beef, chicken tenders or salmon fillets. Viable counts of survivors were determined as log10 CFU/100 cm(2) within 0 (untreated control), 1, 3, and 5 min of treatment at ambient temperature. Within the first minute of treatment, NEW and QUAT solutions caused more than 3 log10 bacterial reductions on polypropylene surfaces whereas less than 3 log10 reductions were achieved on wooden surfaces. After 5 min of treatment, more than 5 log10 reductions were achieved for all bacterial strains inoculated onto polypropylene surfaces. Using NEW and QUAT solutions within 5 min reduced Gram-negative bacteria by 4.58 to 4.85 log10 compared to more than 5 log10 reductions in Gram-positive bacteria inoculated onto wooden surfaces. Lactic acid treatment was significantly less effective (P < 0.05) compared to NEW and QUAT treatments. A decline in antimicrobial effectiveness was observed (0.5 to <2 log10 reductions were achieved within the first minute) when both cutting board types were used to prepare raw chopped beef, chicken tenders or salmon fillets. © 2016 Institute of Food Technologists®
-
Zhou, Zijin; Zuber, Sophie; Cantergiani, Frédérique; Butot, Sophie; Li, Dan; Stroheker, Thomas; Devlieghere, Frank; Lima, Anthony; Piantini, Umberto; Uyttendaele, Mieke
2017-09-18
The efficacy of levulinic acid (LVA) in combination with sodium dodecyl sulfate (SDS) in removal of foodborne viruses, enteric bacterial pathogens and their surrogates on fresh strawberries was investigated. Inoculated strawberries were treated with potable water, sodium hypochlorite solution (50ppm), 0.5% LVA plus 0.5% SDS solution, and 5% LVA plus 2% SDS solution respectively for 2min, followed by spray-rinsing with potable water. Water washing removed at least 1.0-log of the tested viral and bacterial strains from the strawberries' surfaces. The 50ppm chlorine wash induced 3.4, 1.5 and 2.1-log reductions for hepatitis A virus (HAV), murine norovirus-1 (MNV-1) and MS2 bacteriophage, respectively. In comparison, the tested bacterial strains showed uniform reductions around 1.6-log CFU/ml. The 0.5% LVA plus 0.5% SDS wash induced 2.7, 1.4 and 2.4-log reductions for HAV, MNV-1 and MS2, which were comparable with the reductions induced by chlorine (P>0.05). For bacteria, over 2.0-log reductions were obtained for Enterococcus faecium, Listeria monocytogenes and Salmonella, while Escherichia coli O157:H7 and Escherichia coli P1 showed reductions of 1.9 and 1.8-log CFU/ml. Higher concentration of LVA plus SDS showed no significantly higher reductions (P>0.05). Sensory tests of washed strawberries and chemical residue analysis of LVA on strawberries after washing were also performed. In conclusion, this study demonstrates good performance of 0.5% LVA plus 0.5% SDS to reduce the levels of enteric pathogens if present on strawberries without altering taste and introducing chemical safety issues. Copyright © 2017 Elsevier B.V. All rights reserved.
-
Inactivation of Escherichia coli by ozone treatment of apple juice at different pH levels.
Patil, S; Valdramidis, V P; Cullen, P J; Frias, J; Bourke, P
2010-09-01
This research investigated the efficacy of gaseous ozone on the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in apple juice of a range of pH levels, using an ozone bubble column. The pH levels investigated were 3.0, 3.5, 4.0, 4.5 and 5.0. Apple juice inoculated with E. coli strains (10(6)CFU/mL) was treated with ozone gas at a flow rate of 0.12L/min and ozone concentration of 0.048 mg/min/mL for up to 18 min. Results show that inactivation kinetics of E. coli by ozone were affected by pH of the juice. The ozone treatment duration required for achieving a 5-log reduction was faster (4 min) at the lowest pH than at the highest pH (18 min) studied. The relationship between time required to achieve 5log reduction (t(5d)) and pH for both strains was described mathematically by two exponential equations. Ozone treatment appears to be an effective process for reducing bacteria in apple juice and the required applied treatment for producing a safe apple juice is dependant on its acidity level. Copyright 2010 Elsevier Ltd. All rights reserved.
-
A VLSI architecture for performing finite field arithmetic with reduced table look-up
NASA Technical Reports Server (NTRS)
Hsu, I. S.; Truong, T. K.; Reed, I. S.
1986-01-01
A new table look-up method for finding the log and antilog of finite field elements has been developed by N. Glover. In his method, the log and antilog of a field element is found by the use of several smaller tables. The method is based on a use of the Chinese Remainder Theorem. The technique often results in a significant reduction in the memory requirements of the problem. A VLSI architecture is developed for a special case of this new algorithm to perform finite field arithmetic including multiplication, division, and the finding of an inverse element in the finite field.
-
Elliott, M A; Stauber, C E; Koksal, F; DiGiano, F A; Sobsey, M D
2008-05-01
Point-of-use (POU) drinking water treatment technology enables those without access to safe water sources to improve the quality of their water by treating it in the home. One of the most promising emerging POU technologies is the biosand filter (BSF), a household-scale, intermittently operated slow sand filter. Over 500,000 people in developing countries currently use the filters to treat their drinking water. However, despite this successful implementation, there has been almost no systematic, process engineering research to substantiate the effectiveness of the BSF or to optimize its design and operation. The major objectives of this research were to: (1) gain an understanding of the hydraulic flow condition within the filter (2) characterize the ability of the BSF to reduce the concentration of enteric bacteria and viruses in water and (3) gain insight into the key parameters of filter operation and their effects on filter performance. Three 6-8 week microbial challenge experiments are reported herein in which local surface water was seeded with E. coli, echovirus type 12 and bacteriophages (MS2 and PRD-1) and charged to the filter daily. Tracer tests indicate that the BSF operated at hydraulic conditions closely resembling plug flow. The performance of the filter in reducing microbial concentrations was highly dependent upon (1) filter ripening over weeks of operation and (2) the daily volume charged to the filter. BSF performance was best when less than one pore volume (18.3-L in the filter design studied) was charged to the filter per day and this has important implications for filter design and operation. Enhanced filter performance due to ripening was generally observed after roughly 30 days. Reductions of E. coli B ranged from 0.3 log10 (50%) to 4 log10, with geometric mean reductions after at least 30 days of operation of 1.9 log10. Echovirus 12 reductions were comparable to those for E. coli B with a range of 1 log10 to >3 log10 and mean reductions after 30 days of 2.1 log10. Bacteriophage reductions were much lower, ranging from zero to 1.3 log10 (95%) with mean reductions of only 0.5 log10 (70%). These data indicate that virus reduction by BSF may differ substantially depending upon the specific viral agent.
-
In-vivo efficacy of hand sanitisers against feline calicivirus: a surrogate for norovirus.
Lages, S L S; Ramakrishnan, M A; Goyal, S M
2008-02-01
Hand disinfection is considered important in preventing the transmission of viruses, including norovirus. We investigated the virucidal efficacy of nine hand sanitisers (four alcohol-based sanitisers, three non-alcoholic sanitisers and two triclosan-containing antimicrobial liquid soaps) against feline calicivirus, a surrogate for norovirus, on artificially contaminated fingertips for 30 s and 2 min contact periods. Among alcohol-based sanitisers, a product containing 99.5% ethanol was more effective than those containing 62% ethanol, 70% isopropanol or 91% isopropanol. A log(10) virus reduction factor of 1.00-1.30 was achieved with 99.5% ethanol but those containing a lower alcohol concentration only achieved a log(10) reduction factor of
-
Hand hygiene regimens for the reduction of risk in food service environments.
Edmonds, Sarah L; McCormack, Robert R; Zhou, Sifang Steve; Macinga, David R; Fricker, Christopher M
2012-07-01
Pathogenic strains of Escherichia coli and human norovirus are the main etiologic agents of foodborne illness resulting from inadequate hand hygiene practices by food service workers. This study was conducted to evaluate the antibacterial and antiviral efficacy of various hand hygiene product regimens under different soil conditions representative of those in food service settings and assess the impact of product formulation on this efficacy. On hands contaminated with chicken broth containing E. coli, representing a moderate soil load, a regimen combining an antimicrobial hand washing product with a 70% ethanol advanced formula (EtOH AF) gel achieved a 5.22-log reduction, whereas a nonantimicrobial hand washing product alone achieved a 3.10log reduction. When hands were heavily soiled from handling ground beef containing E. coli, a wash-sanitize regimen with a 0.5% chloroxylenol antimicrobial hand washing product and the 70% EtOH AF gel achieved a 4.60-log reduction, whereas a wash-sanitize regimen with a 62% EtOH foam achieved a 4.11-log reduction. Sanitizing with the 70% EtOH AF gel alone was more effective than hand washing with a nonantimicrobial product for reducing murine norovirus (MNV), a surrogate for human norovirus, with 2.60- and 1.79-log reductions, respectively. When combined with hand washing, the 70% EtOH AF gel produced a 3.19-log reduction against MNV. A regimen using the SaniTwice protocol with the 70% EtOH AF gel produced a 4.04-log reduction against MNV. These data suggest that although the process of hand washing helped to remove pathogens from the hands, use of a wash-sanitize regimen was even more effective for reducing organisms. Use of a high-efficacy sanitizer as part of a wash-sanitize regimen further increased the efficacy of the regimen. The use of a well-formulated alcohol-based hand rub as part of a wash-sanitize regimen should be considered as a means to reduce risk of infection transmission in food service facilities.
-
Disinfection alternatives for contact surfaces and toys at child care centers.
Jimenez, Maribel; Martinez, Celida I; Chaidez, Cristobal
2010-12-01
Child care surfaces are vehicles for disease-causing organisms. Disinfectant procedures prevent microbial dispersion. This study reports the effectiveness of CITRUS Farm Edition® (CFE), Clorox® GreenWorks™ (CGW) and Clorox® Anywhere® (CA) against Salmonella Typhimurium and Staphylococcus aureus inoculated (1 ml of 9Log(10) CFU/ml) on a high chair and ball toy. Disinfectants were sprayed and bacteria recovered from surfaces by sponge method. Exposing an inoculated high chair to CA resulted in the highest reduction of S. aureus (3.92 Log(10)) and S. Typhimurium (3.22 Log(10)). CGW reduced S. aureus and S. Typhimurium by 2.84 and 2.12 Log(10) from the inoculated high chair, while the inoculated ball toy showed a 2.50 and 1.80 Log(10) reduction, respectively. CFE showed the lowest reduction with 1.42 and 1.53 Log(10) of S. aureus and S. Typhimurium from the inoculated ball toy. CA was the best disinfectant no matter which bacteria or surface was analyzed. Emphasis on the effectiveness of disinfectant products is needed to be included in child care center infection control programs.
-
The SWTR-LT2 Rule addresses the use of membranes that may be used to achieve credits for the reduction of Cryptosporidium. The LT2 Rule requires product-specific testing of membranes, considered an alternative filtration technology by the rule. LT2 Rule allows the product speci...
-
Validating Thermal Inactivation of Salmonella spp. in Fresh and Aged Chicken Litter
Kim, Jinkyung; Diao, Junshu; Shepherd, Marion W.; Singh, Randhir; Heringa, Spencer D.; Gong, Chao
2012-01-01
Our results revealed that a 7-log reduction of Salmonella can be achieved by exposing fresh chicken litter for 80.5 to 100.8, 78.4 to 93.1, and 44.1 to 63 min at 70, 75, and 80°C, respectively, depending on initial moisture contents. However, the aged chicken litter requires more heat treatment. PMID:22179246
-
King, Amanda M; Miller, Rhonda K; Castillo, Alejandro; Griffin, Davey B; Hardin, Margaret D
2012-09-01
Current industry chilling practices with and without the application of 2% L-lactic acid were compared for their effectiveness at reducing levels of Salmonella, Yersinia enterocolitica, and Campylobacter coli on pork variety meats. Pork variety meats (livers, intestines, hearts, and stomachs) were inoculated individually with one of the three pathogens and subjected to five different treatment combinations that included one or more of the following: water wash (25°C), lactic acid spray (2%, 40 to 50°C), chilling (4°C), and freezing (-15°C). Samples were analyzed before treatment, after each treatment step, and after 2, 4, and 6 months of frozen storage. Results showed that when a lactic acid spray was used in combination with water spray, immediate reductions were approximately 0.5 log CFU per sample of Salmonella, 0.8 log CFU per sample of Y. enterocolitica, and 1.1 log CFU per sample of C. coli. Chilling, both alone and in combination with spray treatments, had little effect on pathogens, while freezing resulted in additional 0.5-log CFU per sample reductions in levels of Salmonella and Y. enterocolitica, and an additional 1.0-log CFU per sample reduction in levels of C. coli. While reductions of at least 1 log CFU per sample were observed on variety meats treated with only a water wash and subsequently frozen, samples treated with lactic acid had greater additional reductions than those treated with only a water spray throughout frozen storage. The results of this study suggest that the use of lactic acid as a decontamination intervention, when used in combination with good manufacturing practices during processing, causes significant reductions in levels of Salmonella, Y. enterocolitica, and C. coli on pork variety meats.
-
Uppal, Kamaldeep K; Getty, Kelly J K; Boyle, Elizabeth A E; Harper, Nigel M; Lobaton-Sulabo, April Shayne S; Barry, Bruce
2012-01-01
The objective of our study was to determine effect of packaging method and storage time on reducing Listeria monocytogenes in shelf-stable meat snacks. Commercially available kippered beef steak strips and turkey tenders were dipped into a 5-strain L. monocytogenes cocktail, and dried at 23 °C until a water activity of 0.80 was achieved. Inoculated samples were packaged with 4 treatments: (1) vacuum, (2) nitrogen flushed with oxygen scavenger, (3) heat sealed with oxygen scavenger, and (4) heat sealed without oxygen scavenger. Samples were stored at 23 °C and evaluated for L. monocytogenes levels at 0, 24, 48, and 72 h. Initial levels (time 0) of L. monocytogenes were approximately 5.7 log CFU/cm² for steak and tenders. After 24 h of storage time, a 1 log CFU/cm² reduction of L. monocytogenes was observed for turkey tenders for all packaging treatments. After 48 h, turkey tenders showed >1 log CFU/cm² reduction of L. monocytogenes for all packaging treatments except for vacuum, where only 0.9 log CFU/cm² reduction was observed. After 72 h, reductions for all packaging treatments for turkey tenders ranged from 1.5 to 2.4 log CFU/cm². For kippered beef steak, there was no interaction between the packaging treatments and all storage times (P > 0.05) whereas, time was different (P <0.05). For kippered beef steak, there was 1 log reduction of L. monocytogenes at 24 and 48 h of storage times at 23 °C for all packaging treatments and a 2.1 log CFU/ cm² L. monocytogenes reduction at 72 h of storage time. Processors of kippered beef steak and turkey tenders could use a combination of vacuum or nitrogen-flushing or heat sealed with an oxygen scavenger packaging methods and a holding time of 24 h prior to shipping to reduce potential L. monocytogenes numbers by ≥1 log. However, processors should be encouraged to hold packaged product a minimum of 72 h to enhance the margin of safety for L. monocytogenes control. © 2011 Institute of Food Technologists®
-
Hwang, Cheng-An; Porto-Fett, Anna C S; Juneja, Vijay K; Ingham, Steven C; Ingham, Barbara H; Luchansky, John B
2009-02-28
This study quantified and modeled the survival of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella Typhimurium in soudjouk-style fermented sausage during fermentation, drying, and storage. Batter prepared from ground beef (20% fat), seasonings, starter culture, and dextrose was separately inoculated with a multi-strain mixture of each pathogen to an initial inoculum of ca. 6.5 log(10) CFU/g in the batter. The sausages were subsequently fermented at 24 degrees C with a relative humidity (RH) of 90% to 95% for 3 to 5 days to ca. pH 5.2, pH 4.9 or pH 4.6, then dried at 22 degrees C to a(w) 0.92, a(w) 0.89, or a(w) 0.86, respectively, and then stored at 4, 21, or 30 degrees C for up to 60 days. Lethality of the three pathogens was modeled as a function of pH, a(w) and/or storage temperature. During fermentation to pH 5.2 to pH 4.6, cell reductions ranged from 0 to 0.9 log(10) CFU/g for E. coli O157:H7, 0.1 to 0.5 log(10) CFU/g for L. monocytogenes, and 0 to 2.2 log(10) CFU/g for S. Typhimurium. Subsequent drying of sausages of pH 5.2 to pH 4.6 at 22 degrees C with 80% to 85% RH for 3 to 7 days to a(w) of 0.92 to a(w) 0.86 resulted in additional reductions that ranged from 0 to 3.5 log(10) CFU/g for E. coli O157:H7, 0 to 0.4 log(10) CFU/g for L. monocytogenes, and 0.3 to 2.4 log(10) CFU/g for S. Typhimurium. During storage at 4, 21, or 30 degrees C the reduction rates of the three pathogens were generally higher (p<0.05) in sausages with lower pH and lower a(w) that were stored at higher temperatures. Polynomial equations were developed to describe the inactivation of the three pathogens during fermentation, drying, and storage. The applicability of the resulting models for fermented sausage was evaluated by comparing model predictions with published data. Pathogen reductions estimated by the models for E. coli O157:H7 and S. Typhimurium were comparable to 67% and 73% of published data, respectively. Due to limited published data for L. monocytogenes, the models for L. monocytogenes would need additional validations. Results of pathogen reductions from this study may be used as a reference to assist manufacturers of soudjouk-style sausages to adopt manufacturing processes that meet the regulatory requirements. The resulting models may also be used for estimating the survival of E. coli O157:H7 and S. Typhimurium in other similar fermented sausage during fermentation and storage.
-
Microbial Removals by a Novel Biofilter Water Treatment System
Wendt, Christopher; Ives, Rebecca; Hoyt, Anne L.; Conrad, Ken E.; Longstaff, Stephanie; Kuennen, Roy W.; Rose, Joan B.
2015-01-01
Two point-of-use drinking water treatment systems designed using a carbon filter and foam material as a possible alternative to traditional biosand systems were evaluated for removal of bacteria, protozoa, and viruses. Two configurations were tested: the foam material was positioned vertically around the carbon filter in the sleeve unit or horizontally in the disk unit. The filtration systems were challenged with Cryptosporidium parvum, Raoultella terrigena, and bacteriophages P22 and MS2 before and after biofilm development to determine average log reduction (ALR) for each organism and the role of the biofilm. There was no significant difference in performance between the two designs, and both designs showed significant levels of removal (at least 4 log10 reduction in viruses, 6 log10 for protozoa, and 8 log10 for bacteria). Removal levels meet or exceeded Environmental Protection Agency (EPA) standards for microbial purifiers. Exploratory test results suggested that mature biofilm formation contributed 1–2 log10 reductions. Future work is recommended to determine field viability. PMID:25758649
-
Wolfe, Marlene K; Gallandat, Karin; Daniels, Kyle; Desmarais, Anne Marie; Scheinman, Pamela; Lantagne, Daniele
2017-01-01
To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94-3.01 log reduction in E. coli concentration without, and 2.18-3.34 with, soil load; and a 2.44-3.06 log reduction in Phi6 without, and 2.71-3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28-4.77 log reduction in remaining E. coli without, and 0.21-4.49 with, soil load and a 1.26-2.02 log reduction in Phi6 without, and 1.30-2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001). Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence.
-
Ravyts, Frédéric; Barbuti, Silvana; Frustoli, Maria Angela; Parolari, Giovanni; Saccani, Giovanna; De Vuyst, Luc; Leroy, Frédéric
2008-09-01
Application of bacteriocin-producing starter cultures of lactic acid bacteria in fermented sausage production contributes to food safety. This is sometimes hampered by limited efficacy in situ and by uncertainty about strain dependency and universal applicability for different sausage types. In the present study, a promising antilisterial-bacteriocin producer, Lactobacillus sakei CTC 494, was applied as a coculture in addition to commercial fermentative starters in different types of dry-fermented sausages. The strain was successful in both Belgian-type sausage and Italian salami that were artificially contaminated with about 3.5 log CFU g(-1) of Listeria monocytogenes. After completion of the production process, this led to listerial reductions of up to 1.4 and 0.6 log CFU g(-1), respectively. In a control sausage, containing only the commercial fermentative starter, the reduction was limited to 0.8 log CFU g(-1) for the Belgian-type recipe, where pH decreased from 5.9 to 4.9, whereas an increase of 0.2 log CFU g(-1) was observed for Italian salami, in which the pH rose from 5.7 to 5.9 after an initial decrease to pH 5.3. In a Cacciatore recipe inoculated with 5.5 log CFU g(-1) of L. monocytogenes and in the presence of L. sakei CTC 494, there was a listerial reduction of 1.8 log CFU g(-1) at the end of the production process. This was superior to the effect obtained with the control sausage (0.8 log CFU g(-1)). Two commercial antilisterial cultures yielded reductions of 1.2 and 1.5 log CFU g(-1). Moreover, repetitive DNA sequence-based PCR fingerprinting demonstrated the competitive superiority of L. sakei CTC 494.
-
Tertiary treatment using microfiltration and UV disinfection for water reclamation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jolis, D.; Hirano, R.; Pitt, P.
Microfiltration and UV disinfection are two alternative technologies for water reclamation. The results of a pilot study combining these two processes are presented. In addition to producing filtrate turbidites averaging 0.06 nephelometric turbidity units, microfiltration was an effective barrier to pathogens, demonstrating average log reductions of 4.5 for total coliforms and 2.9 for MS2 bacteriophage. Ultraviolet disinfection following microfiltration reliably met the California Wastewater Reclamation Criteria (Title 22) total coliform standard of 2.2 colony-forming units/100 mL at a UV dose of 450 J/m{sup 2}. The MS2 bacteriophage standard, which requires a 5-log reduction, was achieved by microfiltration and a UVmore » dose of 880 J/m{sup 2}. A model of the kinetics of inactivation of MS2 bacteriophage was used in further analysis of disinfection data. The model indicated that considerable backmixing occurred in the pilot UV disinfection unit, and observed UV doses could be reduced with improved hydraulics.« less
-
Quantitative evaluation of dermatological antiseptics.
Leitch, C S; Leitch, A E; Tidman, M J
2015-12-01
Topical antiseptics are frequently used in dermatological management, yet evidence for the efficacy of traditional generic formulations is often largely anecdotal. We tested the in vitro bactericidal activity of four commonly used topical antiseptics against Staphylococcus aureus, using a modified version of the European Standard EN 1276, a quantitative suspension test for evaluation of the bactericidal activity of chemical disinfectants and antiseptics. To meet the standard for antiseptic effectiveness of EN 1276, at least a 5 log10 reduction in bacterial count within 5 minutes of exposure is required. While 1% benzalkonium chloride and 6% hydrogen peroxide both achieved a 5 log10 reduction in S. aureus count, neither 2% aqueous eosin nor 1 : 10 000 potassium permanganate showed significant bactericidal activity compared with control at exposure periods of up to 1 h. Aqueous eosin and potassium permanganate may have desirable astringent properties, but these results suggest they lack effective antiseptic activity, at least against S. aureus. © 2015 British Association of Dermatologists.
-
Carty, Neal; Wibaux, Anne; Ward, Colleen; Paulson, Daryl S.; Johnson, Peter
2014-01-01
Objectives To evaluate the antimicrobial activity of a new, transparent composite film dressing, whose adhesive contains chlorhexidine gluconate (CHG), against the native microflora present on human skin. Methods CHG-containing adhesive film dressings and non-antimicrobial control film dressings were applied to the skin on the backs of healthy human volunteers without antiseptic preparation. Dressings were removed 1, 4 or 7 days after application. The bacterial populations underneath were measured by quantitative cultures (cylinder-scrub technique) and compared with one another as a function of time. Results The mean baseline microflora recovery was 3.24 log10 cfu/cm2. The mean log reductions from baseline measured from underneath the CHG-containing dressings were 0.87, 0.78 and 1.30 log10 cfu/cm2 on days 1, 4 and 7, respectively, compared with log reductions of 0.67, −0.87 and −1.29 log10 cfu/cm2 from underneath the control film dressings. There was no significant difference between the log reductions of the two treatments on day 1, but on days 4 and 7 the log reduction associated with the CHG adhesive was significantly higher than that associated with the control adhesive. Conclusions The adhesive containing CHG was associated with a sustained antimicrobial effect that was not present in the control. Incorporating the antimicrobial into the adhesive layer confers upon it bactericidal properties in marked contrast to the non-antimicrobial adhesive, which contributed to bacterial proliferation when the wear time was ≥4 days. PMID:24722839
-
Carty, Neal; Wibaux, Anne; Ward, Colleen; Paulson, Daryl S; Johnson, Peter
2014-08-01
To evaluate the antimicrobial activity of a new, transparent composite film dressing, whose adhesive contains chlorhexidine gluconate (CHG), against the native microflora present on human skin. CHG-containing adhesive film dressings and non-antimicrobial control film dressings were applied to the skin on the backs of healthy human volunteers without antiseptic preparation. Dressings were removed 1, 4 or 7 days after application. The bacterial populations underneath were measured by quantitative cultures (cylinder-scrub technique) and compared with one another as a function of time. The mean baseline microflora recovery was 3.24 log10 cfu/cm(2). The mean log reductions from baseline measured from underneath the CHG-containing dressings were 0.87, 0.78 and 1.30 log10 cfu/cm(2) on days 1, 4 and 7, respectively, compared with log reductions of 0.67, -0.87 and -1.29 log10 cfu/cm(2) from underneath the control film dressings. There was no significant difference between the log reductions of the two treatments on day 1, but on days 4 and 7 the log reduction associated with the CHG adhesive was significantly higher than that associated with the control adhesive. The adhesive containing CHG was associated with a sustained antimicrobial effect that was not present in the control. Incorporating the antimicrobial into the adhesive layer confers upon it bactericidal properties in marked contrast to the non-antimicrobial adhesive, which contributed to bacterial proliferation when the wear time was ≥4 days. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.
-
USDA-ARS?s Scientific Manuscript database
Current FDA regulations require that juice processors effect a 5 log CFU/ml reduction of a target pathogen prior to distributing products. Whereas thermal pasteurization reduces the sensory characteristics of juice by altering flavor components, pulsed electric field (PEF) treatment can be conducte...
-
Kanellopoulos, Anastasios John
2009-09-01
The safety and efficacy of corneal collagen cross-linking (CXL) and topography-guided photorefractive keratectomy (PRK) using a different sequence and timing were evaluated in consecutive keratoconus cases. This study included a total of 325 eyes with keratoconus. Eyes were divided into two groups. The first group (n=127 eyes) underwent CXL with subsequent topography-guided PRK performed 6 months later (sequential group) and the second group (n=198 eyes) underwent CXL and PRK in a combined procedure on the same day (simultaneous group). Statistical differences were examined for pre- to postoperative changes in uncorrected (UCVA, logMAR) and best-spectacle-corrected visual acuity (BSCVA, logMAR), manifest refraction spherical equivalent (MRSE), keratometry (K), topography, central corneal thickness, endothelial cell count, corneal haze, and ectatic progression. Mean follow-up was 36+/-18 months (range: 24 to 68 months). At last follow-up in the sequential group, the mean UCVA improved from 0.9+/-0.3 logMAR to 0.49+/-0.25 logMAR, and mean BSCVA from 0.41+/-0.25 logMAR to 0.16+/-0.22 logMAR. Mean reduction in spherical equivalent refraction was 2.50+/-1.20 diopters (D), mean haze score was 1.2+/-0.5, and mean reduction in K was 2.75+/-1.30 D. In the simultaneous group, mean UCVA improved from 0.96+/-0.2 logMAR to 0.3+/-0.2 logMAR, and mean BSCVA from 0.39+/-0.3 logMAR to 0.11+/-0.16 logMAR. Mean reduction in spherical equivalent refraction was 3.20+/-1.40 D, mean haze score was 0.5+/-0.3, and mean reduction in K was 3.50+/-1.3 D. Endothelial cell count preoperatively and at last follow-up was unchanged (P<.05) in both groups. Statistically, the simultaneous group did better (P<.05) in all fields evaluated, with improvement in UCVA and BSCVA, a greater mean reduction in spherical equivalent refraction and keratometry, and less corneal haze. Same-day simultaneous topography-guided PRK and CXL appears to be superior to sequential CXL with later PRK in the visual rehabilitation of progressing keratoconus. Copyright 2009, SLACK Incorporated.
-
Bozkurt, Hayriye; D'Souza, Doris H; Davidson, P Michael
2014-05-01
Hepatitis A virus (HAV) is a food-borne enteric virus responsible for outbreaks of hepatitis associated with shellfish consumption. The objectives of this study were to determine the thermal inactivation behavior of HAV in blue mussels, to compare the first-order and Weibull models to describe the data, to calculate Arrhenius activation energy for each model, and to evaluate model efficiency by using selected statistical criteria. The times required to reduce the population by 1 log cycle (D-values) calculated from the first-order model (50 to 72°C) ranged from 1.07 to 54.17 min for HAV. Using the Weibull model, the times required to destroy 1 log unit (tD = 1) of HAV at the same temperatures were 1.57 to 37.91 min. At 72°C, the treatment times required to achieve a 6-log reduction were 7.49 min for the first-order model and 8.47 min for the Weibull model. The z-values (changes in temperature required for a 90% change in the log D-values) calculated for HAV were 15.88 ± 3.97°C (R(2), 0.94) with the Weibull model and 12.97 ± 0.59°C (R(2), 0.93) with the first-order model. The calculated activation energies for the first-order model and the Weibull model were 165 and 153 kJ/mol, respectively. The results revealed that the Weibull model was more appropriate for representing the thermal inactivation behavior of HAV in blue mussels. Correct understanding of the thermal inactivation behavior of HAV could allow precise determination of the thermal process conditions to prevent food-borne viral outbreaks associated with the consumption of contaminated mussels.
-
Pathogen Reduction in Human Plasma Using an Ultrashort Pulsed Laser
Tsen, Shaw-Wei D.; Kingsley, David H.; Kibler, Karen; Jacobs, Bert; Sizemore, Sara; Vaiana, Sara M.; Anderson, Jeanne; Tsen, Kong-Thon; Achilefu, Samuel
2014-01-01
Pathogen reduction is a viable approach to ensure the continued safety of the blood supply against emerging pathogens. However, the currently licensed pathogen reduction techniques are ineffective against non-enveloped viruses such as hepatitis A virus, and they introduce chemicals with concerns of side effects which prevent their widespread use. In this report, we demonstrate the inactivation of both enveloped and non-enveloped viruses in human plasma using a novel chemical-free method, a visible ultrashort pulsed laser. We found that laser treatment resulted in 2-log, 1-log, and 3-log reductions in human immunodeficiency virus, hepatitis A virus, and murine cytomegalovirus in human plasma, respectively. Laser-treated plasma showed ≥70% retention for most coagulation factors tested. Furthermore, laser treatment did not alter the structure of a model coagulation factor, fibrinogen. Ultrashort pulsed lasers are a promising new method for chemical-free, broad-spectrum pathogen reduction in human plasma. PMID:25372037
-
Harding, Alexander S.; Schwab, Kellogg J.
2012-01-01
We investigated the use of psoralens and limes to enhance solar disinfection of water (SODIS) using an UV lamp and natural sunlight experiments. SODIS conditions were replicated using sunlight, 2 L polyethylene terephthalate (PET) bottles, and tap water with Escherichia coli, MS2 bacteriophage, and murine norovirus (MNV). Psoralens and lime acidity both interact synergistically with UV radiation to accelerate inactivation of microbes. Escherichia coli was ablated > 6.1 logs by SODIS + Lime Slurry and 5.6 logs by SODIS + Lime Juice in 30-minute solar exposures, compared with a 1.5 log reduction with SODIS alone (N = 3; P < 0.001). MS2 was inactivated > 3.9 logs by SODIS + Lime Slurry, 1.9 logs by SODIS + Lime Juice, and 1.4 logs by SODIS in 2.5-hour solar exposures (N = 3; P < 0.05). MNV was resistant to SODIS, with < 2 log reductions after 6 hours. Efficacy of SODIS against human norovirus should be investigated further. PMID:22492137
-
Pang, Liping; Close, Murray; Goltz, Mark; Noonan, Mike; Sinton, Lester
2005-04-01
Filtration of Bacillus subtilis spores and the F-RNA phage MS2 (MS2) on a field scale in a coarse alluvial gravel aquifer was evaluated from the authors' previously published data. An advection-dispersion model that is coupled with first-order attachment kinetics was used in this study to interpret microbial concentration vs. time breakthrough curves (BTC) at sampling wells. Based on attachment rates (katt) that were determined by applying the model to the breakthrough data, filter factors (f) were calculated and compared with f values estimated from the slopes of log (cmax/co) vs. distance plots. These two independent approaches resulted in nearly identical filter factors, suggesting that both approaches are useful in determining reductions in microbial concentrations over transport distance. Applying the graphic approach to analyse spatial data, we have also estimated the f values for different aquifers using information provided by some other published field studies. The results show that values of f, in units of log (cmax/co) m(-1), are consistently in the order of 10(-2) for clean coarse gravel aquifers, 10(-3) for contaminated coarse gravel aquifers, and generally 10(-1) for sandy fine gravel aquifers and river and coastal sand aquifers. For each aquifer category, the f values for bacteriophages and bacteria are in the same order-of-magnitude. The f values estimated in this study indicate that for every one-log reduction in microbial concentration in groundwater, it requires a few tens of meters of travel in clean coarse gravel aquifers, but a few hundreds of meters in contaminated coarse gravel aquifers. In contrast, a one-log reduction generally only requires a few meters of travel in sandy fine gravel aquifers and sand aquifers. Considering the highest concentration in human effluent is in the order of 10(4) pfu/l for enteroviruses and 10(6) cfu/100 ml for faecal coliform bacteria, a 7-log reduction in microbial concentration would comply with the drinking water standards for the downgradient wells under natural gradient conditions. Based on the results of this study, a 7-log reduction would require 125-280 m travel in clean coarse gravel aquifers, 1.7-3.9 km travel in contaminated coarse gravel aquifers, 33-61 m travel in clean sandy fine gravel aquifers, 33-129 m travel in contaminated sandy fine gravel aquifers, and 37-44 m travel in contaminated river and coastal sand aquifers. These recommended setback distances are for a worst-case scenario, assuming direct discharge of raw effluent into the saturated zone of an aquifer. Filtration theory was applied to calculate collision efficiency (alpha) from model-derived attachment rates (katt), and the results are compared with those reported in the literature. The calculated alpha values vary by two orders-of-magnitude, depending on whether collision efficiency is estimated from the effective particle size (d10) or the mean particle size (d50). Collision efficiency values for MS-2 are similar to those previously reported in the literature (e.g. ) [DeBorde, D.C., Woessner, W.W., Kiley, QT., Ball, P., 1999. Rapid transport of viruses in a floodplain aquifer. Water Res. 33 (10), 2229-2238]. However, the collision efficiency values calculated for Bacillus subtilis spores were unrealistic, suggesting that filtration theory is not appropriate for theoretically estimating filtration capacity for poorly sorted coarse gravel aquifer media. This is not surprising, as filtration theory was developed for uniform sand filters and does not consider particle size distribution. Thus, we do not recommend the use of filtration theory to estimate the filter factor or setback distances. Either of the methods applied in this work (BTC or concentration vs. distance analyses), which takes into account aquifer heterogeneities and site-specific conditions, appear to be most useful in determining filter factors and setback distances.
-
NASA Astrophysics Data System (ADS)
Pang, Liping; Close, Murray; Goltz, Mark; Noonan, Mike; Sinton, Lester
2005-04-01
Filtration of Bacillus subtilis spores and the F-RNA phage MS2 (MS2) on a field scale in a coarse alluvial gravel aquifer was evaluated from the authors' previously published data. An advection-dispersion model that is coupled with first-order attachment kinetics was used in this study to interpret microbial concentration vs. time breakthrough curves (BTC) at sampling wells. Based on attachment rates ( katt) that were determined by applying the model to the breakthrough data, filter factors ( f) were calculated and compared with f values estimated from the slopes of log ( cmax/ co) vs. distance plots. These two independent approaches resulted in nearly identical filter factors, suggesting that both approaches are useful in determining reductions in microbial concentrations over transport distance. Applying the graphic approach to analyse spatial data, we have also estimated the f values for different aquifers using information provided by some other published field studies. The results show that values of f, in units of log ( cmax/ co) m -1, are consistently in the order of 10 -2 for clean coarse gravel aquifers, 10 -3 for contaminated coarse gravel aquifers, and generally 10 -1 for sandy fine gravel aquifers and river and coastal sand aquifers. For each aquifer category, the f values for bacteriophages and bacteria are in the same order-of-magnitude. The f values estimated in this study indicate that for every one-log reduction in microbial concentration in groundwater, it requires a few tens of meters of travel in clean coarse gravel aquifers, but a few hundreds of meters in contaminated coarse gravel aquifers. In contrast, a one-log reduction generally only requires a few meters of travel in sandy fine gravel aquifers and sand aquifers. Considering the highest concentration in human effluent is in the order of 10 4 pfu/l for enteroviruses and 10 6 cfu/100 ml for faecal coliform bacteria, a 7-log reduction in microbial concentration would comply with the drinking water standards for the downgradient wells under natural gradient conditions. Based on the results of this study, a 7-log reduction would require 125-280 m travel in clean coarse gravel aquifers, 1.7-3.9 km travel in contaminated coarse gravel aquifers, 33-61 m travel in clean sandy fine gravel aquifers, 33-129 m travel in contaminated sandy fine gravel aquifers, and 37-44 m travel in contaminated river and coastal sand aquifers. These recommended setback distances are for a worst-case scenario, assuming direct discharge of raw effluent into the saturated zone of an aquifer. Filtration theory was applied to calculate collision efficiency ( α) from model-derived attachment rates ( katt), and the results are compared with those reported in the literature. The calculated α values vary by two orders-of-magnitude, depending on whether collision efficiency is estimated from the effective particle size ( d10) or the mean particle size ( d50). Collision efficiency values for MS-2 are similar to those previously reported in the literature (e.g. DeBorde et al., 1999) [DeBorde, D.C., Woessner, W.W., Kiley, QT., Ball, P., 1999. Rapid transport of viruses in a floodplain aquifer. Water Res. 33 (10), 2229-2238]. However, the collision efficiency values calculated for Bacillus subtilis spores were unrealistic, suggesting that filtration theory is not appropriate for theoretically estimating filtration capacity for poorly sorted coarse gravel aquifer media. This is not surprising, as filtration theory was developed for uniform sand filters and does not consider particle size distribution. Thus, we do not recommend the use of filtration theory to estimate the filter factor or setback distances. Either of the methods applied in this work (BTC or concentration vs. distance analyses), which takes into account aquifer heterogeneities and site-specific conditions, appear to be most useful in determining filter factors and setback distances.
-
Point-of-use water disinfection using ultraviolet and visible light-emitting diodes.
Lui, Gough Yumu; Roser, David; Corkish, Richard; Ashbolt, Nicholas J; Stuetz, Richard
2016-05-15
Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270-740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6h. Five log10 and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log10s E. coli and E. faecalis over the 6h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for >3-log10 reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5-2.5 fold at 365-455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work. Copyright © 2016 Elsevier B.V. All rights reserved.
-
Potential impact of easing the log export restriction on the Tongass National Forest.
David R. Darr
1978-01-01
The potential of higher revenues in the log export market is constrained by possible reductions in prices associated with expanded supplies in the Japanese log market. Expanded log exports from the Tongass National Forest might force adjustments by existing cantmills, even under a partial easing of the export restriction.
-
Microbial removals by a novel biofilter water treatment system.
Wendt, Christopher; Ives, Rebecca; Hoyt, Anne L; Conrad, Ken E; Longstaff, Stephanie; Kuennen, Roy W; Rose, Joan B
2015-04-01
Two point-of-use drinking water treatment systems designed using a carbon filter and foam material as a possible alternative to traditional biosand systems were evaluated for removal of bacteria, protozoa, and viruses. Two configurations were tested: the foam material was positioned vertically around the carbon filter in the sleeve unit or horizontally in the disk unit. The filtration systems were challenged with Cryptosporidium parvum, Raoultella terrigena, and bacteriophages P22 and MS2 before and after biofilm development to determine average log reduction (ALR) for each organism and the role of the biofilm. There was no significant difference in performance between the two designs, and both designs showed significant levels of removal (at least 4 log10 reduction in viruses, 6 log10 for protozoa, and 8 log10 for bacteria). Removal levels meet or exceeded Environmental Protection Agency (EPA) standards for microbial purifiers. Exploratory test results suggested that mature biofilm formation contributed 1-2 log10 reductions. Future work is recommended to determine field viability. © The American Society of Tropical Medicine and Hygiene.
-
Bonjoch, X; Blanch, A R
2009-04-01
The composition of the most abundant facultative anaerobic bacteria populations [faecal coliforms (FC) and enterococci (ENT)] in sludge can be modified after different treatments. These involve the disposal or reuse of sludge and include: anaerobic digesters, incineration, composting, pasteurization and lime treatments. In this study, three treatment types (mesophilic anaerobic digestion, composting and pasteurization) were compared in terms of their ability to reduce both bacterial populations. The diversity and any changes in composition of main phenotypic groups for both populations were also analyzed. Mesophilic anaerobic digestion (MAD) was carried out at 35 degrees C for 20 days. Digested sludge was then dehydrated by centrifugation at 2,500 rpm. Composting (COM) was performed at 55 degrees C with windrow phases. Pasteurization was assayed at 60 degrees C for 90 min (P60), at 80 degrees C for 60 min (P80). A 1-1.5 log unit reduction was observed for FC, and 1 log unit reduction was noted for ENT by MAD treatment. In composting, this reduction proved higher for FC than for ENT (6 log and 3-4 log units, respectively). Optimal pasteurization was obtained at 80 degrees C for 60 min, resulting in a 5 log unit reduction for FC and a 2 log unit reduction for ENT. High diversity indices (Di) for both bacterial populations were detected both before and after implementation of the different treatments. Analyses of the population's similarity provided that FC were diverse both before and after COM, P60 and P80 treatments. However, no differences were observed on the composition of ENT populations after the different treatments assayed.
-
Impact of different tongue cleaning methods on the bacterial load of the tongue dorsum.
Bordas, Alice; McNab, Rod; Staples, Angela M; Bowman, Jim; Kanapka, Joe; Bosma, Marylynn P
2008-04-01
To assess the extent and duration of the effect of tongue cleaning procedures on bacterial load on the dorsal surface of the tongue. 19 subjects participated in this blinded crossover study. Subjects abstained from oral hygiene, eating and drinking from 22:00 h the previous evening. Tongue samples were collected at baseline and within 15 minutes of one of three procedures: teeth brushing alone; teeth brushing plus tongue scraping; teeth brushing plus tongue cleaning using a high speed vacuum ejector and irrigation with 20 ml antibacterial mouthwash. Subjects then brushed twice daily for 3 days apart from the second group who additionally scraped their tongue twice daily. On day 4, baseline and post-treatment samples were collected as per day 1. Bacteria (total anaerobes, Gram-negative anaerobes, VSC-producing bacteria and Streptococcus saliuarius) were enumerated using appropriate selective media. The tongue dorsum was colonized by all 4 bacterial categories (log(10) 6-8 cfu/sample). For subjects who brushed their teeth only, there was a significant reduction from baseline for S. saliuarius only. In contrast, tooth brushing plus tongue scraping resulted in statistically significant reductions from baseline for all bacterial categories (range log(10) 0.11-0.40 cfu/sample). Highly statistically significant reductions (log(10) 1.11-1.96 cfu/sample) were observed for subjects who underwent thorough tongue cleaning with the saliva ejector/mouthwash. To determine longevity of treatment effects, baseline bacterial loads for days 1 and 4 were compared. Only daily tongue scraping resulted in statistical significant reduction in baseline microbial loads on day 4. While mechanical tongue cleaning with or without chemical intervention can reduce bacterial load on the tongue, this effect is transient, and regular tongue cleaning is required to provide a long lasting (overnight) reduction in bacterial numbers. Nevertheless, tongue cleaning is an oral hygiene procedure that is little practiced due to discomfort and/or lack of awareness on the part of dental professionals and their patients.
-
Strauss, André; Dobrowsky, Penelope Heather; Ndlovu, Thando; Reyneke, Brandon; Khan, Wesaal
2016-12-09
Numerous pathogens and opportunistic pathogens have been detected in harvested rainwater. Developing countries, in particular, require time- and cost-effective treatment strategies to improve the quality of this water source. The primary aim of the current study was thus to compare solar pasteurization (SOPAS; 70 to 79 °C; 80 to 89 °C; and ≥90 °C) to solar disinfection (SODIS; 6 and 8 hrs) for their efficiency in reducing the level of microbial contamination in harvested rainwater. The chemical quality (anions and cations) of the SOPAS and SODIS treated and untreated rainwater samples were also monitored. While the anion concentrations in all the samples were within drinking water guidelines, the concentrations of lead (Pb) and nickel (Ni) exceeded the guidelines in all the SOPAS samples. Additionally, the iron (Fe) concentrations in both the SODIS 6 and 8 hr samples were above the drinking water guidelines. A >99% reduction in Escherichia coli and heterotrophic bacteria counts was then obtained in the SOPAS and SODIS samples. Ethidium monoazide bromide quantitative polymerase chain reaction (EMA-qPCR) analysis revealed a 94.70% reduction in viable Legionella copy numbers in the SOPAS samples, while SODIS after 6 and 8 hrs yielded a 50.60% and 75.22% decrease, respectively. Similarly, a 99.61% reduction in viable Pseudomonas copy numbers was observed after SOPAS treatment, while SODIS after 6 and 8 hrs yielded a 47.27% and 58.31% decrease, respectively. While both the SOPAS and SODIS systems reduced the indicator counts to below the detection limit, EMA-qPCR analysis indicated that SOPAS treatment yielded a 2- and 3-log reduction in viable Legionella and Pseudomonas copy numbers, respectively. Additionally, SODIS after 8 hrs yielded a 2-log and 1-log reduction in Legionella and Pseudomonas copy numbers, respectively and could be considered as an alternative, cost-effective treatment method for harvested rainwater.
-
A comparison of the survival of F+RNA and F+DNA coliphages in lake water microcosms.
Long, Sharon C; Sobsey, Mark D
2004-03-01
The survival of seven F+RNA phages (MS2 Group I ATCC type strain, two Group I environmental isolates, a Group II environmental isolate, a Group III environmental isolate, and two Group IV environmental isolates) and six F+DNA phages (M13, fd, f1, and ZJ/2 ATCC type strains, and two environmental isolates) were examined in microcosms using a surface drinking water source. Phages were spiked into replicate aliquots of a source water at about 20,000 pfu/ml. Replicate spikes were incubated at 4 and 20 degrees C and monitored for 110 days. At 4 degrees C, Groups I and II F+ RNA phages were detectable through 110 days, with reductions of about 1 and 3 log10, respectively. The Group III F+RNA phage demonstrated 5 log10 reduction after 3 weeks, and the Group IV F+RNA phages were reduced to detection limits (5 log10 reduction) within 10 days. Of the F+DNA phages, all four type strains were detectable with about 2.5 log10 reduction after 110 days at 4 degrees C. The F+DNA environmental isolates were detectable with about a 4 log10 reduction after 110 days at 4 degrees C. All phages demonstrated faster decay at 20 degrees C. These results suggest that differences in F+ phage survival may influence their prevalence in environmental waters and the ability to attribute their prevalence to specific human and animal sources of faecal contamination.
-
Gallandat, Karin; Daniels, Kyle; Desmarais, Anne Marie; Scheinman, Pamela; Lantagne, Daniele
2017-01-01
To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94–3.01 log reduction in E. coli concentration without, and 2.18–3.34 with, soil load; and a 2.44–3.06 log reduction in Phi6 without, and 2.71–3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28–4.77 log reduction in remaining E. coli without, and 0.21–4.49 with, soil load and a 1.26–2.02 log reduction in Phi6 without, and 1.30–2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001). Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence. PMID:28231311
-
Effect of copper and silver ionization on Legionella pneumophila eradication
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lin, Y.E.; Vidic, R.D.; Stout, J.E.
1995-11-01
The presence of Legionella pneumophila in water distribution systems has been epidemiologically linked to hospital-acquired Legionnaires` disease. The objective of this study was to evaluate the efficiency of copper and silver ions for inactivation of Legionella pneumophila. Experimental results showed that L. pneumophila was completely inactivated at copper concentration of 0.1 mg/L within the period of 2.5 hours while 6-log reduction requires a Ct value of 0.8 mg/L*hour. On the other hand, more than 24 hours was required to completely eradicate L. pneumophila at the highest silver ion concentration (0.08 mg/L) tested and only 4-log reduction is observed for Ctmore » value of 0.8 mg/L*hour. The effective synergism of these ions in eradicating L. pneumophila was observed for copper concentrations of 0.05 and silver concentration of 0.04 mg/L. One approach for the control of L. pneumophila in water distribution systems is to initiate copper/silver ion concentrations at 0.4/0.04 mg/L to achieve complete eradication of L. pneumophila already present in the water distribution system (as established in previous studies) followed by a lower residual (0.05/0.04 mg/L) protection against L. pneumophila in the incoming water.« less
-
Risk-Based Treatment Targets for Onsite Non-Potable Water ...
This presentation presents risk-based enteric pathogen log reduction targets for non-potable and potable uses of a variety of alternative source waters (i.e., municipal wastewater, locally-collected greywater, rainwater, and stormwater). A probabilistic, forward Quantitative Microbial Risk Assessment (QMRA) was used to derive the pathogen log10 reduction targets (LRTs) that corresponded with an infection risk of either 10-4 per person per year (ppy) or 10-2 ppy. The QMRA accounted for variation in pathogen concentration and sporadic pathogen occurrence (when data were available) in source waters for reference pathogens Rotavirus, Adenovirus, Norovirus, Campylobacter spp., Salmonella spp., Giardia spp., and Cryptosporidium spp.. Non-potable uses included indoor use (for toilet flushing and clothes washing) with accidental ingestion of treated non-potable water (or cross connection with potable water), and unrestricted irrigation for outdoor use. Various exposure scenarios captured the uncertainty from key inputs, i.e., the pathogen concentration in source water; the volume of water ingested; and for the indoor use, the frequency of and the fraction of the population exposed to accidental ingestion. Both potable and non-potable uses required pathogen treatment for the selected waters and the LRT was generally greater for potable use than nonpotable indoor use and unrestricted irrigation. The difference in treatment requirements among source waters was driven by th
-
Gayán, E; Torres, J A; Alvarez, I; Condón, S
2014-02-01
The effect of bactericidal UV-C treatments (254 nm) on Escherichia coli O157:H7 suspended in apple juice increased synergistically with temperature up to a threshold value. The optimum UV-C treatment temperature was 55 °C, yielding a 58.9% synergistic lethal effect. Under these treatment conditions, the UV-heat (UV-H55 °C) lethal variability achieving 5-log reductions had a logistic distribution (α = 37.92, β = 1.10). Using this distribution, UV-H55 °C doses to achieve the required juice safety goal with 95, 99, and 99.9% confidence were 41.17, 42.97, and 46.00 J/ml, respectively, i.e., doses higher than the 37.58 J/ml estimated by a deterministic procedure. The public health impact of these results is that the larger UV-H55 °C dose required for achieving 5-log reductions with 95, 99, and 99.9% confidence would reduce the probability of hemolytic uremic syndrome in children by 76.3, 88.6, and 96.9%, respectively. This study illustrates the importance of including the effect of data variability when selecting operational parameters for novel and conventional preservation processes to achieve high food safety standards with the desired confidence level.
-
Rambags, Femke; Tanner, Chris C; Stott, Rebecca; Schipper, Louis A
2016-05-01
Denitrifying bioreactors using woodchips or other slow-release carbon sources can be an effective method for removing nitrate (NO) from wastewater and tile drainage. However, the ability of these systems to remove fecal microbes from wastewater has been largely uninvestigated. In this study, reductions in fecal indicator bacteria () and viruses (F-specific RNA bacteriophage [FRNA phage]) were analyzed by monthly sampling along a longitudinal transect within a full-scale denitrifying woodchip bioreactor receiving secondary-treated septic tank effluent. Nitrogen, phosphorus, 5-d carbonaceous biochemical oxygen demand (CBOD), and total suspended solids (TSS) reduction were also assessed. The bioreactor demonstrated consistent and substantial reduction of (2.9 log reduction) and FRNA phage (3.9 log reduction) despite receiving highly fluctuating inflow concentrations [up to 3.5 × 10 MPN (100 mL) and 1.1 × 10 plaque-forming units (100 mL) , respectively]. Most of the removal of fecal microbial contaminants occurred within the first meter of the system (1.4 log reduction for ; 1.8 log reduction for FRNA phage). The system was also efficient at removing NO (>99.9% reduction) and TSS (89% reduction). There was no evidence of consistent removal of ammonium, organic nitrogen, or phosphorus. Leaching of CBOD occurred during initial operation but decreased and stabilized at lower values (14 g O m) after 9 mo. We present strong evidence for reliable microbial contaminant removal in denitrifying bioreactors, demonstrating their broader versatility for wastewater treatment. Research on the removal mechanisms of microbial contaminants in these systems, together with the assessment of longevity of removal, is warranted. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.
-
Inactivation of Salmonella Enteritidis on lettuces used by minimally processed vegetable industries.
Silveira, Josete Bailardi; Hessel, Claudia Titze; Tondo, Eduardo Cesar
2017-01-30
Washing and disinfection methods used by minimally processed vegetable industries of Southern Brazil were reproduced in laboratory in order to verify their effectiveness to reduce Salmonella Enteritidis SE86 (SE86) on lettuce. Among the five industries investigated, four carried out washing with potable water followed by disinfection with 200 ppm sodium hypochlorite during different immersion times. The washing procedure alone decreased approximately 1 log CFU/g of SE86 population and immersion times of 1, 2, 5, and 15 minutes in disinfectant solution demonstrated reduction rates ranging from 2.06±0.10 log CFU/g to 3.01±0.21 log CFU/g. Rinsing alone was able to reduce counts from 0.12±0.63 log CFU/g to 1.90±1.07 log CFU/g. The most effective method was washing followed by disinfection with 200 ppm sodium hypochlorite for 15 minutes and final rinse with potable water, reaching 5.83 log CFU/g of reduction. However, no statistical differences were observed on the reduction rates after different immersion times. A time interval of 1 to 2 minutes may be an advantage to the minimally vegetable processed industries in order to optimize the process without putting at risk food safety.
-
Low-Temperature Decontamination with Hydrogen Peroxide or Chlorine Dioxide for Space Applications
Macken, S.; Giri, K.; Walker, J. T.; Bennett, A. M.
2012-01-01
The currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction at temperatures of >110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effective and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative to dry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseous decontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m3 exposure chamber. Five spore-forming Bacillus spp. were exposed on stainless steel coupons to vaporized hydrogen peroxide and chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery of Bacillus atrophaeus and Geobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required an exposure period of 60 min to reduce both B. atrophaeus and G. stearothermophilus by 5 logs. Of the three other Bacillus spp. tested, Bacillus thuringiensis proved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and 6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing the Bacillus spp. tested within the exposure ranges by over 5 logs, with the exception of B. thuringiensis, which was more resistant to both technologies. These results indicate that a review of the indicator organism choice and loading could provide a more appropriate and realistic challenge for the sterilization procedures used in the space industry. PMID:22492450
-
Alternative Fuels Data Center: Petroleum and Emission Reduction Planning
Add Goal à Log In You need an account to save your plans. If you already have an account, log in below. Otherwise, create an account. Email address: Password: Confirm password: LOG IN Cancel Forgot
-
Jensen, Dane A; Danyluk, Michelle D; Harris, Linda J; Schaffner, Donald W
2015-04-01
Hand washing is recognized as a crucial step in preventing foodborne disease transmission by mitigating crosscontamination among hands, surfaces, and foods. This research was undertaken to establish the importance of several keys factors (soap, soil, time, and drying method) in reducing microorganisms during hand washing. A nonpathogenic nalidixic acid-resistant Enterobacter aerogenes surrogate for Salmonella was used to assess the efficacy of using soap or no soap for 5 or 20 s on hands with or without ground beef debris and drying with paper towel or air. Each experiment consisted of 20 replicates, each from a different individual with ∼ 6 log CFU/ml E. aerogenes on their hands. A reduction of 1.0 ± 0.4 and 1.7 ± 0.8 log CFU of E. aerogenes was observed for a 5-s wash with no soap and a 20-s wash with soap, respectively. When there was no debris on the hands, there was no significant difference between washing with and without soap for 20 s (P > 0.05). Likewise, there was no significant difference in the reductions achieved when washing without soap, whether or not debris was on the hands (P > 0.05). A significantly greater reduction (P < 0.05) in E. aerogenes (0.5 log CFU greater reduction) was observed with soap when there was ground beef debris on the hands. The greatest difference (1.1 log CFU greater average reduction) in effectiveness occurred when ground beef debris was on the hands and a 20-s wash with water was compared with a 20-s wash with soap. Significantly greater (P < 0.05) reductions were observed with paper towel drying compared with air (0.5 log CFU greater reductions). Used paper towels may contain high bacterial levels (>4.0 log CFU per towel) when hands are highly contaminated. Our results support future quantitative microbial risk assessments needed to effectively manage risks of foodborne illness in which food workers' hands are a primary cause.
-
Inactivation of Bacillus spores by the supercritical carbon dioxide micro-bubble method.
Ishikawa, H; Shimoda, M; Tamaya, K; Yonekura, A; Kawano, T; Osajima, Y
1997-06-01
Bacillus spores were effectively inactivated by the supercritical (SC) CO2 micro-bubble method. The micro-bubble SC CO2 treatment of B. cereus, B. subtilis, B. megaterium, B. polymyxa, and B. coagulans at 40 degrees C and 30 MPa for 30 min produced greater reduction (about 3 log cycles of reduction) than a similar treatment without a filter. The SC CO2 treatment of B. polymyxa, B. cereus, and B. subtilis spores at 45 degrees C, 50 degrees C, respectively, and 30 MPa for 60 min resulted in a 6-log cycle reduction of survival. The SC CO2 treatment under the foregoing conditions should offer higher efficiency than that of heat treatment at 100 degrees C for 60 min. In addition, the SC CO2 treatment (30 MPa, 60 degrees C, 30 min) of B. polymyxa and B. cereus spores also produced a 6-log cycle reduction.
-
Wolfand, Jordyn M; Bell, Colin D; Boehm, Alexandria B; Hogue, Terri S; Luthy, Richard G
2018-06-05
Stormwater best management practices (BMPs) are implemented to reduce microbial pollution in runoff, but their removal efficiencies differ. Enhanced BMPs, such as those with media amendments, can increase removal of fecal indicator bacteria (FIB) in runoff from 0.25-log 10 to above 3-log 10 ; however, their implications for watershed-scale management are poorly understood. In this work, a computational model was developed to simulate watershed-scale bacteria loading and BMP performance using the Ballona Creek Watershed (Los Angeles County, CA) as a case study. Over 1400 scenarios with varying BMP performance, percent watershed area treated, BMP treatment volume, and infiltrative capabilities were simulated. Incremental improvement of BMP performance by 0.25-log 10 , while keeping other scenario variables constant, reduces annual bacterial load at the outlet by a range of 0-29%. In addition, various simulated scenarios provide the same FIB load reduction; for example, 75% load reduction is achieved by diverting runoff from either 95% of the watershed area to 25 000 infiltrating BMPs with 0.5-log 10 removal or 75% of the watershed area to 75 000 infiltrating BMPs with 1.5-log 10 removal. Lastly, simulated infiltrating BMPs provide greater FIB reduction than noninfiltrating BMPs at the watershed scale. Results provide new insight on the trade-offs between BMP treatment volume, performance, and distribution.
-
Mafart, P; Leguérinel, I; Couvert, O; Coroller, L
2010-08-01
The assessment and optimization of food heating processes require knowledge of the thermal resistance of target spores. Although the concept of spore resistance may seem simple, the establishment of a reliable quantification system for characterizing the heat resistance of spores has proven far more complex than imagined by early researchers. This paper points out the main difficulties encountered by reviewing the historical works on the subject. During an early period, the concept of individual spore resistance had not yet been considered and the resistance of a strain of spore-forming bacterium was related to a global population regarded as alive or dead. A second period was opened by the introduction of the well-known D parameter (decimal reduction time) associated with the previously introduced z-concept. The present period has introduced three new sources of complexity: consideration of non log-linear survival curves, consideration of environmental factors other than temperature, and awareness of the variability of resistance parameters. The occurrence of non log-linear survival curves makes spore resistance dependent on heating time. Consequently, spore resistance characterisation requires at least two parameters. While early resistance models took only heating temperature into account, new models consider other environmental factors such as pH and water activity ("horizontal extension"). Similarly the new generation of models also considers certain environmental factors of the recovery medium for quantifying "apparent heat resistance" ("vertical extension"). Because the conventional F-value is no longer additive in cases of non log-linear survival curves, the decimal reduction ratio should be preferred for assessing the efficiency of a heating process. Copyright 2010 Elsevier Ltd. All rights reserved.
-
Mukhopadhyay, Sudarsan; Sokorai, Kimberly; Ukuku, Dike; Fan, Xuetong; Juneja, Vijay; Sites, Joseph; Cassidy, Jennifer
2016-10-17
The objective of this research was to evaluate and develop a method for inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree (CP) by high hydrostatic pressure (HHP). Cantaloupe being the most netted varieties of melons presents a greater risk of pathogen transmission. Freshly prepared CP with or without 0.1% ascorbic acid (AA) was inoculated with a bacterial cocktail composed of a three serotype mixture of S. enterica (S. Poona, S. Newport H1275 and S. Stanley H0558) and a mixture of three strains of L. monocytogenes (Scott A, 43256 and 51742) to a population of ca. 10(8)CFU/g. Double sealed and double bagged inoculated CP (ca. 5g) were pressure treated at 300, 400 and 500MPa at 8°C and 15°C for 5min. Data indicated increased inactivation of both Salmonella and Listeria spp. with higher pressure. Log reduction for CP at 300MPa, 8°C for 5min was 2.4±0.2 and 1.6±0.5logCFU/g for Salmonella and Listeria, respectively. Survivability of the pathogens was significantly compromised at 400MPa and 8°C, inactivating 4.5±0.3logCFU/g of Salmonella and 3.0±0.4logCFU/g of Listeria spp. Complete inactivation of the pathogens in the puree (log reduction >6.7logCFU/g), with or without AA, was achieved when the pressure was further increased to 500MPa, except that for Listeria containing no AA at 8°C. Listeria presented higher resistance to pressure treatment compared to Salmonella spp. Initial temperatures (8 and 15°C) had no significant influence on Salmonella log reductions. Log reduction of pathogens increased but not significantly with increase of temperature. AA did not show any significant antimicrobial activity. Viable counts were about 0.2-0.4logCFU/g less in presence of 0.1% AA. These data validate that HHP can be used as an effective method for decontamination of cantaloupe puree. Published by Elsevier B.V.
-
Log sort yard economics, planning, and feasibility
John Rusty Dramm; Robert Govett; Ted Bilek; Gerry L. Jackson
2004-01-01
This publication discusses basic marketing and economic concepts, planning approach, and feasibility methodology for assessing log sort yard operations. Special attention is given to sorting small diameter and underutilized logs from forest restoration, fuels reduction, and thinning operations. A planned programming approach of objectively determining the feasibility...
-
Paik, Hyun-Dong; Lee, Joo-Yeon
2014-08-01
Lactobacillus brevis KGR3111, Lactobacillus curvatus KGR 2103, Lactobacillus plantarum KGR 5105, and Lactobacillus sakei KGR 4108 isolated from kimchi were investigated for their potential to be used as starter culture for fermented sausages with the capability to reduce and tolerate nitrate/nitrite. The reduction capability of tested strains for nitrate was not dramatic. All tested strains, however, showed the capability to produce nitrite reductase with the reduction amount of 58.46-75.80 mg/l of NO(2)(-). L. brevis and L. plantarum showed nitrate tolerance with the highest number of 8.71 log cfu/ml and 8.81 log cfu/ml, and L. brevis and L. sakei exhibited nitrite tolerance with the highest number of 8.24 log cfu/ml and 8.25 log cfu/ml, respectively. As a result, L. brevis, L. plantarum, and L. sakei isolated from kimchi showed a tolerance against nitrate or nitrite with a good nitrite reduction capability, indicating the satisfaction of one of the selection criteria to be used as starter culture for fermented sausages. Copyright © 2014 Elsevier Ltd. All rights reserved.
-
Financial feasibility of a log sort yard handling small-diameter logs: A preliminary study
Han-Sup Han; E. M. (Ted) Bilek; John (Rusty) Dramm; Dan Loeffler; Dave Calkin
2011-01-01
The value and use of the trees removed in fuel reduction thinning and restoration treatments could be enhanced if the wood were effectively evaluated and sorted for quality and highest value before delivery to the next manufacturing destination. This article summarizes a preliminary financial feasibility analysis of a log sort yard that would serve as a log market to...
-
Ruhong Li; J. Buongiorno; J.A. Turner; S. Zhu; J. Prestemon
2008-01-01
We assessed the impact on the world forest sector of a progressive elimination of illegal logging. The analysis compared predictions from 2007 to 2020, with and without a gradual reduction of illegally logged industrial roundwood from 2007 to 2011. A large part of the curtailment of timber supply due to the stoppage of illegal logging would be compensated by increased...
-
Castillo, A; Lucia, L M; Goodson, K J; Savell, J W; Acuff, G R
1998-07-01
Cleaning treatments, such as high-pressure water wash at 35 degrees C or trim, alone and combined with sanitizing treatments, such as hot water (95 degrees C at the source), warm (55 degrees C) 2% lactic acid spray, and combinations of these two sanitizing methods, were compared for their effectiveness in reducing inoculated numbers (5.0 to 6.0 log CFU/cm2) of Salmonella typhimurium, Escherichia coli O157:H7, aerobic plate counts, Enterobacteriaceae, total coliforms, thermotolerant coliforms, and generic E. coli on hot beef carcass surface areas in a model carcass spray cabinet. Log reductions in numbers of all tested organisms by water wash or trim alone were significantly smaller than the log reductions obtained by the different combined treatments. Regardless of the cleaning treatment (water wash or trim) or surface area, the range for mean log reductions by hot water was from 4.0 to > 4.8 log CFU/cm2, by lactic acid spray was from 4.6 to > 4.9 log CFU/cm2, by hot water followed by lactic acid spray was from 4.5 to > 4.9 log CFU/cm2, and by lactic acid spray followed by hot water was from 4.4 to > 4.6 log CFU/cm2, for S. typhimurium and E. coli O157:H7. Identical reductions were obtained for thermotolerant coliforms and generic E. coli. No differences in bacterial reductions were observed for different carcass surface regions. Water wash and trim treatments caused spreading of the contamination to other areas of the carcass surface while providing an overall reduction in fecal or pathogenic contamination on carcass surface areas. This relocated contamination after either water wash or trim was most effectively reduced by following with hot water and then lactic acid spray. This combined treatment yielded 0% positive samples for S. typhimurium, E. coli O157:H7, thermotolerant coliforms, and generic E. coli on areas outside the inoculated areas, whereas percent positive samples after applying other combined treatments ranged from 22 to 44% for S. typhimurium, 0 to 44% for E. coli O157:H7, and 11 to 33% for both thermotolerant coliforms and generic E. coli. From data collected in this study, it is possible to choose an effective, inexpensive treatment to reduce bacterial contamination on beef carcasses. In addition, the similar reduction rates of total coliforms, thermotolerant coliforms, or generic E. coli may be useful in identifying an indicator to verify the effectiveness of the selected treatment as a critical control point in a Hazard Analysis and Critical Control Point program.
-
Rajkowski, Kathleen T; Ashurst, Kean
2009-11-01
To achieve the production of pathogen-free sprouts, there must be appropriate mixing of liquid sanitizer with the seeds to assure contact. Commercial treatments by irradiation or ozone gas of Salmonella spp. artificially inoculated seeds were compared, and these resulted in a 1 log reduction after all treatments. Use of peroxyacetic acid (1%) sanitizer on Salmonella spp. or Escherichia coli O157:H7 inoculated alfalfa seeds consistently resulted in a greater than 1 log reduction. In addition, during these studies debris was noted after the seeds were removed. Based on this observation, an air-mixing wash basin was developed for commercial use. Validation was done by commercial growers using 1% peroxyacetic acid sanitizer to wash seeds in the air-mixing basin, followed by sprouting the seeds. No positive or false-positive pathogen results were reported after the required testing of the sprout water (run-off during sprouting). Use of 1% peroxyacetic acid sanitizer in the air-mixing wash basin does provide the sprout grower an effective means of sanitizing sprout seeds.
-
Application of ozonated dry ice (ALIGAL™ Blue Ice) for packaging and transport in the food industry.
Fratamico, Pina M; Juneja, Vijay; Annous, Bassam A; Rasanayagam, Vasuhi; Sundar, M; Braithwaite, David; Fisher, Steven
2012-05-01
Dry ice is used by meat and poultry processors for temperature reduction during processing and for temperature maintenance during transportation. ALIGAL™ Blue Ice (ABI), which combines the antimicrobial effect of ozone (O(3)) along with the high cooling capacity of dry ice, was investigated for its effect on bacterial reduction in air, in liquid, and on food and glass surfaces. Through proprietary means, O(3) was introduced to produce dry ice pellets to a concentration of 20 parts per million (ppm) by total weight. The ABI sublimation rate was similar to that of dry ice pellets under identical conditions, and ABI was able to hold the O(3) concentration throughout the normal shelf life of the product. Challenge studies were performed using different microorganisms, including E. coli, Campylobacter jejuni, Salmonella, and Listeria, that are critical to food safety. ABI showed significant (P < 0.05) microbial reduction during bioaerosol contamination (up to 5-log reduction of E. coli and Listeria), on chicken breast (approximately 1.3-log reduction of C. jejuni), on contact surfaces (approximately 3.9 log reduction of C. jejuni), and in liquid (2-log reduction of C. jejuni). Considering the stability of O(3), ease of use, and antimicrobial efficacy against foodborne pathogens, our results suggest that ABI is a better alternative, especially for meat and poultry processors, as compared to dry ice. Further, ABI can potentially serve as an additional processing hurdle to guard against pathogens during processing, transportation, distribution, and/or storage. © 2012 Institute of Food Technologists®
-
Poimenidou, Sofia V; Bikouli, Vasiliki C; Gardeli, Chryssavgi; Mitsi, Christina; Tarantilis, Petros A; Nychas, George-John; Skandamis, Panagiotis N
2016-03-02
Aqueous extract of Origanum vulgare (oregano), sodium hypochlorite (60 and 300 ppm of free chlorine), Citrox® (containing citric acid and phenolic compounds [bioflavonoids] as active ingredients), vinegar, lactic acid, and double combinations of Citrox, lactic acid and oregano were evaluated against Escherichia coli O157:H7 and total mesophilic microbiota on fresh-cut spinach and lettuce and for their impact on color of treated vegetables. Spinach and lettuce leaves were inoculated with E. coli O157:H7 to a level of 5-6 log CFU/g and immersed in washing solutions for 2 or 5 min at 20 °C, followed by rinsing with ice water (30s). Bacterial populations on vegetables were enumerated immediately after washing and after storage of the samples at 5 °C for 7 days under 20% CO2: 80% N2. No significant post-washing microbial reductions were achieved by chlorinated water, whereas after storage total microbiota was increased by 2.4 log CFU/g on lettuce. Vinegar wash was the most effective treatment causing E. coli O157:H7 reductions of 1.8-4.3 log CFU/g. During storage, pathogen was further decreased to below the detection limit level (<2 log CFU/g) and total microbiota exhibited the highest reductions compared to other treatments. Lactic acid reduced pathogen by 1.6-3.7 log CFU/g after washing; however levels of total microbiota increased by up to 2 log CFU/g on packaged lettuce during storage. Washing lettuce samples with oregano for 2 min resulted in 2.1 log CFU/g reduction of E. coli O157:H7. When Citrox was combined with oregano, 3.7-4.0 log CFU/g reduction was achieved on spinach and lettuce samples, with no significant effect on color parameters. Additionally, rinsing with ice water after decontamination treatments contributed to maintenance of color of the treated vegetables. In conclusion, the results indicated that vinegar, lactic acid or oregano aqueous extract alone or in combination, as alternative washing solutions to chlorine, may be effectively used to control E. coli O157:H7 and sustain acceptable appearance of fresh cut spinach and lettuce. Copyright © 2016 Elsevier B.V. All rights reserved.
-
Effect of irradiation on stored vacuum packaged Wiltshire bacon
NASA Astrophysics Data System (ADS)
Dempster, JF; Halls, NA
Wiltshire cured 'middle-cut' bacon (NaCl, 4.87%; 40 mg/kg NO 2; 53 mg/kg NO 3) was boned, sliced and vacuum packaged. It was irradiated (25 kGy: 10 kGy) and stored aerobically (5 0 : 15 0). At weekly intervals the bacon was evaluated bacteriologically and organoleptically (appearance, odour, colour of lean and fat) against unirradiated (control) samples). Results indicated that irradiation (10 kGy) did not permanently inhibit bacterial growth. After initial reductions in count of 0.99 g -1-1(15 0C) and log 3.61 g -1 (5 0C), maximum numbers were reached in 28 days at 15 0C (log 10.32 g -1) and in 35 days at 5 0C (log 8.05 g -1). However viability was significantly affected by 25 kGy irradiation: final numbers reached being log 2.22 g -1 (15 0C) at 35 days and log 3.38 g -1 (5 0C) at 42 days. Appearance and colour (fat and lean) were not significantly impaired by irradiation. However the interaction of storage temperature (5 0 : 15 0C), irradiation (10 kGy: 25 kGy): duration of storage (42 days) and initial count (log 7.24 g -1) had pronounced adverse effects on odour judgements. Evaluation of odour changes in bacon due to irradiation require further investigation. This is especially so since it is often possible to detect odour changes in raw meat after doses as low as 0.5 kGy (Coleby 1959).
-
Dunkin, Nathan; Weng, ShihChi; Coulter, Caroline G; Jacangelo, Joseph G; Schwab, Kellogg J
2017-10-17
The objective of this study was to characterize human norovirus (hNoV) GI and GII reductions during disinfection by peracetic acid (PAA) and monochloramine in secondary wastewater (WW) and phosphate buffer (PB) as assessed by reverse transcription-qPCR (RT-qPCR). Infectivity and RT-qPCR reductions are also presented for surrogate viruses murine norovirus (MNV) and bacteriophage MS2 under identical experimental conditions to aid in interpretation of hNoV molecular data. In WW, RT-qPCR reductions were less than 0.5 log 10 for all viruses at concentration-time (CT) values up to 450 mg-min/L except for hNoV GI, where 1 log 10 reduction was observed at CT values of less than 50 mg-min/L for monochloramine and 200 mg-min/L for PAA. In PB, hNoV GI and MNV exhibited comparable resistance to PAA and monochloramine with CT values for 2 log 10 RT-qPCR reduction between 300 and 360 mg-min/L. Less than 1 log 10 reduction was observed for MS2 and hNoV GII in PB at CT values for both disinfectants up to 450 mg-min/L. Our results indicate that hNoVs exhibit genogroup dependent resistance and that disinfection practices targeting hNoV GII will result in equivalent or greater reductions for hNoV GI. These data provide valuable comparisons between hNoV and surrogate molecular signals that can begin the process of informing regulators and engineers on WW treatment plant design and operational practices necessary to inactivate hNoVs.
-
TENSOR DECOMPOSITIONS AND SPARSE LOG-LINEAR MODELS
Johndrow, James E.; Bhattacharya, Anirban; Dunson, David B.
2017-01-01
Contingency table analysis routinely relies on log-linear models, with latent structure analysis providing a common alternative. Latent structure models lead to a reduced rank tensor factorization of the probability mass function for multivariate categorical data, while log-linear models achieve dimensionality reduction through sparsity. Little is known about the relationship between these notions of dimensionality reduction in the two paradigms. We derive several results relating the support of a log-linear model to nonnegative ranks of the associated probability tensor. Motivated by these findings, we propose a new collapsed Tucker class of tensor decompositions, which bridge existing PARAFAC and Tucker decompositions, providing a more flexible framework for parsimoniously characterizing multivariate categorical data. Taking a Bayesian approach to inference, we illustrate empirical advantages of the new decompositions. PMID:29332971
-
Inatsu, Yasuhiro; Ohata, Yukiko; Ananchaipattana, Chiraporn; Latiful Bari, Md; Hosotani, Yukie; Kawasaki, Susumu
2016-01-01
Fate of Escherichia coli O157 cells was evaluated when inoculated into each step after production of lightly pickled Chinese cabbage. The efficacy of surface sterilization by 100 mg/L of chlorine water for 10 min on raw leaves (6.0 log CFU/g) was 2.2 log CFU/g reduction. No meaningful change of the population of E. coli O157 (3.5 log CFU/g to 1.5 log MPN/g) contaminated into 19 kinds of products was observed. These results indicated the difficulty of estimating the viable count of the cells between contaminated on farms and further processing and storage steps. The population of E. coli O157 (3 log CFU/g to 1 log MPN/g) inoculated into the Chinese cabbage products was reduced less than 0.6 log CFU/g after 2 h-incubation at 37℃ in artificial gastric juice. Prevention from initial contamination of E. coli O157 on the ingredients of Chinese cabbage products is important to reduce the risk of food poisoning because the reduction of the bacterial counts after processing and consumption are limited.
-
Evaluation of Protamine as a Disinfectant for Contact Lenses.
Bandara, Mahesh K; Masoudi, Simin; Zhu, Hua; Bandara, Rani; Willcox, Mark D P
2016-11-01
To investigate the ability of protamine, alone or in combination with other antimicrobial agents, to kill bacteria and fungi associated with contact lens-related keratitis. The International Organization for Standardization 14729:2001 procedure was used to test the antimicrobial activity of solutions of protamine (23-228 μM) with and without polyhexamethylene biguanide (PHMB) and ethylenediamine tetra-acetic acid (EDTA). The recommended ISO panel of microbes along with six clinical isolates was tested. The effect of increasing sodium chloride concentration on the antimicrobial activity was also assessed. The cytotoxicity of the final protamine/EDTA/PHMB solution was measured using ISO 10993-5 standard assays. Protamine gave a dose-dependent antimicrobial effect, with the highest effect for most strains being at 228 μM (≥6 log reductions of viable bacteria and ≥1 log reduction of viable fungi). Addition of EDTA and PHMB increased the antimicrobial effect for all strains except Pseudomonas aeruginosa ATCC6538, which had optimum activity (≥6 log inhibition) even in protamine alone. The optimum antimicrobial activity of all microbes was achieved in 0.2% sodium chloride, but even in 0.8% sodium chloride, the activity met or exceeded the ISO standard (>3 log reductions for bacteria and >1 log reduction for fungi). None of the formulations was cytotoxic to mammalian cells. This study highlights the potential for protamine to be used for the development of effective multipurpose disinfection solutions. Further investigations such as stability, compatibility with contact lenses, and in vivo toxicity are warranted.
-
An evaluation of selected methods for the decontamination of cattle hides prior to skinning.
Small, A; Wells-Burr, B; Buncic, S
2005-02-01
The effectiveness of different decontamination treatments in reducing microbial loads on cattle hides was assessed. The 10-s hide treatments were conducted using a wet-and-dry vacuum cleaner filled with one of the liquids (heated to 50 °C) indicated below, followed or not by 10-min drying in the air. Also, the hide was clipped, followed or not by 10-s singeing using a hand-held blowtorch. Before and after each decontamination treatment, the hide was sampled (100 cm(2) areas) by a sponge-swabbing method to compare the total viable counts of bacteria (TVC). The largest bacterial reduction (P<0.001; 2.31log(10) cfu/cm(2)) was achieved by singeing of previously clipped hide. Treatment of hide with a food industry sanitizer solution (10% Betane Plus) resulted in significant reductions of 1.80 (P<0.001) and 1.98log(10) cfu/cm(2) (P<0.001) without and with subsequent drying, respectively. Treatment of hide with a food industry disinfectant (P3-Topactive DES) significantly reduced TVC by 0.97 (P<0.001) and 1.18log(10) cfu/cm(2) (P<0.001) without and with subsequent drying, respectively. Treatments of hide with water alone or with a food-safe detergent solution (Formula 963B), or hide clipping alone, did not produce significant decontamination effects. Since hide contamination is associated with microbial contamination of the carcasses, the results indicate that post-killing/pre-skinning hide decontamination (used alone, or in combination with carcass decontamination) has a potential to improve microbial meat safety. Nevertheless, further research is required to optimise the efficacy of these treatments in the reduction of specific pathogens under commercial conditions.
-
Postfire logging: is it beneficial to a forest?
Sally Duncan
2002-01-01
Public debate on postfire logging has intensified in recent years, particularly since passage of the "salvage rider" in 1995, directing accelerated harvest of dead trees in the western United States. Supporters of postfires logging argue that it is part of a suite of restoration techniques, and that removal of timber means reduction of fuels for...
-
Nyiro, Joyce Uchi; Sande, Charles Jumba; Mutunga, Martin; Kiyuka, Patience Kerubo; Munywoki, Patrick Kioo; Scott, John Anthony G; Nokes, David James
2016-01-01
The target group for severe respiratory syncytial virus (RSV) disease prevention is infants under 6 months of age. Vaccine boosting of antibody titres in pregnant mothers could protect these young infants from severe respiratory syncytial virus (RSV) associated disease. Quantifying protective levels of RSV-specific maternal antibody at birth would inform vaccine development. A case control study nested in a birth cohort (2002-07) was conducted in Kilifi, Kenya; where 30 hospitalised cases of RSV-associated severe disease were matched to 60 controls. Participants had a cord blood and 2 subsequent 3-monthly blood samples assayed for RSV-specific neutralising antibody by the plaque reduction neutralisation test (PRNT). Two sample paired t test and conditional logistic regression were used in analyses of log2PRNT titres. The mean RSV log2PRNT titre at birth for cases and controls were not significantly different (P = 0.4) and remained so on age-stratification. Cord blood PRNT titres showed considerable overlap between cases and controls. The odds of RSV disease decreased with increase in log2PRNT cord blood titre. There was a 30% reduction in RSV disease per unit increase in log2PRNT titre (<3months age group) but not significant (P = 0.3). From this study, there is no strong evidence of protection by maternal RSV specific antibodies from severe RSV disease. Cord antibody levels show wide variation with considerable overlap between cases and controls. It is likely that, there are additional factors to specific PRNT antibody levels which determine susceptibility to severe RSV disease. In addition, higher levels of neutralizing antibody beyond the normal range may be required for protection; which it is hoped can be achieved by a maternal RSV vaccine.
-
Tracking Human Adenovirus Inactivation by Gamma Radiation under Different Environmental Conditions
Pimenta, Andreia I.; Guerreiro, Duarte; Madureira, Joana; Margaça, Fernanda M. A.
2016-01-01
ABSTRACT Adenovirus is the most prevalent enteric virus in waters worldwide due to its environmental stability, which leads to public health concerns. Mitigation strategies are therefore required. The aim of this study was to assess the inactivation of human adenovirus type 5 (HAdV-5) by gamma radiation in aqueous environments. Various substrates with different organic loads, including domestic wastewater, were inoculated with HAdV-5 either individually or in a viral pool (with murine norovirus type 1 [MNV-1]) and were irradiated in a Cobalt-60 irradiator at several gamma radiation doses (0.9 to 10.8 kGy). The infectivity of viral particles, before and after irradiation, was tested by plaque assay using A549 cells. D10 values (dose required to inactivate 90% of a population or the dose of irradiation needed to produce a 1 log10 reduction in the population) were estimated for each substrate based on virus infectivity inactivation exponential kinetics. The capability of two detection methods, nested PCR and enzyme-linked immunosorbent assay (ELISA), to track inactivated viral particles was also assessed. After irradiation at 3.5 kGy, a reduction of the HAdV-5 titer of 4 log PFU/ml on substrates with lower organic loads was obtained, but in highly organic matrixes, the virus titer reduction was only 1 log PFU/ml. The D10 values of HAdV-5 in high organic substrates were significantly higher than in water suspensions. The obtained results point out some discrepancies between nested PCR, ELISA, and plaque assay on the assessments of HAdV-5 inactivation. These results suggest that the inactivation of HAdV-5 by gamma radiation, in aqueous environments, is significantly affected by substrate composition. This study highlights the virucidal potential of gamma radiation that may be used as a disinfection treatment for sustainable water supplies. IMPORTANCE Human adenovirus (HAdV) is the most prevalent of the enteric viruses in environmental waters worldwide. The purposes of this study are to provide new insights on the inactivation of enteric virus by gamma irradiation and to introduce new concepts and reinforce the benefits and utility of radiation technologies as disinfection processes. This may be an effective tool to guarantee the reduction of viral pathogens and to contribute to public health and sustainable water supplies. PMID:27316961
-
Berger, Philip; Messner, Michael J; Crosby, Jake; Vacs Renwick, Deborah; Heinrich, Austin
2018-05-01
Spore reduction can be used as a surrogate measure of Cryptosporidium natural filtration efficiency. Estimates of log10 (log) reduction were derived from spore measurements in paired surface and well water samples in Casper Wyoming and Kearney Nebraska. We found that these data were suitable for testing the hypothesis (H 0 ) that the average reduction at each site was 2 log or less, using a one-sided Student's t-test. After establishing data quality objectives for the test (expressed as tolerable Type I and Type II error rates), we evaluated the test's performance as a function of the (a) true log reduction, (b) number of paired samples assayed and (c) variance of observed log reductions. We found that 36 paired spore samples are sufficient to achieve the objectives over a wide range of variance, including the variances observed in the two data sets. We also explored the feasibility of using smaller numbers of paired spore samples to supplement bioparticle counts for screening purposes in alluvial aquifers, to differentiate wells with large volume surface water induced recharge from wells with negligible surface water induced recharge. With key assumptions, we propose a normal statistical test of the same hypothesis (H 0 ), but with different performance objectives. As few as six paired spore samples appear adequate as a screening metric to supplement bioparticle counts to differentiate wells in alluvial aquifers with large volume surface water induced recharge. For the case when all available information (including failure to reject H 0 based on the limited paired spore data) leads to the conclusion that wells have large surface water induced recharge, we recommend further evaluation using additional paired biweekly spore samples. Published by Elsevier GmbH.
-
Nasser, Abidelfatah M; Benisti, Neta-Lee; Ofer, Naomi; Hovers, Sivan; Nitzan, Yeshayahu
2017-01-28
Advanced wastewater treatment processes are applied to prevent the environmental dissemination of pathogenic microorganisms. Giardia lamblia causes a severe disease called giardiasis, and is highly prevalent in untreated wastewater worldwide. Monitoring the microbial quality of wastewater effluents is usually based on testing for the levels of indicator microorganisms in the effluents. This study was conducted to compare the suitability of fecal coliforms, F+ coliphages and sulfide reducing clostridia (SRC) as indicators for the reduction of Giardia cysts in two full-scale wastewater treatment plants. The treatment process consists of activated sludge, coagulation, high rate filtration and either chlorine or UV disinfection. The results of the study demonstrated that Giardia cysts are highly prevalent in raw wastewater at an average concentration of 3600 cysts/L. Fecal coliforms, F+ coliphages and SRC were also detected at high concentrations in raw wastewater. Giardia cysts were efficiently removed (3.6 log 10 ) by the treatment train. The greatest reduction was observed for fecal coliforms (9.6 log 10 ) whereas the least reduction was observed for F+ coliphages (2.1 log 10 ) following chlorine disinfection. Similar reduction was observed for SRC by filtration and disinfection by either UV (3.6 log 10 ) or chlorine (3.3 log 10 ). Since F+ coliphage and SRC were found to be more resistant than fecal coliforms for the tertiary treatment processes, they may prove to be more suitable as indicators for Giardia. The results of this study demonstrated that advanced wastewater treatment may prove efficient for the removal of Giardia cysts and may prevent its transmission when treated effluents are applied for crop irrigation or streams restoration.
-
Baert, Leen; Uyttendaele, Mieke; Vermeersch, Mattias; Van Coillie, Els; Debevere, Johan
2008-08-01
The reduction of murine norovirus 1 (MNV-1) on onions and spinach by washing was investigated as was the risk of contamination during the washing procedure. To decontaminate wash water, the industrial sanitizer peracetic acid (PAA) was added to the water, and the survival of MNV-1 was determined. In contrast to onions, spinach undergoes a heat treatment before freezing. Therefore, the resistance of MNV-1 to blanching of spinach was examined. MNV-1 genomic copies were detected with a real-time reverse transcription PCR assay in PAA-treated water and blanched spinach, and PFUs (representing infectious MNV-1 units) were determined with a plaque assay. A < or = 1-log reduction in MNV-1 PFUs was achieved by washing onion bulbs and spinach leaves. More than 3 log PFU of MNV-1 was transmitted to onion bulbs and spinach leaves when these vegetables were washed in water containing approximately 5 log PFU/ml. No decline of MNV-1 occurred in used industrial spinach wash water after 6 days at room temperature. A concentration of 20 ppm of PAA in demineralized water (pH 4.13) and in potable water (pH 7.70) resulted in reductions of 2.88 +/- 0.25 and 2.41 +/- 0.18 log PFU, respectively, after 5 min of exposure, but no decrease in number of genomic copies was observed. No reduction of MNV-1 PFUs was observed on frozen onions or spinach during storage for 6 months. Blanching spinach (80 degrees C for 1 min) resulted in at least 2.44-log reductions of infectious MNV-1, but many genomic copies were still present.
-
Ching, Emily S C; Lo, T S; Procaccia, Itamar
2006-08-01
Drag reduction by polymers is bounded between two universal asymptotes, the von Kármán log law of the law and the maximum drag reduction (MDR) asymptote. It is theoretically understood why the MDR asymptote is universal, independent of whether the polymers are flexible or rodlike. The crossover behavior from the Newtonian von Kármán log law to the MDR is, however, not universal, showing different characteristics for flexible and rodlike polymers. In this paper we provide a theory for this crossover phenomenology.
-
Traub-Dargatz, Josie L; Weese, J Scott; Rousseau, Joyce D; Dunowska, Magdalena; Morley, Paul S; Dargatz, David A
2006-07-01
Reduction factors (RFs) for bacterial counts on examiners' hands were compared when performing a standardized equine physical examination, followed by the use of one of 3 hand-hygiene protocols (washing with soap, ethanol gel application, and chlorohexidine-ethanol application). The mean RFs were 1.29 log10 and 1.44 log10 at 2 study sites for the alcohol-gel (62% ethyl alcohol active ingredient) protocols and 1.47 log10 and 1.94 log10 at 2 study sites for the chlorhexidine-alcohol (61% ethyl alcohol plus 1% chlorhexidine active ingredients) protocols, respectively. The RFs were significantly different (P < 0.0001) between the hand-washing group and the other 2 treatment groups (the alcohol-gel and the chlorhexidine-alcohol lotion). The use of alcohol-based gels or chlorhexidine-alcohol hand hygiene protocols must still be proven effective in equine practice settings, but in this study, these protocols were equivalent or superior to hand washing for reduction in bacterial load on the hands of people after they perform routine physical examinations.
-
Traub-Dargatz, Josie L.; Weese, J. Scott; Rousseau, Joyce D.; Dunowska, Magdalena; Morley, Paul S.; Dargatz, David A.
2006-01-01
Abstract Reduction factors (RFs) for bacterial counts on examiners’ hands were compared when performing a standardized equine physical examination, followed by the use of one of 3 hand-hygiene protocols (washing with soap, ethanol gel application, and chlorohexidine-ethanol application). The mean RFs were 1.29 log10 and 1.44 log10 at 2 study sites for the alcohol-gel (62% ethyl alcohol active ingredient) protocols and 1.47 log10 and 1.94 log10 at 2 study sites for the chlorhexidine-alcohol (61% ethyl alcohol plus 1% chlorhexidine active ingredients) protocols, respectively. The RFs were significantly different (P < 0.0001) between the hand-washing group and the other 2 treatment groups (the alcohol-gel and the chlorhexidine-alcohol lotion). The use of alcohol-based gels or chlorhexidine-alcohol hand hygiene protocols must still be proven effective in equine practice settings, but in this study, these protocols were equivalent or superior to hand washing for reduction in bacterial load on the hands of people after they perform routine physical examinations. PMID:16898109
-
Kotwal, Grishma; Harrison, Mark A.; Law, S. Edward; Harrison, Judy A.
2013-01-01
Human noroviruses are major etiologic agents of epidemic gastroenteritis. Outbreaks are often accompanied by contamination of environmental surfaces, but since these viruses cannot be routinely propagated in laboratory cultures, their response to surface disinfectants is predicted by using surrogates, such as murine norovirus 1 (MNV-1). This study compared the virucidal efficacies of various liquid treatments (three sanitizer liquids, 5% levulinic acid plus 2% SDS [LEV/SDS], 200 ppm chlorine, and an isopropanol-based quaternary ammonium compound [Alpet D2], and two control liquids, sterile tap water and sterile tap water plus 2% SDS) when delivered to MNV-1-inoculated stainless steel surfaces by conventional hydraulic or air-assisted, induction-charged (AAIC) electrostatic spraying or by wiping with impregnated towelettes. For the spray treatments, LEV/SDS proved effective when applied with hydraulic and AAIC electrostatic spraying, providing virus reductions of 2.71 and 1.66 log PFU/ml, respectively. Alpet D2 provided a 2.23-log PFU/ml reduction with hydraulic spraying, outperforming chlorine (1.16-log PFU/ml reduction). Chlorine and LEV/SDS were equally effective as wipes, reducing the viral load by 7.05 log PFU/ml. Controls reduced the viral load by <1 log with spraying applications and by >3 log PFU/ml with wiping. Results indicated that both sanitizer type and application methods should be carefully considered when choosing a surface disinfectant to best prevent and control environmental contamination by noroviruses. PMID:23263949
-
Feroz, Farahnaaz; Shimizu, Hiromi; Nishioka, Terumi; Mori, Miho; Sakagami, Yoshikazu
2016-01-01
Food is a basic necessity for human survival, but it is still the vehicle for the transmission of food borne disease. Various studies have examined the roles of spices, herbs, nuts, and semi-dried fruits, making the need for safe and convenient methods of decontamination a necessity. The current study determined the bacterial and fungal loads of 26 spices and herbs, 5 nuts, 10 semi-dried fruits and 5 other foods. Spices, herbs and semi-dried foods demonstrated the highest bacterial and fungal loads with the majority showing over 10 4 CFU/mL. Nuts and other foods showed growths ranging from 10 2 to 10 6 CFU/mL. The current study also attempted to determine the effects of heat and plasma treatment. The log reduction of bacterial growth after heat treatment (maximum: 120 min for 60℃) was between 0.08 to 4.47, and the log reduction after plasma treatment (maximum: 40 min) ranged from 2.37 to 5.75. Spices showed the lowest rates of reduction, whereas the semi-dried and other foods showed moderate to high levels of decrease after heat treatment. The log reduction of fungal growth after heat treatment ranged from 0.27 to 4.40, and log reduction after plasma treatment ranged from 2.15 to 5.91．Furthermore, we validated the sterilization effect of plasma treatment against Bacillus spp. and Staphylococcus spp. by using scanning electron microscopy. Both treatment methods could prove to be advantageous in the agriculture related fields, enhancing the quality of the foods.
-
Ammonia sanitization of blackwater for safe use as fertilizer.
Fidjeland, Jörgen; Svensson, Sven-Erik; Vinnerås, Björn
2015-01-01
Source-separated blackwater from low-flush toilets contains plant-available nutrients and can be used as a fertilizer. The aim of the study was to evaluate the impact on pathogen inactivation when treating blackwater with urea and/or lime. Blackwater was spiked with Salmonella typhimurium, Escherichia coli O157, Enterococcus faecalis, and Ascaris suum eggs, and treated with urea and/or lime in concentrations up to 0.1% w/w. The bottles were kept in a storage facility (manure slurry tank) for 102 days while monitoring the pathogen concentrations. The treatment time needed to meet the requirement for Salmonella and E. coli reduction could be reduced at least six-fold. The enterococci were more persistent, and only the highest treatment doses had a significantly higher inactivation than the controls. The Ascaris egg viability was only reduced by around 50%, so higher urea/lime doses and/or longer treatment times are required to fulfill the treatment requirements of 3 log10 reductions of parasite eggs.
-
Benchmarking the minimum Electron Beam (eBeam) dose required for the sterilization of space foods
NASA Astrophysics Data System (ADS)
Bhatia, Sohini S.; Wall, Kayley R.; Kerth, Chris R.; Pillai, Suresh D.
2018-02-01
As manned space missions extend in length, the safety, nutrition, acceptability, and shelf life of space foods are of paramount importance to NASA. Since food and mealtimes play a key role in reducing stress and boredom of prolonged missions, the quality of food in terms of appearance, flavor, texture, and aroma can have significant psychological ramifications on astronaut performance. The FDA, which oversees space foods, currently requires a minimum dose of 44 kGy for irradiated space foods. The underlying hypothesis was that commercial sterility of space foods could be achieved at a significantly lower dose, and this lowered dose would positively affect the shelf life of the product. Electron beam processed beef fajitas were used as an example NASA space food to benchmark the minimum eBeam dose required for sterility. A 15 kGy dose was able to achieve an approximately 10 log reduction in Shiga-toxin-producing Escherichia coli bacteria, and a 5 log reduction in Clostridium sporogenes spores. Furthermore, accelerated shelf life testing (ASLT) to determine sensory and quality characteristics under various conditions was conducted. Using Multidimensional gas-chromatography-olfactometry-mass spectrometry (MDGC-O-MS), numerous volatiles were shown to be dependent on the dose applied to the product. Furthermore, concentrations of off -flavor aroma compounds such as dimethyl sulfide were decreased at the reduced 15 kGy dose. The results suggest that the combination of conventional cooking combined with eBeam processing (15 kGy) can achieve the safety and shelf-life objectives needed for long duration space-foods.
-
Oughton, Matthew T; Loo, Vivian G; Dendukuri, Nandini; Fenn, Susan; Libman, Michael D
2009-10-01
To evaluate common hand hygiene methods for efficacy in removing Clostridium difficile. Randomized crossover comparison among 10 volunteers with hands experimentally contaminated by nontoxigenic C. difficile. Interventions included warm water with plain soap, cold water with plain soap, warm water with antibacterial soap, antiseptic hand wipes, alcohol-based handrub, and a control involving no intervention. All interventions were evaluated for mean reduction in colony-forming units (CFUs) under 2 contamination protocols: "whole hand" and "palmar surface." Results were analyzed according to a Bayesian approach, by using hierarchical models adjusted for multiple observations. Under the whole-hand protocol, the greatest adjusted mean reductions were achieved by warm water with plain soap (2.14 log(10) CFU/mL [95% credible interval (CrI), 1.74-2.54 log(10) CFU/mL]), cold water with plain soap (1.88 log(10) CFU/mL [95% CrI, 1.48-2.28 log(10) CFU/mL), and warm water with antibacterial soap (1.51 log(10) CFU/mL [95% CrI, 1.12-1.91 log(10) CFU/mL]), followed by antiseptic hand wipes (0.57 log(10) CFU/mL [95% CrI, 0.17-0.96 log(10) CFU/mL]). Alcohol-based handrub (0.06 log(10) CFU/mL [95% CrI, -0.34 to 0.45 log(10) CFU/mL]) was equivalent to no intervention. Under the palmar surface protocol, warm water with plain soap, cold water with plain soap, and warm water with antibacterial soap again yielded the greatest mean reductions, followed by antiseptic hand wipes (26.6, 26.6, 26.6, and 21.9 CFUs per plate, respectively), when compared with alcohol-based handrub. Hypothenar (odds ratio, 10.98 [95% CrI, 1.96-37.65]) and thenar (odds ratio, 6.99 [95% CrI, 1.25-23.41]) surfaces were more likely than fingertips to remain heavily contaminated after handwashing. Handwashing with soap and water showed the greatest efficacy in removing C. difficile and should be performed preferentially over the use of alcohol-based handrubs when contact with C. difficile is suspected or likely.
-
Walking training and cortisol to DHEA-S ratio in postmenopause: An intervention study.
Di Blasio, Andrea; Izzicupo, Pascal; Di Baldassarre, Angela; Gallina, Sabina; Bucci, Ines; Giuliani, Cesidio; Di Santo, Serena; Di Iorio, Angelo; Ripari, Patrizio; Napolitano, Giorgio
2018-04-01
The literature indicates that the plasma cortisol-to-dehydroepiandrosterone-sulfate (DHEA-S) ratio is a marker of health status after menopause, when a decline in both estrogen and DHEA-S and an increase in cortisol occur. An increase in the cortisol-to-DHEA-S ratio has been positively correlated with metabolic syndrome, all-cause mortality, cancer, and other diseases. The aim of this study was to investigate the effects of a walking program on the plasma cortisol-to-DHEA-S ratio in postmenopausal women. Fifty-one postmenopausal women participated in a 13-week supervised walking program, in the metropolitan area of Pescara (Italy), from June to September 2013. Participants were evaluated in April-May and September-October of the same year. The linear mixed model showed that the variation of the log 10 Cortisol-to-log 10 DHEA-S ratio was associated with the volume of exercise (p = .03). Participants having lower adherence to the walking program did not have a significantly modified log 10 Cortisol or log 10 DHEA-S, while those having the highest adherence had a significant reduction in log 10 Cortisol (p = .016) and a nearly significant increase in log 10 DHEA-S (p = .084). Walking training appeared to reduce the plasma log 10 Cortisol-to-log 10 DHEA-S ratio, although a minimum level of training was necessary to achieve this significant reduction.
-
Reduction in fecal excretion of Giardia cysts: effect of cholestasis and diet.
Erlandsen, Stanley
2005-12-01
Bile is a major growth factor for the proliferation of Giardia spp. trophozoites in the small intestine and, at high concentrations, stimulates encystment of trophozoites. This report demonstrates that surgical cholestasis to interrupt the flow of bile from liver to intestine or the use of bile-binding resins in the diet can both dramatically decrease the fecal excretion of Giardia muris cysts. Cholestasis produced a 3 log reduction in excretion of G. muris cysts within 24 hr of surgery and a 4 log reduction after 3 days. Sham controls showed no difference in cyst excretion from presurgical control values. Two isocaloric diets were studied: a control diet (N) of Purina mouse chow containing 5% celufil and an experimental diet (CR) containing 5% cholestyramine, a resin that binds bile. Compared with the N diet, the CR diet was associated with reductions in cyst excretion of 3 logs within 1 day. Despite lowered excretion of G. muris cysts in mice fed the cholestyramine diet, the trophozoite recovery from the duodenum was similar with both diets. Cyclic feeding of the CR diet and the N diet at 3-day intervals produced significant oscillations (changes of 3-4 logs) in fecal cyst shedding. The significant reductions in fecal excretion of cysts observed with agents that bind bile suggests that diets capable of binding bile might be a therapeutic means to minimize the fecal excretion of cysts and thereby may help to reduce the risk of spreading giardiasis through fecal-oral contamination.
-
Keskinen, Lindsey A; Burke, Angela; Annous, Bassam A
2009-06-30
This study compared the efficacy of chlorine (20-200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20-200 ppm chlorite ion concentration, Sanova), and aqueous chlorine dioxide (20-200 ppm chlorite ion concentration, TriNova) washes in reducing populations of Escherichia coli O157:H7 on artificially inoculated lettuce. Fresh-cut leaves of Romaine or Iceberg lettuce were inoculated by immersion in water containing E. coli O157:H7 (8 log CFU/ml) for 5 min and dried in a salad spinner. Leaves (25 g) were then washed for 2 min, immediately or following 24 h of storage at 4 degrees C. The washing treatments containing chlorite ion concentrations of 100 and 200 ppm were the most effective against E. coli O157:H7 populations on Iceberg lettuce, with log reductions as high as 1.25 log CFU/g and 1.05 log CFU/g for TriNova and Sanova wash treatments, respectively. All other wash treatments resulted in population reductions of less than 1 log CFU/g. Chlorine (200 ppm), TriNova, Sanova, and acidic electrolyzed water were all equally effective against E. coli O157:H7 on Romaine, with log reductions of approximately 1 log CFU/g. The 20 ppm chlorine wash was as effective as the deionized water wash in reducing populations of E. coli O157:H7 on Romaine and Iceberg lettuce. Scanning electron microscopy indicated that E. coli O157:H7 that was incorporated into biofilms or located in damage lettuce tissue remained on the lettuce leaf, while individual cells on undamaged leaf surfaces were more likely to be washed away.
-
Liu, Chengchu; Duan, Jingyun; Su, Yi-Cheng
2006-02-15
The effects of electrolyzed oxidizing (EO) water on reducing Listeria monocytogenes contamination on seafood processing surfaces were studied. Chips (5 x 5 cm(2)) of stainless steel sheet (SS), ceramic tile (CT), and floor tile (FT) with and without crabmeat residue on the surface were inoculated with L. monocytogenes and soaked in tap or EO water for 5 min. Viable cells of L. monocytogenes were detected on all chip surfaces with or without crabmeat residue after being held at room temperature for 1 h. Soaking contaminated chips in tap water resulted in small-degree reductions of the organism (0.40-0.66 log cfu/chip on clean surfaces and 0.78-1.33 log cfu/chip on dirty surfaces). Treatments of EO water significantly (p<0.05) reduced L. monocytogenes on clean surfaces (3.73 log on SS, 4.24 log on CT, and 5.12 log on FT). Presence of crabmeat residue on chip surfaces reduced the effectiveness of EO water on inactivating Listeria cells. However, treatments of EO water also resulted in significant reductions of L. monocytogenes on dirty surfaces (2.33 log on SS and CT and 1.52 log on FT) when compared with tap water treatments. The antimicrobial activity of EO water was positively correlated with its chlorine content. High oxidation-reduction potential (ORP) of EO water also contributed significantly to its antimicrobial activity against L. monocytogenes. EO water was more effective than chlorine water on inactivating L. monocytogenes on surfaces and could be used as a chlorine alternative for sanitation purpose. Application of EO water following a thorough cleaning process could greatly reduce L. monocytogenes contamination in seafood processing environments.
-
Flannery, J; Rajko-Nenow, P; Winterbourn, J B; Malham, S K; Jones, D L
2014-08-01
The aim of this study was to determine if domestic cooking practices can reduce concentrations of norovirus (NoV) and F-specific RNA (FRNA) bacteriophage in experimentally contaminated mussels. Mussels (n = 600) contaminated with NoV and FRNA bacteriophage underwent four different cooking experiments performed in triplicate at ~70°C and >90°C. Concentrations of infectious FRNA bacteriophage (using a plaque assay) were compared with concentrations of FRNA bacteriophage and NoV determined using a standardised RT-qPCR. Initial concentrations of infectious FRNA bacteriophage (7·05 log10 PFU g(-1) ) in mussels were not significantly reduced in simmering water (~70°C); however, cooking at higher temperatures (>90°C) reduced infectious FRNA bacteriophage to undetected levels within 3 min. Further investigation determined the time required for a 1-log reduction of infectious FRNA bacteriophage at 90°C to be 42 s therefore a >3-log reduction in infectious virus can be obtained by heating mussel digestive tissue to 90°C for 126 s. Domestic cooking practices based on shell opening alone do not inactivate infectious virus in mussels, however, cooking mussels at high temperatures is effective to reduce infectious virus concentrations and the risk of illness in consumers. The data will contribute towards evidence-based cooking recommendations for shellfish to provide a safe product for human consumption. © 2014 The Society for Applied Microbiology.
-
Virucides in apiculture: persistence of surrogate enterovirus under simulated field conditions.
Prodělalová, Jana; Malenovská, Hana; Moutelíková, Romana; Titěra, Dalibor
2017-12-01
Honeybee viruses have been recognized as being among the most important factors leading to colony losses worldwide. Colony food and faeces are regarded as possible sources of infectious viruses able to contaminate the environment and equipment of apiaries. Thus, methods for elimination of viruses are required. No cell culture assay for testing the effect of disinfectants on honeybee viruses is yet available. Therefore, surrogate virus was employed for testing of the efficacy of iodophor- and peracetic acid-based disinfectants in combination with six organic contaminants at +6 °C and +22 °C. Moreover, we evaluated the persistence of the surrogate in honey at +6 °C, +22 °C, and +50 °C. Iodophor-based disinfectant showed a maximum reduction of virus titre of 3.4 log 10 . Peracetic acid reduced the titre (≥4 log 10 ) only at 22 °C and without yeast extract/bovine serum albumin. After 25 days of incubation of the virus - honey mix, no decrease of virus titre was observed at +6 °C, whereas a significant reduction (3.5 log 10 ) was found at +50 °C already after 1 day. Both tested disinfectants can serve as appropriate virucides in apiaries. The effect of peracetic acid significantly depended on temperature and organic contaminants. The iodophor-based disinfectant showed a stable antiviral effect at different temperatures and with different contaminants. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.
-
Inactivation of Mycobacterium avium subsp. paratuberculosis during cooking of hamburger patties.
Hammer, Philipp; Walte, Hans-Georg C; Matzen, Sönke; Hensel, Jann; Kiesner, Christian
2013-07-01
The role of Mycobacterium avium subsp. paratuberculosis (MAP) in Crohn's disease in humans has been debated for many years. Milk and milk products have been suggested as possible vectors for transmission since the beginning of this debate, whereas recent publications show that slaughtered cattle and their carcasses, meat, and organs can also serve as reservoirs for MAP transmission. The objective of this study was to generate heat-inactivation data for MAP during the cooking of hamburger patties. Hamburger patties of lean ground beef weighing 70 and 50 g were cooked for 6, 5, 4, 3, and 2 min, which were sterilized by irradiation and spiked with three different MAP strains at levels between 10² and 10⁶ CFU/ml. Single-sided cooking with one flip was applied, and the temperatures within the patties were recorded by seven thermocouples. Counting of the surviving bacteria was performed by direct plating onto Herrold's egg yolk medium and a three-vial most-probable-number method by using modified Dubos medium. There was considerable variability in temperature throughout the patties during frying. In addition, the log reduction in MAP numbers showed strong variations. In patties weighing 70 g, considerable bacterial reduction of 4 log or larger could only be achieved after 6 min of cooking. For all other cooking times, the bacterial reduction was less than 2 log. Patties weighing 50 g showed a 5-log or larger reduction after cooking times of 5 and 6 min. To determine the inactivation kinetics, a log-linear regression model was used, showing a constant decrease of MAP numbers over cooking time.
-
Petterson, S; Roser, D; Deere, D
2015-09-01
It is proposed that the next revision of the Australian Drinking Water Guidelines will include 'health-based targets', where the required level of potable water treatment quantitatively relates to the magnitude of source water pathogen concentrations. To quantify likely Cryptosporidium concentrations in southern Australian surface source waters, the databases for 25 metropolitan water supplies with good historical records, representing a range of catchment sizes, land use and climatic regions were mined. The distributions and uncertainty intervals for Cryptosporidium concentrations were characterized for each site. Then, treatment targets were quantified applying the framework recommended in the World Health Organization Guidelines for Drinking-Water Quality 2011. Based on total oocyst concentrations, and not factoring in genotype or physiological state information as it relates to infectivity for humans, the best estimates of the required level of treatment, expressed as log10 reduction values, ranged among the study sites from 1.4 to 6.1 log10. Challenges associated with relying on historical monitoring data for defining drinking water treatment requirements were identified. In addition, the importance of quantitative microbial risk assessment input assumptions on the quantified treatment targets was investigated, highlighting the need for selection of locally appropriate values.
-
Lacombe, Alison; Niemira, Brendan A; Sites, Joseph; Boyd, Glenn; Gurtler, Joshua B; Tyrell, Breanna; Fleck, Melissa
2016-11-01
The disinfecting properties of high-intensity monochromatic blue light (MBL) were investigated against Escherichia coli O157:H7, Salmonella , and nonpathogenic bacteria inoculated onto the surface of almonds. MBL was generated from an array of narrow-band 405-nm light-emitting diodes. Almonds were inoculated with higher or lower levels (8 or 5 CFU/g) of pathogenic E. coli O157:H7 and Salmonella , as well as nonpathogenic E. coli K-12 and an avirulent strain of Salmonella Typhimurium, for evaluation as potential surrogates for their respective pathogens. Inoculated almonds were treated with MBL for 0, 1, 2, 4, 6, 8, and 10 min at a working distance of 7 cm. Simultaneous to treatment, cooling air was directed onto the almonds at a rate of 4 ft 3 /min (1.89 ×10 -3 m 3 /s), sourced through a container of dry ice. An infrared camera was used to monitor the temperature readings after each run. For E. coli K-12, reductions of up to 1.85 or 1.63 log CFU/g were seen for higher and lower inoculum levels, respectively; reductions up to 2.44 and 1.44 log CFU/g were seen for E. coli O157:H7 (higher and lower inoculation levels, respectively). Attenuated Salmonella was reduced by up to 0.54 and 0.97 log CFU/g, whereas pathogenic Salmonella was reduced by up to 0.70 and 0.55 log CFU/g (higher and lower inoculation levels, respectively). Inoculation level did not significantly impact minimum effective treatment times, which ranged from 1 to 4 min. Temperatures remained below ambient throughout treatment, indicating that MBL is a nonthermal antimicrobial process. The nonpathogenic strains of E. coli and Salmonella each responded to MBL in a comparable manner to their pathogenic counterparts. These results suggest that these nonpathogenic strains may be useful in experiments with MBL in which a surrogate is required, and that MBL warrants further investigation as a potential antimicrobial treatment for low-moisture foods.
-
Pangloli, Philipus; Hung, Yen-Con; Beuchat, Larry R; King, C Harold; Zhao, Zhi-Hui
2009-09-01
Treatment of fresh fruits and vegetables with electrolyzed water (EW) has been shown to kill or reduce foodborne pathogens. We evaluated the efficacy of EW in killing Escherichia coli O157:H7 on iceberg lettuce, cabbage, lemons, and tomatoes by using washing and/or chilling treatments simulating those followed in some food service kitchens. Greatest reduction levels on lettuce were achieved by sequentially washing with 14-A (amperage) acidic EW (AcEW) for 15 or 30 s followed by chilling in 16-A AcEW for 15 min. This procedure reduced the pathogen by 2.8 and 3.0 log CFU per leaf, respectively, whereas washing and chilling with tap water reduced the pathogen by 1.9 and 2.4 log CFU per leaf. Washing cabbage leaves for 15 or 30 s with tap water or 14-A AcEW reduced the pathogen by 2.0 and 3.0 log CFU per leaf and 2.5 to 3.0 log CFU per leaf, respectively. The pathogen was reduced by 4.7 log CFU per lemon by washing with 14-A AcEW and 4.1 and 4.5 log CFU per lemon by washing with tap water for 15 or 30 s. A reduction of 5.3 log CFU per lemon was achieved by washing with 14-A alkaline EW for 15 s prior to washing with 14-A AcEW for 15 s. Washing tomatoes with tap water or 14-A AcEW for 15 s reduced the pathogen by 6.4 and 7.9 log CFU per tomato, respectively. Application of AcEW using procedures mimicking food service operations should help minimize cross-contamination and reduce the risk of E. coli O157:H7 being present on produce at the time of consumption.
-
Horm, Katie Marie; D'Souza, Doris Helen
2011-08-01
Fresh fruits, juices, and beverages have been implicated in human noroviral and hepatitis A virus outbreaks. The purpose of this study was to determine the survival of human norovirus surrogates (murine norovirus, MNV-1; feline calicivirus, FCV-F9; and bacteriophage MS2) in juices (orange and pomegranate juices), juice blends (pomegranate and orange juice) and milk over 0, 1, 2, 7, 14, and 21 days at refrigeration (4 °C). Juices, juice blends, and milk were inoculated with each virus over 21 days, serially diluted in cell culture media, and plaque assayed. MNV-1 showed no reduction in titer after 21 days in orange juice and milk, but moderate reduction (1.4 log) in pomegranate juice from a titer of 5 log(10) PFU/ml. However, MNV-1 was completely reduced after 7 days in the orange and pomegranate juice blend. FCV-F9 from a titer of 6 log(10) PFU/ml was completely reduced after 14 days in orange as well as pomegranate juice and by ∼ 3 logs after 21 days in milk at 4 °C. Interestingly, FCV-F9 was completely reduced after 1 day in the orange and pomegranate juice blend at 4 °C. MS2 was reduced by ∼ 1.28 log after 21 days in orange juice from a titer of 6 log(10) PFU/ml, and <1 log after 21 days in milk or pomegranate juice, with juice blends showing minimal reduction (<1 log) after 21 days at 4 °C. These results show the survival pattern of noroviruses that aid in the transmission of foodborne viral outbreaks. The data obtained can be used in quantitative viral risk assessment studies and to develop improved measures to prevent virus survival towards controlling outbreaks. Copyright © 2011. Published by Elsevier Ltd.
-
Park, Shin Young; Ha, Sang-Do
2018-01-01
This study investigated the synergistic effects of sodium hypochlorite (NaClO) and gamma irradiation combination against Vibrio parahaemolyticus in shucked oysters and clams. V. parahaemolyticus decreased to 1.1-5.6 log 10 CFU/g in oysters and 1.1-5.7 log 10 CFU/g in clams by NaClO (20-80 ppm) + γ irradiation (0.1-2.0 kGy) combinations. V. parahaemolyticus was not detected by 60 or 80 ppm NaClO + 2.0 kGy. Synergistic reduction of >1 log was observed by 60 ppm NaClO + 0.3-2 kGy and 80 ppm NaClO + 0.5 or 2 kGy. Specifically, >2 log of the synergistic reduction was obtained by 60 or 80 ppm NaClO + 2 kGy. Furthermore, using the Weibull model, 5D values (5-log reductions) were calculated for 60 or 80 ppm NaClO + 0.5-0.9 kGy. No significant differences were observed for all sensory parameters between samples of 2.0 kGy + 0-80 ppm NaClO. This study suggests that 60 ppm NaClO + 2.0 kGy in reducing 7-log V. parahaemolyticus without any deteriorative changes of sensory qualities could be a potential strategy for post-harvest process in seafood processing and distribution to enhance the microbial safety of molluscan shellfish.
-
Jeyapalan, Vidhya; Krishnan, Chitra Shankar; Ramasubramanian, Hariharan; Sampathkumar, Jayakrishnakumar; Azhagarasan, N S; Krishnan, Madhusudan
2016-07-06
To comparatively evaluate the antimicrobial efficacy of freshly prepared electrolyzed oxidizing water (EOW) with that of 2.4% glutaraldehyde (GA) and 1% sodium hypochlorite (SH) on clinically derived poly vinyl siloxane (PVS) impressions. Four clinically derived PVS impressions each were obtained from 10 subjects. One impression from each subject was randomly kept as control (group I), without disinfection. The remaining three impressions were randomly disinfected by immersion in either 2.4% GA (group II), 1% SH (group III), or freshly prepared EOW (group IV). The samples were subjected to microbial culture individually on brain heart infusion (BHI) agar medium. The organisms isolated were confirmed by visual examination and gram staining. Mean colony forming units (CFU) were counted, log 10 reduction obtained and compared. Data were statistically analyzed using one-way ANOVA, followed by multiple comparisons using Tukey-HSD post hoc tests (p < 0.05). Streptococci, Staphylococci, Pseudomonas, Candida, Proteus, Klebsiella, and E. coli were isolated from all impressions including the controls, except those disinfected by EOW. All three disinfectants showed significant reduction in CFU and log 10 reduction values as compared to the controls. EOW showed significantly higher reduction in log 10 values compared to GA and SH, whereas GA and SH showed similar reductions. EOW, GA, and SH showed kill rates of 100%, 99.60%, and 99.82%, respectively. EOW showed significant antimicrobial efficacy as evidenced by reduction in log 10 values when used as an immersion disinfectant for PVS impressions when compared with the results obtained using GA and SH. These results need further investigation. EOW shows high antimicrobial efficacy when used as an immersion disinfectant as compared to GA and SH for clinically derived PVS impressions. © 2016 by the American College of Prosthodontists.
-
Removal of indicator organisms by chemical treatment of wastewater.
De Zutter, L; van Hoof, J
1981-01-01
Recently a new chemical wastewater treatment process based upon precipitation of proteins by sodium lignosulphonate under acid conditions is used to purify the wastewater from slaughterhouses and poultry processing plants. In order to determine the reduction of indicator organisms due to this treatment process, influent and effluent samples from two of such plants (plant A in a pig slaughterhouse and plant B in a poultry processing plant) were examined. The results demonstrated that the pH used in the process, has a considerable influence on the reduction of the indicator organisms. On the first sampling day in plant A the initial working-pH was 4 and the corresponding reduction of the different microorganisms varied from 0.7 to 1.5 log. According to the decrease of the pH to 2.3, the reduction increased to a minimum of at least 1.9 and a maximum of at least 4.5 log. In the other samples from this plant (working-pH 2.4) the elimination ranged from 1.8 to 4.0 log. In plant B, the removal of the indicator organisms brought about by a working-pH of 3.0 ranged from 2.1 to 3.1 log. The results showed that in comparison with the biological treatment processes this chemical wastewater treatment process realized a significant greater removal of indicator organisms.
-
Nicholas, R; Dunton, P; Tatham, A; Fielding, L
2013-08-01
The effects of gaseous ozone and open air factor (OAF) on environmental Listeria monocytogenes attached to three common food contact surfaces were investigated. Listeria monocytogenes on different food contact surfaces was treated with ozone and OAF. Microbiological counts, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed. Ozone at 10 ppm gave <1-log reduction when L. monocytogenes was attached to stainless steel, while 45 ppm gave a log reduction of 3.41. OAF gave better log reductions than 10 ppm ozone, but lower log reductions than 45 ppm. Significant differences were found between surfaces. Biofilm organisms were significantly more resistant than those surface attached on stainless steel. SEM and AFM demonstrated different membrane and cell surface modifications following ozone or OAF treatment. The strain used demonstrated higher resistance to ozone than previous studies. This may be due to the fact that it was isolated from a food manufacturing premises that used oxidizing disinfectants. OAF was more effective at reducing the levels of the organism than an ozone concentration of 10 ppm. Pathogen management strategies must account for resistance of environmental strains when validating cleaning and disinfection. OAF has shown potential for surface decontamination compared with ozone. SEM and AFM are valuable tools for determining mechanisms of action of antimicrobial agents. © 2013 The Society for Applied Microbiology.
-
Disinfection of bacteriophage MS2 by copper in water.
Armstrong, Andrew M; Sobsey, Mark D; Casanova, Lisa M
2017-09-01
Households that lack piped water supply are often forced to meet water needs by storing in the home, leaving water vulnerable to contamination by viruses. Storage in copper containers can potentially prevent this type of contamination, but the inactivation kinetics of viruses by copper need to be described to make appropriate storage recommendations. This work characterized inactivation kinetics of bacteriophage MS2 as a surrogate for enteric viruses by dissolved ionic copper in water. Reduction of MS2 increased with increasing doses of copper. At 0.3 mg/L, there was a 1.8-log 10 reduction of MS2 within 6 h. At 1 and 3 mg/L, 2-2.5 log 10 inactivation could be achieved between 6 and 24 h. Parameters for the Chick-Watson, Hom, and One Hit-Two Population models of inactivation were calculated and evaluated, all of which demonstrated strong goodness-of-fit and predictability at various contact times. Copper inactivates MS2 under controlled conditions at doses between 0.3 and 3 mg/L. Although requiring longer contact times than conventional disinfectants, it is a candidate for improving the safety of stored drinking water.
-
Kinetics of inactivation of indicator pathogens during thermophilic anaerobic digestion.
Popat, Sudeep C; Yates, Marylynn V; Deshusses, Marc A
2010-12-01
Thermophilic anaerobic sludge digestion is a promising process to divert waste to beneficial use, but an important question is the required temperature and holding time to achieve a given degree of pathogen inactivation. In this study, the kinetics of inactivation of Ascaris suum and vaccine strain poliovirus type 1 (PVS-1), selected as indicators for helminth ova and enteric viruses respectively, were determined during anaerobic digestion at temperatures ranging from 51 to 56 °C. Inactivation of both indicator organisms was fast with greater than two log reductions achieved within 2 h for A. suum and three log reductions for PVS-1, suggesting that the current U.S. regulations are largely conservative. The first-order inactivation rate constants k followed Arrhenius relationship with activation energies of 105 and 39 KJ mol(-1) for A. suum and PVS-1, respectively indicating that A. suum was more sensitive to temperature. Although inactivation was fast, the presence of compounds in the sludge that are known to be protective of pathogen inactivation was observed, suggesting that composition-dependent time-temperature relationships are necessary. Copyright © 2010 Elsevier Ltd. All rights reserved.
-
Integrase inhibitors in late pregnancy and rapid HIV viral load reduction.
Rahangdale, Lisa; Cates, Jordan; Potter, JoNell; Badell, Martina L; Seidman, Dominika; Miller, Emilly S; Coleman, Jenell S; Lazenby, Gweneth B; Levison, Judy; Short, William R; Yawetz, Sigal; Ciaranello, Andrea; Livingston, Elizabeth; Duthely, Lunthita; Rimawi, Bassam H; Anderson, Jean R; Stringer, Elizabeth M
2016-03-01
Minimizing time to HIV viral suppression is critical in pregnancy. Integrase strand transfer inhibitors (INSTIs), like raltegravir, are known to rapidly suppress plasma HIV RNA in nonpregnant adults. There are limited data in pregnant women. We describe time to clinically relevant reduction in HIV RNA in pregnant women using INSTI-containing and non-INSTI-containing antiretroviral therapy (ART) options. We conducted a retrospective cohort study of pregnant HIV-infected women in the United States from 2009 through 2015. We included women who initiated ART, intensified their regimen, or switched to a new regimen due to detectable viremia (HIV RNA >40 copies/mL) at ≥20 weeks gestation. Among women with a baseline HIV RNA permitting 1-log reduction, we estimated time to 1-log RNA reduction using the Kaplan-Meier estimator comparing women starting/adding an INSTI in their regimen vs other ART. To compare groups with similar follow-up time, we also conducted a subgroup analysis limited to women with ≤14 days between baseline and follow-up RNA data. This study describes 101 HIV-infected pregnant women from 11 US clinics. In all, 75% (76/101) of women were not taking ART at baseline; 24 were taking non-INSTI containing ART, and 1 received zidovudine monotherapy. In all, 39% (39/101) of women started an INSTI-containing regimen or added an INSTI to their ART regimen. Among 90 women with a baseline HIV RNA permitting 1-log reduction, the median time to 1-log RNA reduction was 8 days (interquartile range [IQR], 7-14) in the INSTI group vs 35 days (IQR, 20-53) in the non-INSTI ART group (P < .01). In a subgroup of 39 women with first and last RNA measurements ≤14 days apart, median time to 1-log reduction was 7 days (IQR, 6-10) in the INSTI group vs 11 days (IQR, 10-14) in the non-INSTI group (P < .01). ART that includes INSTIs appears to induce more rapid viral suppression than other ART regimens in pregnancy. Inclusion of an INSTI may play a role in optimal reduction of HIV RNA for HIV-infected pregnant women presenting late to care or failing initial therapy. Larger studies are urgently needed to assess the safety and effectiveness of this approach. Copyright © 2016 Elsevier Inc. All rights reserved.
-
Jensen, Dane A; Macinga, David R; Shumaker, David J; Bellino, Roberto; Arbogast, James W; Schaffner, Donald W
2017-06-01
The literature on hand washing, while extensive, often contains conflicting data, and key variables are only superficially studied or not studied at all. Some hand washing recommendations are made without scientific support, and agreement between recommendations is limited. The influence of key variables such as soap volume, lather time, water temperature, and product formulation on hand washing efficacy was investigated in the present study. Baseline conditions were 1 mL of a bland (nonantimicrobial) soap, a 5-s lather time, and 38°C (100°F) water temperature. A nonpathogenic strain of Escherichia coli (ATCC 11229) was the challenge microorganism. Twenty volunteers (10 men and 10 women) participated in the study, and each test condition had 20 replicates. An antimicrobial soap formulation (1% chloroxylenol) was not significantly more effective than the bland soap for removing E. coli under a variety of test conditions. Overall, the mean reduction was 1.94 log CFU (range, 1.83 to 2.10 log CFU) with the antimicrobial soap and 2.22 log CFU (range, 1.91 to 2.54 log CFU) with the bland soap. Overall, lather time significantly influenced efficacy in one scenario, in which a 0.5-log greater reduction was observed after 20 s with bland soap compared with the baseline wash (P = 0.020). Water temperature as high as 38°C (100°F) and as low as 15°C (60°F) did not have a significant effect on the reduction of bacteria during hand washing; however, the energy usage differed between these temperatures. No significant differences were observed in mean log reductions experienced by men and women (both 2.08 log CFU; P = 0.988). A large part of the variability in the data was associated with the behaviors of the volunteers. Understanding what behaviors and human factors most influence hand washing may help researchers find techniques to optimize the effectiveness of hand washing.
-
Reduction of spiked porcine circovirus during the manufacture of a Vero cell-derived vaccine.
Lackner, Cornelia; Leydold, Sandra M; Modrof, Jens; Farcet, Maria R; Grillberger, Leopold; Schäfer, Birgit; Anderle, Heinz; Kreil, Thomas R
2014-04-11
Porcine circovirus-1 (PCV1) was recently identified as a contaminant in live Rotavirus vaccines, which was likely caused by contaminated porcine trypsin. The event triggered the development of new regulatory guidance on the use of porcine trypsin which shall ensure that cell lines and porcine trypsin in use are free from PCV1. In addition, manufacturing processes of biologicals other than live vaccines include virus clearance steps that may prevent and mitigate any potential virus contamination of product. In this work, artificial spiking of down-scaled models for the manufacturing process of an inactivated pandemic influenza virus vaccine were used to investigate inactivation of PCV1 and the physico-chemically related porcine parvovirus (PPV) by formalin and ultraviolet-C (UV-C) treatment as well as removal by the purification step sucrose gradient ultracentrifugation. A PCV1 infectivity assay, using a real-time PCR infectivity readout was established. The formalin treatment (0.05% for 48h) showed substantial inactivation for both PCV1 and PPV with reduction factors of 3.0log10 and 6.8log10, respectively, whereas UV-C treatment resulted in complete PPV (≥5.9log10) inactivation already at a dose of 13mJ/cm but merely 1.7log10 at 24mJ/cm(2) for PCV1. The UV-C inactivation results with PPV were confirmed using minute virus of mice (MVM), indicating that parvoviruses are far more sensitive to UV-C than PCV1. The sucrose density gradient ultracentrifugation also contributed to PCV1 clearance with a reduction factor of 2log10. The low pH treatment during the production of procine trypsin was investigated and showed effective inactivation for both PCV1 (4.5log10) and PPV (6.4log10). In conclusion, PCV1 in general appears to be more resistant to virus inactivation than PPV. Still, the inactivated pandemic influenza vaccine manufacturing process provides for robust virus reduction, in addition to the already implemented testing for PCV1 to avoid any contaminations. Copyright © 2014 Elsevier Ltd. All rights reserved.
-
Nguyen, Hoang Anh; Denis, Olivier; Vergison, Anne; Theunis, Anne; Tulkens, Paul M; Struelens, Marc J; Van Bambeke, Françoise
2009-04-01
Small-colony variant (SCV) strains of Staphylococcus aureus show reduced antibiotic susceptibility and intracellular persistence, potentially explaining therapeutic failures. The activities of oxacillin, fusidic acid, clindamycin, gentamicin, rifampin, vancomycin, linezolid, quinupristin-dalfopristin, daptomycin, tigecycline, moxifloxacin, telavancin, and oritavancin have been examined in THP-1 macrophages infected by a stable thymidine-dependent SCV strain in comparison with normal-phenotype and revertant isogenic strains isolated from the same cystic fibrosis patient. The SCV strain grew slowly extracellularly and intracellularly (1- and 0.2-log CFU increase in 24 h, respectively). In confocal and electron microscopy, SCV and the normal-phenotype bacteria remain confined in acid vacuoles. All antibiotics tested, except tigecycline, caused a net reduction in bacterial counts that was both time and concentration dependent. At an extracellular concentration corresponding to the maximum concentration in human serum (total drug), oritavancin caused a 2-log CFU reduction at 24 h; rifampin, moxifloxacin, and quinupristin-dalfopristin caused a similar reduction at 72 h; and all other antibiotics had only a static effect at 24 h and a 1-log CFU reduction at 72 h. In concentration dependence experiments, response to oritavancin was bimodal (two successive plateaus of -0.4 and -3.1 log CFU); tigecycline, moxifloxacin, and rifampin showed maximal effects of -1.1 to -1.7 log CFU; and the other antibiotics produced results of -0.6 log CFU or less. Addition of thymidine restored intracellular growth of the SCV strain but did not modify the activity of antibiotics (except quinupristin-dalfopristin). All drugs (except tigecycline and oritavancin) showed higher intracellular activity against normal or revertant phenotypes than against SCV strains. The data may help rationalizing the design of further studies with intracellular SCV strains.
-
DOE Office of Scientific and Technical Information (OSTI.GOV)
Epstein, J.B.; McBride, B.C.; Stevenson-Moore, P.
Xerostomia may develop in patients with cancer who receive radiotherapy that includes the salivary glands in the field. These patients are at high risk of rampant dental caries. Streptococcus mutans and Lactobacillus species have been associated with dental caries. Quantitative counts of these organisms demonstrated high caries risk due to streptococci in 66% and due to lactobacilli in 100% of patients studied. Use of chlorhexidine rinse was shown to reduce S. mutans counts 1.1 logs and lactobacilli 1.1 logs. The use of chlorhexidine gel resulted in a reduction of S. mutans 1.2 logs and lactobacilli 2.2 logs. In the subjectsmore » using the rinse, caries risk due to streptococci was reduced to low levels in 44% and due to lactobacilli in only one subject, with reduction to moderate risk in one third and no change in risk in the remaining patients. The use of chlorhexidine gel was found to reduce the caries risk associated with streptococci to low levels in all patients, and the risk associated with lactobacilli to low and moderate risk in two thirds of patients.« less
-
Endogenous System Microbes as Treatment Process ...
Monitoring the efficacy of treatment strategies to remove pathogens in decentralized systems remains a challenge. Evaluating log reduction targets by measuring pathogen levels is hampered by their sporadic and low occurrence rates. Fecal indicator bacteria are used in centralized systems to indicate the presence of fecal pathogens, but are ineffective decentralized treatment process indicators as they generally occur at levels too low to assess log reduction targets. System challenge testing by spiking with high loads of fecal indicator organisms, like MS2 coliphage, has limitations, especially for large systems. Microbes that are endogenous to the decentralized system, occur in high abundances and mimic removal rates of bacterial, viral and/or parasitic protozoan pathogens during treatment could serve as alternative treatment process indicators to verify log reduction targets. To identify abundant microbes in wastewater, the bacterial and viral communities were examined using deep sequencing. Building infrastructure-associated bacteria, like Zoogloea, were observed as dominant members of the bacterial community in graywater. In blackwater, bacteriophage of the order Caudovirales constituted the majority of contiguous sequences from the viral community. This study identifies candidate treatment process indicators in decentralized systems that could be used to verify log removal during treatment. The association of the presence of treatment process indic
-
Naficy, Cameron; Sala, Anna; Keeling, Eric G; Graham, Jon; DeLuca, Thomas H
2010-10-01
Increased forest density resulting from decades of fire exclusion is often perceived as the leading cause of historically aberrant, severe, contemporary wildfires and insect outbreaks documented in some fire-prone forests of the western United States. Based on this notion, current U.S. forest policy directs managers to reduce stand density and restore historical conditions in fire-excluded forests to help minimize high-severity disturbances. Historical logging, however, has also caused widespread change in forest vegetation conditions, but its long-term effects on vegetation structure and composition have never been adequately quantified. We document that fire-excluded ponderosa pine forests of the northern Rocky Mountains logged prior to 1960 have much higher average stand density, greater homogeneity of stand structure, more standing dead trees and increased abundance of fire-intolerant trees than paired fire-excluded, unlogged counterparts. Notably, the magnitude of the interactive effect of fire exclusion and historical logging substantially exceeds the effects of fire exclusion alone. These differences suggest that historically logged sites are more prone to severe wildfires and insect outbreaks than unlogged, fire-excluded forests and should be considered a high priority for fuels reduction treatments. Furthermore, we propose that ponderosa pine forests with these distinct management histories likely require distinct restoration approaches. We also highlight potential long-term risks of mechanical stand manipulation in unlogged forests and emphasize the need for a long-term view of fuels management.
-
Chromatographic removal combined with heat, acid and chaotropic inactivation of four model viruses.
Valdés, R; Ibarra, Neysi; Ruibal, I; Beldarraín, A; Noa, E; Herrera, N; Alemán, R; Padilla, S; Garcia, J; Pérez, M; Morales, R; Chong, E; Reyes, B; Quiñones, Y; Agraz, A; Herrera, L
2002-07-03
The virus removal of protein A affinity chromatography, inactivation capacity, acid pH and a combination of high temperature with a chaotropic agent was determined in this work. The model viruses studied were sendaivirus, human immunodeficency virus (HIV-IIIb), human poliovirus type-II, human herpesvirus I and canine parvovirus. The protein A affinity chromatography showed a maximum reduction factor of 8 logs in the case of viruses larger than 120 nm size, while for small viruses (18-30 nm) the maximum reduction factor was about 5 logs. Non viral inactivation was observed during the monoclonal antibody elution step. Low pH treatment showed a maximum inactivation factor of 7.1 logs for enveloped viruses. However, a weak inactivation factor (3.4 logs) was obtained for DNA nonenveloped viruses. The combination of high temperature with 3 M KSCN showed a high inactivation factor for all of the viruses studied. The total clearance factor was 23.1, 15.1, 13.6, 20.0 and 16.0 logs for sendaivirus, HIV-IIIb, human poliovirus type-II, human herpesvirus I and canine parvovirus, respectively.
-
Garcés-Vega, Francisco; Marks, Bradley P
2014-08-01
In the last 20 years, the use of microbial reduction models has expanded significantly, including inactivation (linear and nonlinear), survival, and transfer models. However, a major constraint for model development is the impossibility to directly quantify the number of viable microorganisms below the limit of detection (LOD) for a given study. Different approaches have been used to manage this challenge, including ignoring negative plate counts, using statistical estimations, or applying data transformations. Our objective was to illustrate and quantify the effect of negative plate count data management approaches on parameter estimation for microbial reduction models. Because it is impossible to obtain accurate plate counts below the LOD, we performed simulated experiments to generate synthetic data for both log-linear and Weibull-type microbial reductions. We then applied five different, previously reported data management practices and fit log-linear and Weibull models to the resulting data. The results indicated a significant effect (α = 0.05) of the data management practices on the estimated model parameters and performance indicators. For example, when the negative plate counts were replaced by the LOD for log-linear data sets, the slope of the subsequent log-linear model was, on average, 22% smaller than for the original data, the resulting model underpredicted lethality by up to 2.0 log, and the Weibull model was erroneously selected as the most likely correct model for those data. The results demonstrate that it is important to explicitly report LODs and related data management protocols, which can significantly affect model results, interpretation, and utility. Ultimately, we recommend using only the positive plate counts to estimate model parameters for microbial reduction curves and avoiding any data value substitutions or transformations when managing negative plate counts to yield the most accurate model parameters.
-
Comes, Justin E; Beelman, Robert B
2002-03-01
A study was conducted to develop a preservative treatment capable of the Food and Drug Administration-mandated 5-log reduction of Escherichia coli O157:H7 populations in apple cider. Unpreserved apple cider was treated with generally recognized as safe acidulants and preservatives before inoculation with E. coli O157:H7 in test tubes and subjected to mild heat treatments (25, 35, and 45 degrees C) followed by refrigerated storage (4 degrees C). Fumaric acid had significant (P < 0.05) bactericidal effect when added to cider at 0.10% (wt/vol) and adjusted to pH 3.3, but citric and malic acid had no effect. Strong linear correlation (R2 = 0.96) between increasing undissociated fumaric acid concentrations and increasing log reductions of E. coli O157:H7 in apple cider indicated the undissociated acid to be the bactericidal form. The treatment that achieved the 5-log reduction in three commercial ciders was the addition of fumaric acid (0.15%, wt/vol) and sodium benzoate (0.05%, wt/vol) followed by holding at 25 degrees C for 6 h before 24 h of refrigeration at 4 degrees C. Subsequent experiments revealed that the same preservatives added to cider in flasks resulted in a more than 5-log reduction in less than 5 and 2 h when held at 25 and 35 degrees C, respectively. The treatment also significantly (P < 0.05) reduced total aerobic counts in commercial ciders to populations less than those of pasteurized and raw ciders from the same source (after 5 and 21 days of refrigerated storage at 4 degrees C, respectively). Sensory evaluation of the same ciders revealed that consumers found the preservative-treated cider to be acceptable.
-
The PK/PD Interactions of Doxycycline against Mycoplasma gallisepticum
Zhang, Nan; Gu, Xiaoyan; Ye, Xiaomei; Wu, Xun; Zhang, Bingxu; Zhang, Longfei; Shen, Xiangguang; Jiang, Hongxia; Ding, Huanzhong
2016-01-01
Mycoplasma gallisepticum is one of the most important pathogens that cause chronic respiratory disease in chicken. This study investigated the antibacterial activity of doxycycline against M. gallisepticum strain S6. In static time–killing studies with constant antibiotic concentrations [0–64 minimum inhibitory concentration (MIC)], M. gallisepticum colonies were quantified and kill rates were calculated to estimate the drug effect. The half-life of doxycycline in chicken was 6.51 ± 0.63 h. An in vitro dynamic model (the drug concentrations are fluctuant) was also established and two half-lives of 6.51 and 12 h were simulated. The samples were collected for drug concentration determination and viable counting of M. gallisepticum. In static time–killing studies, doxycycline produced a maximum antimycoplasmal effect of 5.62log10 (CFU/mL) reduction and the maximum kill rate was 0.11 h−1. In the in vitro dynamic model, doxycycline had a mycoplasmacidal activity in the two regimens, and the maximum antimycoplasmal effects were 4.1 and 4.75log10 (CFU/mL) reduction, respectively. Furthermore, the cumulative percentage of time over a 48-h period that the drug concentration exceeds the MIC (%T > MIC) was the pharmacokinetic–pharmacodynamic index that best correlated with antimicrobial efficacy (R2 = 0.986, compared with 0.897 for the peak level divided by the MIC and 0.953 for the area under the concentration–time curve over 48 h divided by the MIC). The estimated %T > MIC values for 0log10 (CFU/mL) reduction, 2log10 (CFU/mL) reduction and 3log10 (CFU/mL) reduction were 32.48, 45.68, and 54.36%, respectively, during 48 h treatment period of doxycycline. In conclusion, doxycycline shows excellent effectiveness and time-dependent characteristics against M. gallisepticum strain S6 in vitro. Additionally, these results will guide optimal dosing strategies of doxycycline in M. gallisepticum infection. PMID:27199972
-
Efficacy of on-farm use of ultraviolet light for inactivation of bacteria in milk for calves.
Gelsinger, S L; Heinrichs, A J; Jones, C M; Van Saun, R J; Wolfgang, D R; Burns, C M; Lysczek, H R
2014-05-01
Ultraviolet light is being employed for bacterial inactivation in milk for calves; however, limited evidence is available to support the claim that UV light effectively inactivates bacteria found in milk. Thus, the objective of this observational study was to investigate the efficacy of on-farm UV light treatment in reducing bacteria populations in waste milk used for feeding calves. Samples of nonsaleable milk were collected from 9 Pennsylvania herds, twice daily for 15 d, both before and after UV light treatment (n=60 samples per farm), and analyzed for standard plate count, coliforms, noncoliform, gram-negative bacteria, environmental and contagious streptococci, coagulase-negative staphylococci, Streptococcus agalactiae, Staphylococcus aureus count, and total solids percentage, and log reduction and percentage log reduction were calculated. Data were analyzed using the mixed procedure in SAS. In all bacteria types, samples collected after UV treatment contained significantly fewer bacteria compared with samples collected before UV treatment. Weighted least squares means for log reduction (percentage log reduction) were 1.34 (29%), 1.27 (58%), 1.48 (53%), 1.85 (55%), 1.37 (72%), 1.92 (63%), 1.07 (33%), and 1.67 (82%) for standard plate count, coliforms, noncoliform, gram-negative bacteria, environmental and contagious streptococci, Strep. agalactiae, coagulase-negative staphylococci, and Staph. aureus, respectively. A percentage log reduction greater than 50% was achieved in 6 of 8 bacteria types, and 43 and 94% of samples collected after UV treatment met recommended bacterial standards for milk for feeding calves. Based on these results, UV light treatment may be effective for some, but not all bacteria types found in nonsaleable waste milk. Thus, farmers should take into account the bacteria types that may need to be reduced when considering the purchase of a UV-treatment system. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
-
Antibacterial Efficacy of Several Surgical Hand Preparation Products Used by Veterinary Students.
Chou, Po-Yen; Doyle, Aimie J; Arai, Shiori; Burke, Pierre J; Bailey, Trina R
2016-05-01
To compare the antibacterial efficacy of different surgical hand antisepsis protocols used by veterinary students. Prospective, randomized, controlled study. Third year veterinary students (n=45). The participants were randomly assigned to 4 of the following 12 hand preparation product/time combinations: nonabrasive hand scrub method with 4% chlorhexidine gluconate (CH); hand rub with a mixture of 30% 1-propanol and 45% 2-propanol solution (MPS), 70% 2-propanol solution (IPS), or 61% ethanol solution with 1% chlorhexidine gluconate (ES/CH), with a contact time of 1.5, 3, or 5 minutes. Antibacterial efficacy was assessed after surgical hand preparation and at the end of surgery. Log reductions of total bacterial colony forming unit (CFU)/mL and positive aerobic culture rates were compared using multivariable analysis of variance and multivariable logistic regression, respectively. After surgical hand preparation, CH and ES/CH provided significantly higher log CFU reduction and lower positive culture rate for Gram-positive and spore-forming bacteria compared to MPS and IPS. Increase in contact time did not provide significant improvement in bacterial reduction. At the end of surgery, ES/CH provided significantly higher log CFU reduction compared to IPS and lower positive culture rate for Gram-positive bacteria compared to CH, MPS, and IPS. Increase in contact time significantly improved log CFU reduction in ES/CH and MPS groups. In our population of veterinary students ES/CH hand rubs or CH scrubs were more effective in reducing bacterial CFU during surgical hand preparation than MPS or IPS. © Copyright 2016 by The American College of Veterinary Surgeons.
-
Optimizing Unmanned Aircraft System Scheduling
2008-06-01
COL_MISSION_NAME)) If Trim( CStr (rMissions(iRow, COL_MISSION_REQUIRED))) <> "" Then If CLng(rMissions(iRow, COL_MISSION_REQUIRED)) > CLng...logFN, "s:" & CStr (s) & " " For iRow = 1 To top Print #logFN, stack(iRow) & "," Next iRow Print #logFN...340" 60 Print #logFN, "m:" & CStr (s) & " " For iRow = 1 To top Print #logFN, lMissionPeriod(iRow
-
Procedures for Geometric Data Reduction in Solid Log Modelling
Luis G. Occeña; Wenzhen Chen; Daniel L. Schmoldt
1995-01-01
One of the difficulties in solid log modelling is working with huge data sets, such as those that come from computed axial tomographic imaging. Algorithmic procedures are described in this paper that have successfully reduced data without sacrificing modelling integrity.
-
Novel denture-cleaning system based on hydroxyl radical disinfection.
Kanno, Taro; Nakamura, Keisuke; Ikai, Hiroyo; Hayashi, Eisei; Shirato, Midori; Mokudai, Takayuki; Iwasawa, Atsuo; Niwano, Yoshimi; Kohno, Masahiro; Sasaki, Keiichi
2012-01-01
The purpose of this study was to evaluate a new denture-cleaning device using hydroxyl radicals generated from photolysis of hydrogen peroxide (H2O2). Electron spin resonance analysis demonstrated that the yield of hydroxyl radicals increased with the concentration of H2O2 and light irradiation time. Staphylococcus aureus, Pseudomonas aeruginosa, and methicillin-resistant S aureus were killed within 10 minutes with a > 5-log reduction when treated with photolysis of 500 mM H2O2; Candida albicans was killed within 30 minutes with a > 4-log reduction with photolysis of 1,000 mM H2O2. The clinical test demonstrated that the device could effectively reduce microorganisms in denture plaque by approximately 7-log order within 20 minutes.
-
Parental perceptions of the learner driver log book system in two Australian states.
Bates, Lyndel; Watson, Barry; King, Mark Johann
2014-01-01
Though many jurisdictions internationally now require learner drivers to complete a specified number of hours of supervised driving practice before being able to drive unaccompanied, very few require learner drivers to complete a log book to record this practice and then present it to the licensing authority. Learner drivers in most Australian jurisdictions must complete a log book that records their practice, thereby confirming to the licensing authority that they have met the mandated hours of practice requirement. These log books facilitate the management and enforcement of minimum supervised hours of driving requirements. Parents of learner drivers in 2 Australian states, Queensland and New South Wales, completed an online survey assessing a range of factors, including their perceptions of the accuracy of their child's learner log book and the effectiveness of the log book system. The study indicates that the large majority of parents believe that their child's learner log book is accurate. However, they generally report that the log book system is only moderately effective as a system to measure the number of hours of supervised practice a learner driver has completed. The results of this study suggest the presence of a paradox, with many parents possibly believing that others are not as diligent in the use of log books as they are or that the system is too open to misuse. Given that many parents report that their child's log book is accurate, this study has important implications for the development and ongoing monitoring of hours of practice requirements in graduated driver licensing systems.
-
Chlorine Dioxide Fumigation of Subway Materials ...
Report This bench scale study observed that a six (6) log reduction in viable spores of a suitable B. anthracis surrogate can be obtained for subway infrastructure materials by ClO2 fumigation if the temperature is at or above 24 °C combined with RH greater than 75%. No six log reduction in viable spores was observed at realistic (winter) temperatures in a subway environment (11-13 °C and 70-80% RH) for periods of fumigation that are otherwise efficacious at 24 °C/ 75% RH.
-
Inactivation of Viruses and Bacteriophages as Models for Swine Hepatitis E Virus in Food Matrices.
Emmoth, Eva; Rovira, Jordi; Rajkovic, Andreja; Corcuera, Elena; Wilches Pérez, Diego; Dergel, Irene; Ottoson, Jakob R; Widén, Frederik
2017-03-01
Hepatitis E virus has been recognised as a food-borne virus hazard in pork products, due to its zoonotic properties. This risk can be reduced by adequate treatment of the food to inactivate food-borne viruses. We used a spectrum of viruses and bacteriophages to evaluate the effect of three food treatments: high pressure processing (HPP), lactic acid (LA) and intense light pulse (ILP) treatments. On swine liver at 400 MPa for 10 min, HPP gave log 10 reductions of ≥4.2, ≥5.0 and 3.4 for feline calicivirus (FCV) 2280, FCV wildtype (wt) and murine norovirus 1 (MNV 1), respectively. Escherichia coli coliphage ϕX174 displayed a lower reduction of 1.1, while Escherichia coli coliphage MS2 was unaffected. For ham at 600 MPa, the corresponding reductions were 4.1, 4.4, 2.9, 1.7 and 1.3 log 10 . LA treatment at 2.2 M gave log 10 reductions in the viral spectrum of 0.29-2.1 for swine liver and 0.87-3.1 for ham, with ϕX174 and MNV 1, respectively, as the most stable microorganisms. The ILP treatment gave log 10 reductions of 1.6-2.8 for swine liver, 0.97-2.2 for ham and 1.3-2.3 for sausage, at 15-60 J cm -2 , with MS2 as the most stable microorganism. The HPP treatment gave significantly (p < 0.05) greater virus reduction on swine liver than ham for the viruses at equivalent pressure/time combinations. For ILP treatment, reductions on swine liver were significantly (p < 0.05) greater than on ham for all microorganisms. The results presented here could be used in assessments of different strategies to protect consumers against virus contamination and in advice to food producers. Conservative model indicators for the pathogenic viruses could be suggested.
-
Permeability-porosity relationships in sedimentary rocks
Nelson, Philip H.
1994-01-01
In many consolidated sandstone and carbonate formations, plots of core data show that the logarithm of permeability (k) is often linearly proportional to porosity (??). The slope, intercept, and degree of scatter of these log(k)-?? trends vary from formation to formation, and these variations are attributed to differences in initial grain size and sorting, diagenetic history, and compaction history. In unconsolidated sands, better sorting systematically increases both permeability and porosity. In sands and sandstones, an increase in gravel and coarse grain size content causes k to increase even while decreasing ??. Diagenetic minerals in the pore space of sandstones, such as cement and some clay types, tend to decrease log(k) proportionately as ?? decreases. Models to predict permeability from porosity and other measurable rock parameters fall into three classes based on either grain, surface area, or pore dimension considerations. (Models that directly incorporate well log measurements but have no particular theoretical underpinnings from a fourth class.) Grain-based models show permeability proportional to the square of grain size times porosity raised to (roughly) the fifth power, with grain sorting as an additional parameter. Surface-area models show permeability proportional to the inverse square of pore surface area times porosity raised to (roughly) the fourth power; measures of surface area include irreducible water saturation and nuclear magnetic resonance. Pore-dimension models show permeability proportional to the square of a pore dimension times porosity raised to a power of (roughly) two and produce curves of constant pore size that transgress the linear data trends on a log(k)-?? plot. The pore dimension is obtained from mercury injection measurements and is interpreted as the pore opening size of some interconnected fraction of the pore system. The linear log(k)-?? data trends cut the curves of constant pore size from the pore-dimension models, which shows that porosity reduction is always accompanied by a reduction in characteristic pore size. The high powers of porosity of the grain-based and surface-area models are required to compensate for the inclusion of the small end of the pore size spectrum.
-
The significance of sweep in Appalachian hardwood sawlogs
Thomas W., Jr. Church
1973-01-01
Sweep is one of the major stem-form defects in hardwood sawtimber. Some sweep is removed during bucking. But we found sweep of 2 inches or more on 17 percent of the 4,510 logs measured at Appalachian sawmills. Volume deductions for sweep scaled at least 10 percent in 1 of every 7 sample logs and at least 15 percent in 1 of every 9 sample logs. Reduction in the severity...
-
AN ASSESSMENT OF MCNP WEIGHT WINDOWS
DOE Office of Scientific and Technical Information (OSTI.GOV)
J. S. HENDRICKS; C. N. CULBERTSON
2000-01-01
The weight window variance reduction method in the general-purpose Monte Carlo N-Particle radiation transport code MCNPTM has recently been rewritten. In particular, it is now possible to generate weight window importance functions on a superimposed mesh, eliminating the need to subdivide geometries for variance reduction purposes. Our assessment addresses the following questions: (1) Does the new MCNP4C treatment utilize weight windows as well as the former MCNP4B treatment? (2) Does the new MCNP4C weight window generator generate importance functions as well as MCNP4B? (3) How do superimposed mesh weight windows compare to cell-based weight windows? (4) What are the shortcomingsmore » of the new MCNP4C weight window generator? Our assessment was carried out with five neutron and photon shielding problems chosen for their demanding variance reduction requirements. The problems were an oil well logging problem, the Oak Ridge fusion shielding benchmark problem, a photon skyshine problem, an air-over-ground problem, and a sample problem for variance reduction.« less
-
Koo, Ok-Kyung; Eggleton, Mallory; O'Bryan, Corliss A; Crandall, Philip G; Ricke, Steven C
2012-12-01
Contamination by Listeria monocytogenes has been a constant public health threat for the ready-to-eat (RTE) meat industry due to the potential for high mortalities from listeriosis. Lactic acid bacteria (LAB) have shown protective action against various pathogenic bacteria. The aim of this study was to evaluate the antilisterial activity of a combination of three LAB strains (Lactiguard®) on L. monocytogenes. The combination of the LAB was inhibitory to L. monocytogenes inoculated onto frankfurters not containing lactate/diacetate after 8weeks of refrigerated storage (0.6 log reduction compared to L. monocytogenes only control), and when a cell free extract (CFS) of the LAB was added with LAB even more inhibition was obtained (1.2 log reduction compared with L. monocytogenes only). In frankfurters containing lactate/diacetate the LAB and the LAB plus CFS were more effective in reducing growth of L. monocytogenes after 8 weeks of refrigerated storage (2 and 3.3 log reductions respectively). Copyright © 2012 Elsevier Ltd. All rights reserved.
-
10 CFR 34.71 - Utilization logs.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 1 2010-01-01 2010-01-01 false Utilization logs. 34.71 Section 34.71 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Recordkeeping Requirements § 34.71 Utilization logs. (a) Each licensee shall maintain...
-
10 CFR 34.71 - Utilization logs.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 10 Energy 1 2014-01-01 2014-01-01 false Utilization logs. 34.71 Section 34.71 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Recordkeeping Requirements § 34.71 Utilization logs. (a) Each licensee shall maintain...
-
10 CFR 34.71 - Utilization logs.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 10 Energy 1 2011-01-01 2011-01-01 false Utilization logs. 34.71 Section 34.71 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Recordkeeping Requirements § 34.71 Utilization logs. (a) Each licensee shall maintain...
-
10 CFR 34.71 - Utilization logs.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 10 Energy 1 2012-01-01 2012-01-01 false Utilization logs. 34.71 Section 34.71 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Recordkeeping Requirements § 34.71 Utilization logs. (a) Each licensee shall maintain...
-
10 CFR 34.71 - Utilization logs.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 10 Energy 1 2013-01-01 2013-01-01 false Utilization logs. 34.71 Section 34.71 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Recordkeeping Requirements § 34.71 Utilization logs. (a) Each licensee shall maintain...
-
Pina-Pérez, M C; Silva-Angulo, A B; Rodrigo, D; Martínez-López, A
2009-04-15
With a view to extending the shelf-life and enhancing the safety of liquid whole egg/skim milk (LWE-SM) mixed beverages, a study was conducted with Bacillus cereus vegetative cells inoculated in skim milk (SM) and LWE-SM beverages, with or without antimicrobial cocoa powder. The beverages were treated with Pulsed Electric Field (PEF) technology and then stored at 5 degrees C for 15 days. The kinetic results were modeled with the Bigelow model, Weibull distribution function, modified Gompertz equation, and Log-logistic models. Maximum inactivation registered a reduction of around 3 log cycles at 40 kV/cm, 360 micros, 20 degrees C in both the SM and LWE-SM beverages. By contrast, in the beverages supplemented with the aforementioned antimicrobial compound, higher inactivation levels were obtained under the same treatment conditions, reaching a 3.30 log(10) cycle reduction. The model affording the best fit for all four beverages was the four-parameter Log-logistic model. After 15 days of storage, the antimicrobial compound lowered Bacillus cereus survival rates in the samples supplemented with CocoanOX 12% by a 4 log cycle reduction, as compared to the untreated samples without CocoanOX 12%. This could indicate that the PEF-antimicrobial combination has a synergistic effect on the bacterial cells under study, increasing their sensitivity to subsequent refrigerated storage.
-
Fate of Listeria monocytogenes on Fresh Apples under Different Storage Temperatures.
Sheng, Lina; Edwards, Katheryn; Tsai, Hsieh-Chin; Hanrahan, Ines; Zhu, Mei-Jun
2017-01-01
Fresh apples are typically stored for up to 1 year commercially; different apple varieties require different storage temperatures to maintain their quality characteristics. There is sparse information available about Listeria monocytogenes survival on fresh apples under various storage temperatures. The objective of this study was to comprehensively evaluate the effect of storage temperature on apple fruit decay and L. monocytogenes survival. Unwaxed apple fruits of selected varieties (Fuji and Granny Smith) were dip inoculated in a three-strain L. monocytogenes cocktail to establish ∼3.5 and 6.0 Log 10 CFU/apple. Twenty-four hours post-inoculation, apples were subjected to 1, 4, 10, or 22°C storage for up to 3 months. Apples under the different storage treatments were sampled at 1-, 4-, 7- and 14-day for short-term storage under all four tested temperatures, and 2-, 4-, 8-, and 12-week for long-term storage at 1, 4, and 10°C. A set of uninoculated and unwaxed apples were simultaneously subjected to the previously mentioned storage temperatures and sampled biweekly for their total bacterial count (TPC) and yeasts/molds (Y/M) count. During the 2-week short-term storage, L. monocytogenes population on organic Granny Smith apples stored at 1, 4, or 10°C was reduced by 0.2-0.3 Log. When apples were stored at 22°C, there was a 0.5-1.2 Log 10 CFU/apple reduction 14-day post storage dependent on the initial inoculation level. During the 12-week cold storage under 1, 4, and 10°C, L. monocytogenes count on organic Granny Smith apples decreased by 0.5-1.5 Log 10 CFU/apple for both inoculation levels. L. monocytogenes had similar survival pattern on conventional Granny Smith and Fuji apples with 0.8-2.0 Log 10 CFU/apple reduction over a 3-month cold storage period. Interestingly, both TPC and Y/M count were stable regardless of apple variety or cultivation practice during the 12-week storage at all tested temperatures. In summary, while L. monocytogenes did not proliferate on apple surfaces during 12 weeks of refrigerated storage, only a limited reduction of L. monocytogenes was observed in this study. Therefore, the apple industry cannot rely on cold storage alone to control this pathogen. Additional interventions are needed to eradicate Listeria on fresh apples during long-term cold storage.
-
Estimating air-drying times of small-diameter ponderosa pine and Douglas-fir logs
William T. Simpson; Xiping Wang
2004-01-01
One potential use for small-diameter ponderosa pine and Douglas-fir timber is in log form. Many potential uses of logs require some degree of drying. Even though these small diameters may be considered small in the forestry context, their size when compared to typical lumber thickness dimensions is large. These logs, however, may require uneconomically long kiln-drying...
-
Use of hot water for beef carcass decontamination.
Castillo, A; Lucia, L M; Goodson, K J; Savell, J W; Acuff, G R
1998-01-01
Hot water treatment of beef carcass surfaces for reduction of Escherichia coli O157:H7, Salmonella typhimurium, and various indicator organisms was studied using a model carcass spray cabinet. Paired hot carcass surface regions with different external fat characteristics (inside round, outside round, brisket, flank, and clod) were removed from carcasses immediately after the slaughter and dressing process. All cuts were inoculated with bovine feces containing 10(6)/g each of rifampicin-resistant E. coli O157:H7 and S. typhimurium, or with uninoculated bovine feces. Surfaces then were exposed to a carcass water wash or a water wash followed by hot water spray (95 degrees C). Counts of rifampicin-resistant Salmonella and E. coli or aerobic plate count (APC) and coliform counts were conducted before and after each treatment. All treatments significantly reduced levels of pathogens from the initial inoculation level of 5.0 log(10) CFU/cm2. Treatments including hot water sprays provided mean reductions of initial counts for E. coli O157:H7 and S. typhimurium of 3.7 and 3.8 log, APC reductions of 2.9 log, and coliform and thermotolerant coliform count reductions of 3.3 log. The efficacy of hot water treatments was affected by the carcass surface region, but not by delaying the treatment (30 min) after contaminating the surface. Verification of efficacy of hot water interventions used as critical control points in a hazard analysis critical control point (HACCP) system may be possible using coliform counts.
-
Blaschke, A. P.; Toze, S.; Sidhu, J. P. S.; Ahmed, W.; van Driezum, I. H.; Sommer, R.; Kirschner, A. K. T.; Cervero-Aragó, S.; Farnleitner, A. H.; Pang, L.
2015-01-01
Members of the genus Cryptosporidium are waterborne protozoa of great health concern. Many studies have attempted to find appropriate surrogates for assessing Cryptosporidium filtration removal in porous media. In this study, we evaluated the filtration of Cryptosporidium parvum in granular limestone medium by the use of biotin- and glycoprotein-coated carboxylated polystyrene microspheres (CPMs) as surrogates. Column experiments were carried out with core material taken from a managed aquifer recharge site in Adelaide, Australia. For the experiments with injection of a single type of particle, we observed the total removal of the oocysts and glycoprotein-coated CPMs, a 4.6- to 6.3-log10 reduction of biotin-coated CPMs, and a 2.6-log10 reduction of unmodified CPMs. When two different types of particles were simultaneously injected, glycoprotein-coated CPMs showed a 5.3-log10 reduction, while the uncoated CPMs displayed a 3.7-log10 reduction, probably due to particle-particle interactions. Our results confirm that glycoprotein-coated CPMs are the most accurate surrogates for C. parvum; biotin-coated CPMs are slightly more conservative, while unmodified CPMs are markedly overly conservative for predicting C. parvum removal in granular limestone medium. The total removal of C. parvum observed in our study suggests that granular limestone medium is very effective for the filtration removal of C. parvum and could potentially be used for the pretreatment of drinking water and aquifer storage recovery of recycled water. PMID:25888174
-
Han, Bok Kung; Choi, Hyuk Joon; Kang, Shin Ho; Baick, Seung Chun
2015-01-01
We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 μs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorganisms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (p<0.05). These results indicate that a relatively low electric-field strength of 10 kV/cm can be used to pasteurize low-fat milk. PMID:26877640
-
Lee, Gun Joon; Han, Bok Kung; Choi, Hyuk Joon; Kang, Shin Ho; Baick, Seung Chun; Lee, Dong-Un
2015-01-01
We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 μs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorganisms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (p<0.05). These results indicate that a relatively low electric-field strength of 10 kV/cm can be used to pasteurize low-fat milk.
-
Larson, Elaine L; Cohen, Bevin; Baxter, Kathleen A
2012-11-01
Minimal research has been published evaluating the effectiveness of hand hygiene delivery systems (ie, rubs, foams, or wipes) at removing viruses from hands. The purposes of this study were to determine the effect of several alcohol-based hand sanitizers in removing influenza A (H1N1) virus, and to compare the effectiveness of foam, gel, and hand wipe products. Hands of 30 volunteers were inoculated with H1N1 and randomized to treatment with foam, gel, or hand wipe applied to half of each volunteer's finger pads. The log(10) count of each subject's treated and untreated finger pads were averaged. Log(10) reductions were calculated from these differences and averaged within treatment group. Between-treatment analysis compared changes from the untreated finger pads using analysis of covariance with treatment as a factor and the average log(10) untreated finger pads as the covariate. Log(10) counts on control finger pads were 2.7-5.3 log(10) of the 50% infectious dose for tissue culture (TCID(50)/0.1 mL) (mean, 3.8 ± 0.5 log(10) TCID(50)/0.1 mL), and treated finger pad counts for all test products were 0.5-1.9 log(10) TCID(50)/0.1 mL (mean, 0.53 ± 0.17 log(10) TCID(50)/0.1 mL). Treatments with all products resulted in a significant reduction in viral titers (>3 logs) at their respective exposure times that were statistically comparable. All 3 delivery systems (foam, gel, and wipe) produced significantly reduced viral counts on hands. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.
-
NASA Astrophysics Data System (ADS)
Koval'ová, Zuzana; Tarabová, Kataŕna; Hensel, Karol; Machala, Zdenko
2013-02-01
Cold air plasmas of DC and pulsed corona discharges: positive streamers and negative Trichel pulses were used for bio-decontamination of Streptococci biofilm and Bacillus cereus spores on polypropylene plastic surfaces. The reduction of bacterial population (evaluated as log10) in the biofilm on plastic surfaces treated by DC corona reached 2.4 logs with 10 min treatment time and 3.3 logs with 2 min treatment time with water spraying. The enhancement of plasma biocidal effects on the biofilm by electro-spraying of water through a hollow needle high-voltage electrode was investigated. No significant polarity effect was found with DC corona. Pulsed corona was demonstrated slightly more bactericidal for spores, especially in the negative polarity where the bacterial population reduction reached up to 2.2 logs at 10 min exposure time. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.
-
Disinfection of Spacecraft Potable Water Systems by Passivation with Ionic Silver
NASA Technical Reports Server (NTRS)
Birmele, Michele N.; McCoy, LaShelle e.; Roberts, Michael S.
2011-01-01
Microbial growth is common on wetted surfaces in spacecraft environmental control and life support systems despite the use of chemical and physical disinfection methods. Advanced control technologies are needed to limit microorganisms and increase the reliability of life support systems required for long-duration human missions. Silver ions and compounds are widely used as antimicrobial agents for medical applications and continue to be used as a residual biocide in some spacecraft water systems. The National Aeronautics and Space Administration (NASA) has identified silver fluoride for use in the potable water system on the next generation spacecraft. Due to ionic interactions between silver fluoride in solution and wetted metallic surfaces, ionic silver is rapidly depleted from solution and loses its antimicrobial efficacy over time. This report describes research to prolong the antimicrobial efficacy of ionic silver by maintaining its solubility. Three types of metal coupons (lnconel 718, Stainless Steel 316, and Titanium 6AI-4V) used in spacecraft potable water systems were exposed to either a continuous flow of water amended with 0.4 mg/L ionic silver fluoride or to a static, pre-treatment passivation in 50 mg/L ionic silver fluoride with or without a surface oxidation pre-treatment. Coupons were then challenged in a high-shear, CDC bioreactor (BioSurface Technologies) by exposure to six bacteria previously isolated from spacecraft potable water systems. Continuous exposure to 0.4 mg/L ionic silver over the course of 24 hours during the flow phase resulted in a >7-log reduction. The residual effect of a 24-hour passivation treatment in 50 mg/L of ionic silver resulted in a >3-log reduction, whereas a two-week treatment resulted in a >4-log reduction. Results indicate that 0.4 mg/L ionic silver is an effective biocide against many bacteria and that a prepassivation of metal surfaces with silver can provide additional microbial control.
-
Kato, Ryuichi; Asami, Tatsuya; Utagawa, Etsuko; Furumai, Hiroaki; Katayama, Hiroyuki
2018-04-01
To assess the potential of pepper mild mottle virus (PMMoV) as a viral process indicator, its reduction through coagulation-sedimentation (CS) and rapid sand filtration (RSF) were compared with those of Escherichia coli, previously used viral indicators, and norovirus genotype II (NoV GII; enteric virus reference pathogen) in a bench-scale experiment. PMMoV log 10 reductions in CS (1.96 ± 0.30) and RSF (0.26 ± 0.38) were similar to those of NoV GII (1.86 ± 0.61 and 0.28 ± 0.46). PMMoV, the most abundant viruses in the raw water, was also determined during CS, RSF, and advanced treatment processes at two full-scale drinking water treatment plants under strict turbidity management over a 13-month period. PMMoV was concentrated from large-volume water samples (10-614 L) and quantified by Taqman-based quantitative polymerase chain reaction. The PMMoV log 10 reduction in CS (2.38 ± 0.74, n = 13 and 2.63 ± 0.76, n = 10 each for Plant A and B) and in ozonation (1.91 ± 1.18, n = 5, Plant A) greatly contributed to the overall log 10 reduction. Our results suggest that PMMoV can act as a useful treatment process indicator of enteric viruses and can be used to monitor the log 10 reduction of individual treatment processes at drinking water treatment plants due to its high and consistent copy numbers in source water. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
Peracetic acid (PAA) disinfection of primary, secondary and tertiary treated municipal wastewaters.
Koivunen, J; Heinonen-Tanski, H
2005-11-01
The efficiency of peracetic acid (PAA) disinfection against enteric bacteria and viruses in municipal wastewaters was studied in pilot-scale. Disinfection pilot-plant was fed with the primary or secondary effluent of Kuopio municipal wastewater treatment plant or tertiary effluent from the pilot-scale dissolved air flotation (DAF) unit. Disinfectant doses ranged from 2 to 7 mg/l PAA in the secondary and tertiary effluents, and from 5 to 15 mg/l PAA in the primary effluents. Disinfection contact times were 4-27 min. Disinfection of secondary and tertiary effluents with 2-7 mg/l PAA and 27 min contact time achieved around 3 log reductions of total coliforms (TC) and enterococci (EC). PAA disinfection also significantly improved the hygienic quality of the primary effluents: 10-15 mg/l PAA achieved 3-4 log reductions of TC and EC, 5 mg/l PAA resulting in below 2 log reductions. F-RNA coliphages were more resistant against the PAA disinfection and around 1 log reductions of these enteric viruses were typically achieved in the disinfection treatments of the primary, secondary and tertiary effluents. Most of the microbial reductions occurred during the first 4-18 min of contact time, depending on the PAA dose and microorganism. The PAA disinfection efficiency remained relatively constant in the secondary and tertiary effluents, despite of small changes of wastewater quality (COD, SS, turbidity, 253.7 nm transmittance) or temperature. The disinfection efficiency clearly decreased in the primary effluents with substantially higher microbial, organic matter and suspended solids concentrations. The results demonstrated that PAA could be a good alternative disinfection method for elimination of enteric microbes from different wastewaters.
-
Predmore, Ashley; Li, Jianrong
2011-01-01
Fruits and vegetables are major vehicles for transmission of food-borne enteric viruses since they are easily contaminated at pre- and postharvest stages and they undergo little or no processing. However, commonly used sanitizers are relatively ineffective for removing human norovirus surrogates from fresh produce. In this study, we systematically evaluated the effectiveness of surfactants on removal of a human norovirus surrogate, murine norovirus 1 (MNV-1), from fresh produce. We showed that a panel of surfactants, including sodium dodecyl sulfate (SDS), Nonidet P-40 (NP-40), Triton X-100, and polysorbates, significantly enhanced the removal of viruses from fresh fruits and vegetables. While tap water alone and chlorine solution (200 ppm) gave only <1.2-log reductions in virus titer in all fresh produce, a solution containing 50 ppm of surfactant was able to achieve a 3-log reduction in virus titer in strawberries and an approximately 2-log reduction in virus titer in lettuce, cabbage, and raspberries. Moreover, a reduction of approximately 3 logs was observed in all the tested fresh produce after sanitization with a solution containing a combination of 50 ppm of each surfactant and 200 ppm of chlorine. Taken together, our results demonstrate that the combination of a surfactant with a commonly used sanitizer enhanced the efficiency in removing viruses from fresh produce by approximately 100 times. Since SDS is an FDA-approved food additive and polysorbates are recognized by the FDA as GRAS (generally recognized as safe) products, implementation of this novel sanitization strategy would be a feasible approach for efficient reduction of the virus load in fresh produce. PMID:21622782
-
Buchholz, A; Matthews, K R
2010-10-01
The efficacy of a commercial seed washer and 1 and 3% peroxyacetic acid or 20 000 ppm calcium hypochlorite for reducing Salmonella on alfalfa seeds was investigated. Alfalfa seeds were inoculated with Salmonella Stanley to achieve c. 5 log CFU g(-1). Seeds were then treated with 1 or 3% peroxyacetic acid or 20 000 ppm calcium hypochlorite for 15 min in a commercial seed washer that uses air to enhance contact of the sanitizer with the seed. Experiments were also conducted using industry and laboratory methods. An c. 1-log reduction in number of Salm. Stanley was demonstrated regardless of the chemical treatment or method of treatment. Although this 1-log reduction was significant (P < 0.05), differences among the treatments were not significant. Treating the seed with 1 and 3% peroxyacetic acid resulted in similar Salm. Stanley reductions of 1.77 and 1.34 log, respectively, not being statistically significant (P > 0.05). These results suggest that under conditions tested, 1 or 3% peroxyacetic acid solutions are equally effective as 20 000 ppm of Ca(OCl)2 in the reduction of Salm. Stanley on alfalfa seed when used in conjunction with a commercial seed washer. A 1% peroxyacetic acid solution could potentially be used in place of 20 000 ppm of Ca(OCl)2 for treatment of seeds used for sprouting. The commercial seed washer did not enhance removal of Salm. Stanley from alfalfa seeds, but did facilitate removal of excess soil from seeds. © 2010 The Authors. Journal compilation © 2010 The Society for Applied Microbiology.
-
Edward H. Holsten; Richard A. Werner
1993-01-01
Covering stacks of spruce firewood with either clear or black polyethylene sheeting does not raise log temperatures high enough to kill spruce beetle brood in the logs. Based on the results of this study, we do not recommend the use of polyethylene sheeting as a remedial measure for the reduction of spruce beetle brood in infested firewood or log decks in south-central...
-
46 CFR 148.100 - Log book entries.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 46 Shipping 5 2012-10-01 2012-10-01 false Log book entries. 148.100 Section 148.100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Minimum Transportation Requirements § 148.100 Log book entries. During...
-
46 CFR 148.100 - Log book entries.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 46 Shipping 5 2011-10-01 2011-10-01 false Log book entries. 148.100 Section 148.100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Minimum Transportation Requirements § 148.100 Log book entries. During...
-
46 CFR 148.100 - Log book entries.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 5 2014-10-01 2014-10-01 false Log book entries. 148.100 Section 148.100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Minimum Transportation Requirements § 148.100 Log book entries. During...
-
46 CFR 148.100 - Log book entries.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 46 Shipping 5 2013-10-01 2013-10-01 false Log book entries. 148.100 Section 148.100 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Minimum Transportation Requirements § 148.100 Log book entries. During...
-
Biocontrol of Escherichia coli O157: H7 on fresh-cut leafy greens.
Boyacioglu, Olcay; Sharma, Manan; Sulakvelidze, Alexander; Goktepe, Ipek
2013-01-01
The effect of a bacteriophage cocktail (EcoShield™) that is specific against Escherichia coli O157:H7 was evaluated against a nalidixic acid-resistant enterohemorrhagic E. coli O157:H7 RM4407 (EHEC) strain on leafy greens stored under either (1) ambient air or (2) modified atmosphere (MA; 5% O 2 /35% CO 2 /60% N 2 ). Pieces (~2 × 2 cm 2 ) of leafy greens (lettuce and spinach) inoculated with 4.5 log CFU/cm 2 EHEC were sprayed with EcoShield™ (6.5 log PFU/cm 2 ). Samples were stored at 4 or 10°C for up to 15 d. On spinach, the level of EHEC declined by 2.38 and 2.49 log CFU/cm 2 at 4 and 10°C, respectively, 30 min after phage application (p ≤ 0.05). EcoShield™ was also effective in reducing EHEC on the surface of green leaf lettuce stored at 4°C by 2.49 and 3.28 log units in 30 min and 2 h, respectively (p ≤ 0.05). At 4°C under atmospheric air, the phage cocktail significantly (p ≤ 0.05) lowered the EHEC counts in one day by 1.19, 3.21 and 3.25 log CFU/cm 2 on spinach, green leaf and romaine lettuce, respectively compared with control (no bacteriophage) treatments. When stored under MA at 4°C, phages reduced (p ≤ 0.05) EHEC populations by 2.18, 3.50 and 3.13 log CFU/cm 2 , on spinach, green leaf and romaine lettuce. At 10°C, EHEC reductions under atmospheric air storage were 1.99, 3.90 and 3.99 log CFU/cm 2 (p ≤ 0.05), while population reductions under MA were 3.08, 3.89 and 4.34 logs on spinach, green leaf and romaine lettuce, respectively, compared with controls (p ≤ 0.05). The results of this study showed that bacteriophages were effective in reducing the levels of E. coli O157:H7 on fresh leafy produce, and that the reduction was further improved when produce was stored under the MA conditions.
-
McReynolds, J; Kubena, L; Byrd, J; Anderson, R; Ricke, S; Nisbet, D
2005-08-01
The method most commonly used to induce molting and stimulate multiple egg-laying cycles in laying hens for commercial egg production is to fast the hens. Unfortunately, increased risk of Salmonella enteritidis (SE) infection may result from the use of this method. Methods to stimulate multiple egg-laying cycles without increasing the risk of SE infection are needed. Hens over 50 wk of age were divided into 12 groups of 11 hens each and placed in individual laying cages. One week prior to dietary changes, hens were placed on an 8-h light and 16-h dark photoperiod that continued for the 9-d molt. All hens were challenged orally with 10(6) cfu of SE on the fourth day of the molt. Treatments were nonfed hens with distilled water (NFD), nonfed hens with the experimental chlorate product (ECP, which provided 15 mM chlorate ion) water (NFECP), alfalfa diets with distilled water (ALD), and alfalfa diets with ECP water (ALECP). In the NFD hens, 67% (log10 2.74) of the crops and 94% (log10 5.62) of the ceca were colonized, whereas for the NFECP hens significant reductions to 22% (log10 1.05) of the crops and 61% (log10 2.44) of the ceca were observed. In the ALD hens, 61% (log10 2.52) of the crops and 94% (log10 4.06) of the ceca were colonized. In the ALECP hens, highly significant reductions to 11% (log10 1.26) of the crops and 39% (log10 1.12) of the ceca were observed. When compared with the NFD hens, significant reductions in SE invasion of the ovary, liver, and spleen occurred in all other treatments, except the ovary in the ALD hens. The low alfalfa intake is probably a factor in our lowered protection against SE when compared with previous results. For several parameters, these results suggest that ECP or the combination of ECP and alfalfa may be a useful tool to reduce the risk of SE during an induced molt.
-
NASA Astrophysics Data System (ADS)
Sokołowska, Barbara; Skąpska, Sylwia; Niezgoda, Jolanta; Rutkowska, Małgorzata; Dekowska, Agnieszka; Rzoska, Sylwester J.
2014-01-01
Cells exposed to different physical and chemical treatments, including high hydrostatic pressure (HHP), suffer from injuries that could be reversible in food materials when stored. Escherichia coli and Listeria innocua cells suspended in phosphate-buffered saline (PBS) (model suspensions), and acidified beetroot juice were subjected to a pressure of 400 MPa at a temperature of 20°C for up to 10 min. The difference between the viable and non-injured cells was used to estimate the number of injured survivors. The reduction in E. coli cell number was 3.4-4.1 log after 10 min pressurization in model suspensions and 6.2 log in beetroot juice. Sublethally injured cells in PBS accounted for up to 2.7 log after 10 min HHP treatment and 0.8 log in beetroot juice. The reduction in L. innocua cell number after 10 min pressure treatment reached from 3.8 to 4.8 log, depending on the initial concentration in model suspensions. Among the surviving L. innocua cells, even up to 100% were injured. L. innocua cells were completely inactivated after 1 min HHP treatment in beetroot juice.
-
Control of Listeria monocytogenes growth in soft cheeses by bacteriophage P100.
Silva, Elaine Nóbrega Gibson; Figueiredo, Ana Cláudia Leite; Miranda, Fernanda Araújo; de Castro Almeida, Rogeria Comastri
2014-01-01
The purpose of this study was to determine the effect of bacteriophage P100 on strains of Listeria monocytogenes in artificially inoculated soft cheeses. A mix of L. monocytogenes 1/2a and Scott A was inoculated in Minas Frescal and Coalho cheeses (approximately 10(5) cfu/g) with the bacteriophage added thereafter (8.3 × 10(7) PFU/g). Samples were analyzed immediately, and then stored at 10 °C for seven days. At time zero, 30 min post-infection, the bacteriophage P100 reduced L. monocytogenes counts by 2.3 log units in Minas Frescal cheese and by 2.1 log units in Coalho cheese, compared to controls without bacteriophage. However, in samples stored under refrigeration for seven days, the bacteriophage P100 was only weakly antilisterial, with the lowest decimal reduction (DR) for the cheeses: 1.0 log unit for Minas Frescal and 0.8 log units for Coalho cheese. The treatment produced a statistically significant decrease in the counts of viable cells (p < 0.05) and in all assays performed, we observed an increase of approximately one log cycle in the number of viable cells of L. monocytogenes in the samples under refrigeration for seven days. Moreover, a smaller effect of phages was observed. These results, along with other published data, indicate that the effectiveness of the phage treatment depends on the initial concentration of L. monocytogenes, and that a high concentration of phages per unit area is required to ensure sustained inactivation of target pathogens on food surfaces.
-
Reduction of Campylobacter jejuni on chicken wings by chemical treatments.
Zhao, Tong; Doyle, Michael P
2006-04-01
Eight chemicals, including glycerol monolaurate, hydrogen peroxide, acetic acid, lactic acid, sodium benzoate, sodium chlorate, sodium carbonate, and sodium hydroxide, were tested individually or in combination for their ability to inactivate Campylobacter jejuni at 4 degrees C in suspension. Results showed that treatment for up to 20 min with 0.01% glycerol monolaurate, 0.1% sodium benzoate, 50 or 100 mM sodium chlorate, or 1% lactic acid did not substantially (< or = 0.5 log CFU/ml) reduce C. jejuni populations but that 0.1 and 0.2% hydrogen peroxide for 20 min reduced C. jejuni populations by ca. 2.0 and 4.5 log CFU/ml, respectively. By contrast, treatments with 0.5, 1.0, 1.5, and 2.0% acetic acid, 25, 50, and 100 mM sodium carbonate, and 0.05 and 0.1 N sodium hydroxide reduced C. jejuni populations by >5 log CFU/ml within 2 min. A combination of 0.5% acetic acid plus 0.05% potassium sorbate or 0.5% acetic acid plus 0.05% sodium benzoate reduced C. jejuni populations by >5 log CFU/ml within 1 min; however, substituting 0.5% lactic acid for 0.5% acetic acid was not effective, with a reduction of C. jejuni of <0.5 log CFU/ml. A combination of acidic calcium sulfate, lactic acid, ethanol, sodium dodecyl sulfate, and polypropylene glycol (ACS-LA) also reduced C. jejuni in suspension by >5 log CFU/ml within 1 min. All chemicals or chemical combinations for which there was a >5-log/ml reduction of C. jejuni in suspension were further evaluated for C. jejuni inactivation on chicken wings. Treatments at 4 degrees C of 2% acetic acid, 100 mM sodium carbonate, or 0.1 N sodium hydroxide for up to 45 s reduced C. jejuni populations by ca. 1.4, 1.6, or 3.5 log CFU/g, respectively. Treatment with ACS-LA at 4 degrees C for 15 s reduced C. jejuni by >5 log CFU/g to an undetectable level. The ACS-LA treatment was highly effective in chilled water at killing C. jejuni on chicken and, if recycled, may be a useful treatment in chill water tanks for poultry processors to reduce campylobacters on poultry skin after slaughter.
-
Rastogi, Vipin K.; Ryan, Shawn P.; Wallace, Lalena; Smith, Lisa S.; Shah, Saumil S.; Martin, G. Blair
2010-01-01
Efficacy of chlorine dioxide (CD) gas generated by two distinct generation systems, Sabre (wet system with gas generated in water) and ClorDiSys (dry system with gas generated in air), was evaluated for inactivation of Bacillus anthracis spores on six building interior surfaces. The six building materials included carpet, acoustic ceiling tile, unpainted cinder block, painted I-beam steel, painted wallboard, and unpainted pinewood. There was no statistically significant difference in the data due to the CD generation technology at a 95% confidence level. Note that a common method of CD gas measurement was used for both wet and dry CD generation types. Doses generated by combinations of different concentrations of CD gas (500, 1,000, 1,500, or 3,000 parts per million of volume [ppmv]) and exposure times (ranging between 0.5 and 12 h) were used to evaluate the relative role of fumigant exposure period and total dose in the decontamination of building surfaces. The results showed that the time required to achieve at least a 6-log reduction in viable spores is clearly a function of the material type on which the spores are inoculated. The wood and cinder block coupons required a longer exposure time to achieve a 6-log reduction. The only material showing a clear statistical difference in rate of decay of viable spores as a function of concentration was cinder block. For all other materials, the profile of spore kill (i.e., change in number of viable spores with exposure time) was not dependent upon fumigant concentration (500 to 3,000 ppmv). The CD dose required for complete spore kill on biological indicators (typically, 1E6 spores of Bacillus atrophaeus on stainless steel) was significantly less than that required for decontamination of most of the building materials tested. PMID:20305025
-
Rastogi, Vipin K; Ryan, Shawn P; Wallace, Lalena; Smith, Lisa S; Shah, Saumil S; Martin, G Blair
2010-05-01
Efficacy of chlorine dioxide (CD) gas generated by two distinct generation systems, Sabre (wet system with gas generated in water) and ClorDiSys (dry system with gas generated in air), was evaluated for inactivation of Bacillus anthracis spores on six building interior surfaces. The six building materials included carpet, acoustic ceiling tile, unpainted cinder block, painted I-beam steel, painted wallboard, and unpainted pinewood. There was no statistically significant difference in the data due to the CD generation technology at a 95% confidence level. Note that a common method of CD gas measurement was used for both wet and dry CD generation types. Doses generated by combinations of different concentrations of CD gas (500, 1,000, 1,500, or 3,000 parts per million of volume [ppmv]) and exposure times (ranging between 0.5 and 12 h) were used to evaluate the relative role of fumigant exposure period and total dose in the decontamination of building surfaces. The results showed that the time required to achieve at least a 6-log reduction in viable spores is clearly a function of the material type on which the spores are inoculated. The wood and cinder block coupons required a longer exposure time to achieve a 6-log reduction. The only material showing a clear statistical difference in rate of decay of viable spores as a function of concentration was cinder block. For all other materials, the profile of spore kill (i.e., change in number of viable spores with exposure time) was not dependent upon fumigant concentration (500 to 3,000 ppmv). The CD dose required for complete spore kill on biological indicators (typically, 1E6 spores of Bacillus atrophaeus on stainless steel) was significantly less than that required for decontamination of most of the building materials tested.
-
Live-sawing: a way to increase lumber grade yield and mill profits
Neil K. Huyler
1974-01-01
A study to compare live-sawing with conventional grade-sawing of factory-grade 3 red oak sawlogs revealed that live-sawing results in substantial increases in production rate, overrun, log value per thousand board feet, and significant reduction in size of the breakeven log diameter.
-
How much reduction of virus is needed for recycled water: A continuous changing need for assessment?
Gerba, Charles P; Betancourt, Walter Q; Kitajima, Masaaki
2017-01-01
To ensure the safety of wastewater reuse for irrigation of food crops and drinking water pathogenic viruses must be reduced to levels that pose no significant risk. To achieve this goal minimum reduction of viruses by treatment trains have been suggested. For use of edible crops a 6-log reduction and for production of potable drinking water a 12-log reduction has been suggested. These reductions were based on assuming infective virus concentrations of 10 5 to 10 6 per liter. Recent application of molecular methods suggests that some pathogenic viruses may be occurring in concentrations of 10 7 to 10 9 per liter. Factors influencing these levels include the development of molecular methods for virus detection, emergence of newly recognized viruses, decrease in per capita water use due to conservation measures, and outbreaks. Since neither cell culture nor molecular methods can assess all the potentially infectious virus in wastewater conservative estimates should be used to assess the virus load in untreated wastewater. This review indicates that an additional 2- to 3-log reduction of viruses above current recommendations may be needed to ensure the safety of recycled water. Information is needed on peak loading of viruses. In addition, more virus groups need to be quantified using better methods of virus quantification, including more accurate methods for measuring viral infectivity in order to better quantify risks from viruses in recycled water. Copyright © 2016 Elsevier Ltd. All rights reserved.
-
Balsat, Marie; Renneville, Aline; Thomas, Xavier; de Botton, Stéphane; Caillot, Denis; Marceau, Alice; Lemasle, Emilie; Marolleau, Jean-Pierre; Nibourel, Olivier; Berthon, Céline; Raffoux, Emmanuel; Pigneux, Arnaud; Rodriguez, Céline; Vey, Norbert; Cayuela, Jean-Michel; Hayette, Sandrine; Braun, Thorsten; Coudé, Marie Magdeleine; Terre, Christine; Celli-Lebras, Karine; Dombret, Hervé; Preudhomme, Claude; Boissel, Nicolas
2017-01-10
Purpose This study assessed the prognostic impact of postinduction NPM1-mutated ( NPM1m) minimal residual disease (MRD) in young adult patients (age, 18 to 60 years) with acute myeloid leukemia, and addressed the question of whether NPM1m MRD may be used as a predictive factor of allogeneic stem cell transplantation (ASCT) benefit. Patients and Methods Among 229 patients with NPM1m who were treated in the Acute Leukemia French Association 0702 (ALFA-0702) trial, MRD evaluation was available in 152 patients in first remission. Patients with nonfavorable AML according to the European LeukemiaNet (ELN) classification were eligible for ASCT in first remission. Results After induction therapy, patients who did not achieve a 4-log reduction in NPM1m peripheral blood-MRD (PB-MRD) had a higher cumulative incidence of relapse (subhazard ratio [SHR], 5.83; P < .001) and a shorter overall survival (OS; hazard ratio [HR], 10.99; P < .001). In multivariable analysis, an abnormal karyotype, the presence of FLT3-internal tandem duplication (ITD), and a < 4-log reduction in PB-MRD were significantly associated with a higher relapse incidence and shorter OS. In the subset of patients with FLT3-ITD, only age, white blood cell count, and < 4-log reduction in PB-MRD, but not FLT3-ITD allelic ratio, remained of significant prognostic value. In these patients with nonfavorable AML according to European LeukemiaNet, disease-free survival and OS were significantly improved by ASCT in those with a < 4-log reduction in PB-MRD. This benefit was not observed in those with a > 4-log reduction in PB-MRD, with a significant interaction between ASCT effect and PB-MRD response ( P = .024 and .027 for disease-free survival and OS, respectively). Conclusion Our study supports the strong prognostic significance of early NPM1m PB-MRD, independent of the cytogenetic and molecular context. Moreover, NPM1m PB-MRD may be used as a predictive factor for ASCT indication.
-
Zhao, Dongjun; Barrientos, Jessie Usaga; Wang, Qing; Markland, Sarah M; Churey, John J; Padilla-Zakour, Olga I; Worobo, Randy W; Kniel, Kalmia E; Moraru, Carmen I
2015-04-01
Thermal pasteurization can achieve the U. S. Food and Drug Administration-required 5-log reduction of pathogenic Escherichia coli O157:H7 and Cryptosporidium parvum in apple juice and cider, but it can also negatively affect the nutritional and organoleptic properties of the treated products. In addition, thermal pasteurization is only marginally effective against the acidophilic, thermophilic, and spore-forming bacteria Alicyclobacillus spp., which is known to cause off-flavors in juice products. In this study, the efficiency of a combined microfiltration (MF) and UV process as a nonthermal treatment for the reduction of pathogenic and nonpathogenic E. coli, C. parvum, and Alicyclobacillus acidoterrestris from apple cider was investigated. MF was used to physically remove suspended solids and microorganisms from apple cider, thus enhancing the effectiveness of UV and allowing a lower UV dose to be used. MF, with ceramic membranes (pore sizes, 0.8 and 1.4 μm), was performed at a temperature of 10 °C and a transmembrane pressure of 155 kPa. The subsequent UV treatment was conducted using at a low UV dose of 1.75 mJ/cm(2). The combined MF and UV achieved more than a 5-log reduction of E. coli, C. parvum, and A. acidoterrestris. MF with the 0.8-μm pore size performed better than the 1.4-μm pore size on removal of E. coli and A. acidoterrestris. The developed nonthermal hurdle treatment has the potential to significantly reduce pathogens, as well as spores, yeasts, molds, and protozoa in apple cider, and thus help juice processors improve the safety and quality of their products.
-
47 CFR 73.1840 - Retention of logs.
Code of Federal Regulations, 2014 CFR
2014-10-01
... suits upon such claims. (b) Logs may be retained on microfilm, microfiche or other data-storage systems... of logs, stored on data-storage systems, to full-size copies, is required of licensees if requested... converting to a data-storage system pursuant to the requirements of § 73.1800 (c) and (d), (§ 73.1800...
-
47 CFR 73.1840 - Retention of logs.
Code of Federal Regulations, 2013 CFR
2013-10-01
... suits upon such claims. (b) Logs may be retained on microfilm, microfiche or other data-storage systems... of logs, stored on data-storage systems, to full-size copies, is required of licensees if requested... converting to a data-storage system pursuant to the requirements of § 73.1800 (c) and (d), (§ 73.1800...
-
47 CFR 73.1840 - Retention of logs.
Code of Federal Regulations, 2011 CFR
2011-10-01
... suits upon such claims. (b) Logs may be retained on microfilm, microfiche or other data-storage systems... of logs, stored on data-storage systems, to full-size copies, is required of licensees if requested... converting to a data-storage system pursuant to the requirements of § 73.1800 (c) and (d), (§ 73.1800...
-
47 CFR 73.1840 - Retention of logs.
Code of Federal Regulations, 2012 CFR
2012-10-01
... suits upon such claims. (b) Logs may be retained on microfilm, microfiche or other data-storage systems... of logs, stored on data-storage systems, to full-size copies, is required of licensees if requested... converting to a data-storage system pursuant to the requirements of § 73.1800 (c) and (d), (§ 73.1800...
-
47 CFR 73.1840 - Retention of logs.
Code of Federal Regulations, 2010 CFR
2010-10-01
... suits upon such claims. (b) Logs may be retained on microfilm, microfiche or other data-storage systems... of logs, stored on data-storage systems, to full-size copies, is required of licensees if requested... converting to a data-storage system pursuant to the requirements of § 73.1800 (c) and (d), (§ 73.1800...
-
Veasey, Shawnna; Muriana, Peter M.
2016-01-01
‘Electrolyzed water’ generators are readily available in the food industry as a renewable source of hypochlorous acid that eliminates the need for workers to handle hazardous hypochlorite concentrates. We applied electrolyzed water (EW) directly to multi-strain cocktails of Listeria monocytogenes, E. coli O157:H7, and Salmonella sp. at 250 ppm free available chlorine (FAC) and achieved greater than 6-log reductions in 2 min. Lower EW values were examined as antimicrobial interventions for fresh meat (beef carcasses), processed meats (frankfurters), and food contact surfaces (slicing blades). Little or no reduction relative to controls was observed when generic E. coli-inoculated beef carcasses or L. monocytogenes-inoculated frankfurters were showered with EW. Spray application of EW (25 and 250-ppm FAC) onto L. monocytogenes-inoculated slicing blades showed that greater reductions were obtained with ‘clean’ (3.6 and 5.7-log reduction) vs. ‘dirty’ (0.6 and 3.3-log reduction) slicing blades, respectively. Trials with L. monocytogenes-inoculated protein-EW solutions demonstrated that protein content as low as 0.1% is capable of eliminating FAC, reducing antimicrobial activity against L. monocytogenes. EW appears better positioned as a surface sanitizer with minimal organic material that can otherwise act as an effective reducing agent to the oxidizing solution rendering it ineffective. PMID:28231137
-
Sokolova, Ekaterina; Petterson, Susan R; Dienus, Olaf; Nyström, Fredrik; Lindgren, Per-Eric; Pettersson, Thomas J R
2015-09-01
Norovirus contamination of drinking water sources is an important cause of waterborne disease outbreaks. Knowledge on pathogen concentrations in source water is needed to assess the ability of a drinking water treatment plant (DWTP) to provide safe drinking water. However, pathogen enumeration in source water samples is often not sufficient to describe the source water quality. In this study, the norovirus concentrations were characterised at the contamination source, i.e. in sewage discharges. Then, the transport of norovirus within the water source (the river Göta älv in Sweden) under different loading conditions was simulated using a hydrodynamic model. Based on the estimated concentrations in source water, the required reduction of norovirus at the DWTP was calculated using quantitative microbial risk assessment (QMRA). The required reduction was compared with the estimated treatment performance at the DWTP. The average estimated concentration in source water varied between 4.8×10(2) and 7.5×10(3) genome equivalents L(-1); and the average required reduction by treatment was between 7.6 and 8.8 Log10. The treatment performance at the DWTP was estimated to be adequate to deal with all tested loading conditions, but was heavily dependent on chlorine disinfection, with the risk of poor reduction by conventional treatment and slow sand filtration. To our knowledge, this is the first article to employ discharge-based QMRA, combined with hydrodynamic modelling, in the context of drinking water. Copyright © 2015 Elsevier B.V. All rights reserved.
-
Survival of Listeria monocytogenes in vanilla-flavored soy and dairy products stored at 8 degrees C.
Tipparaju, Sireesha; Ravishankar, Sadhana; Slade, Peter J
2004-02-01
The survival of Listeria monocytogenes V37 in vanilla-flavored yogurt (low-fat and nonfat) and soy milk (low-fat and Plus) stored at 8 degrees C for 31 days was investigated. Commercial samples of yogurt and soy milk were used. These samples were inoculated with either 10(4) or 10(7) CFU of L. monocytogenes per ml. Sampling was carried out every 3 to 4 days initially and was then carried out weekly, for a total storage time of 31 days. Each time a sample was collected, the pH of the sample was measured. After 31 days, low-fat plain, low-fat vanilla, and nonfat plain yogurt samples inoculated with 10(4) CFU/ml showed 2.5-log reductions in viable cell populations, and nonfat vanilla yogurt showed a 3.5-log reduction. For yogurt inoculated with 10(7) CFU/ml, reductions of 2.5 log CFU/ml were observed for plain low-fat and nonfat yogurts, and reductions of 5 log CFU/ml were observed for vanilla-flavored low-fat and nonfat yogurts. In vanilla-flavored and plain low-fat and Plus soy milk samples, cell counts increased from 10(4) and 10(7) CFU/ml to 10(9) CFU/ml at 7 and 3 days of storage, respectively, at 8 degrees C. Coagulation in soy milk samples was observed when the cell population reached 10(9) CFU/ml. In soy milk, the L. monocytogenes population did not change for up to 31 days. Vanillin had an inhibitory effect on L. monocytogenes in yogurt but not in soy milk.
-
Nou, Xiangwu; Luo, Yaguang
2010-06-01
Currently, most fresh-cut processing facilities in the United States use chlorinated water or other sanitizer solutions for microbial reduction after lettuce is cut. Freshly cut lettuce releases significant amounts of organic matter that negatively impacts the effectiveness of chlorine or other sanitizers for microbial reduction. The objective of this study is to evaluate whether a sanitizer wash before cutting improves microbial reduction efficacy compared to a traditional postcutting sanitizer wash. Romaine lettuce leaves were quantitatively inoculated with E. coli O157:H7 strains and washed in chlorinated water before or after cutting, and E. coli O157:H7 cells that survived the washing process were enumerated to determine the effectiveness of microbial reduction for the 2 cutting and washing sequences. Whole-leaf washing in chlorinated water improved pathogen reduction by approximately 1 log unit over traditional cut-leaf sanitization. Similar improvement in the reduction of background microflora was also observed. Inoculated "Lollo Rossa" red lettuce leaves were mixed with noninoculated Green-Leaf lettuce leaves to evaluate pathogen cross-contamination during processing. High level (96.7% subsamples, average MPN 0.6 log CFU/g) of cross-contamination of noninoculated green leaves by inoculated red leaves was observed when mixed lettuce leaves were cut prior to washing in chlorinated water. In contrast, cross-contamination of noninoculated green leaves was significantly reduced (3.3% of subsamples, average MPN
-
Macinga, David R.; Sattar, Syed A.; Jaykus, Lee-Ann; Arbogast, James W.
2008-01-01
Norovirus is the leading cause of food-related illness in the United States, and contamination of ready-to-eat items by food handlers poses a high risk for disease. This study reports the in vitro (suspension test) and in vivo (fingerpad protocol) assessments of a new ethanol-based hand sanitizer containing a synergistic blend of polyquaternium polymer and organic acid, which is active against viruses of public health importance, including norovirus. When tested in suspension, the test product reduced the infectivity of the nonenveloped viruses human rotavirus (HRV), poliovirus type 1 (PV-1), and the human norovirus (HNV) surrogates feline calicivirus (FCV) F-9 and murine norovirus type 1 (MNV-1) by greater than 3 log10 after a 30-s exposure. In contrast, a benchmark alcohol-based hand sanitizer reduced only HRV by greater than 3 log10 and none of the additional viruses by greater than 1.2 log10 after the same exposure. In fingerpad experiments, the test product produced a 2.48 log10 reduction of MNV-1 after a 30-s exposure, whereas a 75% ethanol control produced a 0.91 log10 reduction. Additionally, the test product reduced the infectivity titers of adenovirus type 5 (ADV-5) and HRV by ≥3.16 log10 and ≥4.32 log10, respectively, by the fingerpad assay within 15 s; and PV-1 was reduced by 2.98 log10 in 30 s by the same method. Based on these results, we conclude that this new ethanol-based hand sanitizer is a promising option for reducing the transmission of enteric viruses, including norovirus, by food handlers and care providers. PMID:18586970
-
Macinga, David R; Sattar, Syed A; Jaykus, Lee-Ann; Arbogast, James W
2008-08-01
Norovirus is the leading cause of food-related illness in the United States, and contamination of ready-to-eat items by food handlers poses a high risk for disease. This study reports the in vitro (suspension test) and in vivo (fingerpad protocol) assessments of a new ethanol-based hand sanitizer containing a synergistic blend of polyquaternium polymer and organic acid, which is active against viruses of public health importance, including norovirus. When tested in suspension, the test product reduced the infectivity of the nonenveloped viruses human rotavirus (HRV), poliovirus type 1 (PV-1), and the human norovirus (HNV) surrogates feline calicivirus (FCV) F-9 and murine norovirus type 1 (MNV-1) by greater than 3 log(10) after a 30-s exposure. In contrast, a benchmark alcohol-based hand sanitizer reduced only HRV by greater than 3 log(10) and none of the additional viruses by greater than 1.2 log(10) after the same exposure. In fingerpad experiments, the test product produced a 2.48 log(10) reduction of MNV-1 after a 30-s exposure, whereas a 75% ethanol control produced a 0.91 log(10) reduction. Additionally, the test product reduced the infectivity titers of adenovirus type 5 (ADV-5) and HRV by > or =3.16 log(10) and > or =4.32 log(10), respectively, by the fingerpad assay within 15 s; and PV-1 was reduced by 2.98 log(10) in 30 s by the same method. Based on these results, we conclude that this new ethanol-based hand sanitizer is a promising option for reducing the transmission of enteric viruses, including norovirus, by food handlers and care providers.
-
The dynamic forces and moments required in handling tree-length logs.
John A. Sturos
1971-01-01
Realistic dynamic loading requirements for tree- or log-harvesting machines were determined. The study showed that dynamic forces and moments four times as great as those required statically can occur in the field.
-
Cap, Andrew P; Pidcoke, Heather F; Keil, Shawn D; Staples, Hilary M; Anantpadma, Manu; Carrion, Ricardo; Davey, Robert A; Frazer-Abel, Ashley; Taylor, Audra L; Gonzales, Richard; Patterson, Jean L; Goodrich, Raymond P
2016-03-01
Transfusion of plasma from recovered patients after Ebolavirus (EBOV) infection, typically called "convalescent plasma," is an effective treatment for active disease available in endemic areas, but carries the risk of introducing other pathogens, including other strains of EBOV. A pathogen reduction technology using ultraviolet light and riboflavin (UV+RB) is effective against multiple enveloped, negative-sense, single-stranded RNA viruses that are similar in structure to EBOV. We hypothesized that UV+RB is effective against EBOV in blood products without activating complement or reducing protective immunoglobulin titers that are important for the treatment of Ebola virus disease (EVD). Four in vitro experiments were conducted to evaluate effects of UV+RB on green fluorescent protein EBOV (EBOV-GFP), wild-type EBOV in serum, and whole blood, respectively, and on immunoglobulins and complement in plasma. Initial titers for Experiments 1 to 3 were 4.21 log GFP units/mL, 4.96 log infectious units/mL, and 4.23 log plaque-forming units/mL. Conditions tested in the first three experiments included the following: 1-EBOV-GFP plus UV+RB; 2-EBOV-GFP plus RB only; 3-EBOV-GFP plus UV only; 4-EBOV-GFP without RB or UV; 5-virus-free control plus UV only; and 6-virus-free control without RB or UV. UV+RB reduced EBOV titers to nondetectable levels in both nonhuman primate serum (≥2.8- to 3.2-log reduction) and human whole blood (≥3.0-log reduction) without decreasing protective antibody titers in human plasma. Our in vitro results demonstrate that the UV+RB treatment efficiently reduces EBOV titers to below limits of detection in both serum and whole blood. In vivo testing to determine whether UV+RB can improve convalescent blood product safety is indicated. © 2016 AABB.
-
Cap, Andrew P.; Pidcoke, Heather F.; Keil, Shawn D.; Staples, Hilary M.; Anantpadma, Manu; Carrion, Ricardo; Davey, Robert A.; Frazer-Abel, Ashley; Taylor, Audra L.; Gonzales, Richard; Patterson, Jean L.; Goodrich, Raymond P.
2018-01-01
BACKGROUND Transfusion of plasma from recovered patients after Ebolavirus (EBOV) infection, typically called ‘convalescent plasma,’ is an effective treatment for active disease available in endemic areas, but carries the risk of introducing other pathogens, including other strains of EBOV. A pathogen reduction technology using ultraviolet light and riboflavin (UV + RB) is effective against multiple enveloped, negative-sense, single-stranded RNA viruses that are similar in structure to EBOV. We hypothesized that UV + RB is effective against EBOV in blood products without activating complement or reducing protective immunoglobulin titers that are important for the treatment of ebolavirus disease (EVD). STUDY DESIGN AND METHODS Four in vitro experiments were conducted to evaluate effects of UV + RB on green fluorescent protein EBOV (EBOV-GFP), wild-type EBOV in serum and whole blood, respectively, and on immunoglobulins and complement in plasma. Initial titers for Experiments 1–3 were: 4.21 log10 GFP units/mL, 4.96 log10 infectious units per mL, and 4.23 log10 plaque forming units per mL (PFU/mL). Conditions tested in the first three experiments included: 1. EBOV-GFP + UV + RB; 2. EBOV-GFP + RB only; 3 EBOV-GFP + UV only; 4. EBOV-GFP without RB or UV; 5. Virus-free control + UV only; and 6. Virus-free control without RB or UV. RESULTS UV + RB reduced EBOV titers to non-detectable levels in both non-human primate serum (≥ 2.8 to 3.2 log reduction) and human whole blood (≥ 3.0 log reduction) without decreasing protective antibody titers in human plasma. CONCLUSION Our in vitro results demonstrate that the UV + RB treatment efficiently reduces EBOV titers to below limits of detection in both serum and whole blood. In vivo testing to determine whether UV + RB can improve convalescent blood product safety is indicated. PMID:27001363
-
Vaze, Nachiket; Jiang, Yi; Mena, Lucas; Zhang, Yipei; Bello, Dhimiter; Leonard, Stephen S; Morris, Anna M; Eleftheriadou, Mary; Pyrgiotakis, Georgios; Demokritou, Philip
2018-03-01
Engineered water nanostructures (EWNS) synthesized utilizing electrospray and ionization of water, have been, recently, shown to be an effective, green, antimicrobial platform for surface and air disinfection, where reactive oxygen species (ROS), generated and encapsulated within the particles during synthesis, were found to be the main inactivation mechanism. Herein, the antimicrobial potency of the EWNS was further enhanced by integrating electrolysis, electrospray and ionization of de-ionized water in the EWNS synthesis process. Detailed physicochemical characterization of these enhanced EWNS (eEWNS) was performed using state-of-the-art analytical methods and has shown that, while both size and charge remain similar to the EWNS (mean diameter of 13 nm and charge of 13 electrons), they possess a three times higher ROS content. The increase of the ROS content as a result of the addition of the electrolysis step before electrospray and ionization led to an increased antimicrobial ability as verified by E. coli inactivation studies using stainless steel coupons. It was shown that a 45-minute exposure to eEWNS resulted in a 4-log reduction as opposed to a 1.9-log reduction when exposed to EWNS. In addition, the eEWNS were assessed for their potency to inactivate natural microbiota (total viable and yeast and mold counts), as well as, inoculated E.coli on the surface of fresh organic blackberries. The results showed a 97% (1.5-log) inactivation of the total viable count, a 99% (2-log) reduction in the yeast and mold count and a 2.5-log reduction of the inoculated E.coli after 45 minutes of exposure, without any visual changes to the fruit. This enhanced antimicrobial activity further underpins the EWNS platform as an effective, dry and chemical free approach suitable for a variety of food safety applications and could be ideal for delicate fresh produce that cannot withstand the classical, wet disinfection treatments.
-
Park, Shin Young; Kang, Sujin; Ha, Sang-Do
2016-06-01
This study investigated the effects of gamma radiation (3-10 kGy) upon the inactivation of murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate. The edible green and brown algae, fulvescens (Capsosiphon fulvescens) and fusiforme (Hizikia fusiforme), respectively, were experimentally contaminated with 5-6 log10 plaque forming units (PFU)/ml MNV-1. The titer of MNV-1 significantly decreased (P < 0.05) as the dose of gamma radiation increased. MNV-1 titer decreased to 1.16-2.46 log10 PFU/ml in fulvescens and 0.37-2.21 log10 PFU/ml in fusiforme following irradiation. However, all Hunters ('L', 'a' and 'b') and sensory qualities (appearance, color, flavor, texture and overall acceptability) were not significantly (P > 0.05) different in both algae following gamma radiation. The Weibull model was used to generate non-linear survival curves and to calculate Gd values for 1, 2, and 3 log10 reductions of MNV-1 in fulvescens (R(2) = 0.992) and fusiforme (R(2) = 0.988). A Gd value of 1 (90% reduction) corresponded to 2.89 and 3.93 kGy in fulvescens and fusiforme, respectively. A Gd value of 2 (99% reduction) corresponded to 7.75 and 9.02 kGy in fulvescens and fusiforme, respectively, while a Gd value of 3 (99.9% reduction) in fulvescens and fusiforme corresponded with 13.83 and 14.93 kGy of gamma radiation, respectively. A combination of gamma radiation at medium doses and other treatments could be used to inactivate ≥ 3 log10 PFU/ml NoV in seaweed. The inactivation kinetics due to gamma radiation against NoV in these algae might provide basic information for use in seaweed processing and distribution. Copyright © 2015. Published by Elsevier Ltd.
-
Zhang, Hongyin; Oyanedel-Craver, Vinka
2013-09-15
This study compares the disinfection performance of ceramic water filters impregnated with two antibacterial compounds: silver nanoparticles and a polymer based quaternary amine functiaonalized silsesquioxane (poly(trihydroxysilyl) propyldimethyloctadecyl ammonium chloride (TPA)). This study evaluated these compounds using ceramic disks manufactures with clay obtained from a ceramic filter factory located in San Mateo Ixtatan, Guatemala. Instead of using full size ceramic water filters, manufactured 6.5 cm diameter ceramic water filter disks were used. Results showed that TPA can achieve a log bacterial reduction value of 10 while silver nanoparticles reached up to 2 log reduction using a initial concentration of bacteria of 10(10)-10(11)CFU/ml. Similarly, bacterial transport demonstrated that ceramic filter disks painted with TPA achieved a bacterial log reduction value of 6.24, which is about 2 log higher than the values obtained for disks painted with silver nanoparticles (bacterial log reduction value: 4.42). The release of both disinfectants from the ceramic materials to the treated water was determined measuring the effluent concentrations in each test performed. Regarding TPA, about 3% of the total mass applied to the ceramic disks was released in the effluent over 300 min, which is slightly lower than the release percentage for silver nanoparticles (4%). This study showed that TPA provides a comparable disinfection performance than silver nanoparticles in ceramic water filter. Another advantage of using TPA is the cost as the price of TPA is considerable lower than silver nanoparticles. In spite of the use of TPA in several medical related products, there is only partial information regarding the health risk associated with the ingestion of this compound. Additional long-term toxicological information for TPA should be evaluated before its future application in ceramic water filters. Copyright © 2013 Elsevier B.V. All rights reserved.
-
Reduction of Aeromonas hidrophyla biofilm on stainless stell surface by essential oils
Millezi, Alessandra Farias; Cardoso, Maria das Graças; Alves, Eduardo; Piccoli, Roberta Hilsdorf
2013-01-01
This study demonstrates the possibility of using sanitizing detergents based on natural products for the elimination and/or reduction of Aeromonas hydrophila biofilm formed on stainless steel surfaces. The goal of this work was to determine the reduction effect of sanitizing detergents containing essential oils of Thymus vulgaris (thyme) and Cymbopogon citratus (lemongrass) on biofilm formed by A. hydrophila on AISI 304 stainless steel coupons, using UHT skimmed milk as substratum. There was adhesion and biofilm formation by A. hydrophila at 28 °C, presenting 7.60 log cfu.cm−2 after the fourth day of cultivation. There was no significant difference between the lemongrass treatment and that of the thyme oil (p < 0.05). However, both treatments significantly reduced the biofilm, differing significantly from the NaOH control (p > 0.05). The treatment with lemongrass solution reduced the biofilm by 4.51 log cfu cm−2 at 25 °C. The thyme detergent also reduced the number of cfu cm−2 by 3.84 log cycles at 25 °C. The use of the lemongrass and thyme solutions efficiently reduced the A. hydrophila biofilm. PMID:24159286
-
Amin, Nuhu; Pickering, Amy J.; Ram, Pavani K.; Unicomb, Leanne; Najnin, Nusrat; Homaira, Nusrat; Ashraf, Sania; Abedin, Jaynal; Islam, M. Sirajul; Luby, Stephen P.
2014-01-01
We conducted a randomized, non-inferiority field trial in urban Dhaka, Bangladesh among mothers to compare microbial efficacy of soapy water (30 g powdered detergent in 1.5 L water) with bar soap and water alone. Fieldworkers collected hand rinse samples before and after the following washing regimens: scrubbing with soapy water for 15 and 30 seconds; scrubbing with bar soap for 15 and 30 seconds; and scrubbing with water alone for 15 seconds. Soapy water and bar soap removed thermotolerant coliforms similarly after washing for 15 seconds (mean log10 reduction = 0.7 colony-forming units [CFU], P < 0.001 for soapy water; mean log10 reduction = 0.6 CFU, P = 0.001 for bar soap). Increasing scrubbing time to 30 seconds did not improve removal (P > 0.05). Scrubbing hands with water alone also reduced thermotolerant coliforms (mean log10 reduction = 0.3 CFU, P = 0.046) but was less efficacious than scrubbing hands with soapy water. Soapy water is an inexpensive and microbiologically effective cleansing agent to improve handwashing among households with vulnerable children. PMID:24914003
-
Luppens, S B; Abee, T; Oosterom, J
2001-04-01
The difference in killing exponential- and stationary-phase cells of Listeria monocytogenes by benzalkonium chloride (BAC) was investigated by plate counting and linked to relevant bioenergetic parameters. At a low concentration of BAC (8 mg liter(-1)), a similar reduction in viable cell numbers was observed for stationary-phase cells and exponential-phase cells (an approximately 0.22-log unit reduction), although their membrane potential and pH gradient were dissipated. However, at higher concentrations of BAC, exponential-phase cells were more susceptible than stationary-phase cells. At 25 mg liter(-1), the difference in survival on plates was more than 3 log units. For both types of cells, killing, i.e., more than 1-log unit reduction in survival on plates, coincided with complete inhibition of acidification and respiration and total depletion of ATP pools. Killing efficiency was not influenced by the presence of glucose, brain heart infusion medium, or oxygen. Our results suggest that growth phase is one of the major factors that determine the susceptibility of L. monocytogenes to BAC.
-
Organic acids for control of Salmonella in different feed materials.
Koyuncu, Sevinc; Andersson, Mats Gunnar; Löfström, Charlotta; Skandamis, Panagiotis N; Gounadaki, Antonia; Zentek, Jürgen; Häggblom, Per
2013-04-18
Salmonella control in animal feed is important in order to protect animal and public health. Organic acids is one of the control measures used for treatment of Salmonella contaminated feed or feed ingredients. In the present study, the efficacy of formic acid (FA) and different blends of FA, propionic acid (PA) and sodium formate (SF) was investigated. Four Salmonella strains isolated from feed were assayed for their acid tolerance. Also, the effect of lower temperatures (5°C and 15°C) compared to room temperature was investigated in rape seed and soybean meal. The efficacy of acid treatments varied significantly between different feed materials. The strongest reduction was seen in pelleted and compound mash feed (2.5 log10 reduction) followed by rapeseed meal (1 log10 reduction) after 5 days exposure. However, in soybean meal the acid effects were limited (less than 0.5 log10 reduction) even after several weeks' exposure. In all experiments the survival curves showed a concave shape, with a fast initial death phase followed by reduction at a slower rate during the remaining time of the experiment.No difference in Salmonella reduction was observed between FA and a blend of FA and PA, whereas a commercial blend of FA and SF (Amasil) was slightly more efficacious (0.5-1 log10 reduction) than a blend of FA and PA (Luprocid) in compound mash feed. The Salmonella Infantis strain was found to be the most acid tolerant strain followed by, S. Putten, S. Senftenberg and S. Typhimurium. The tolerance of the S. Infantis strain compared with the S. Typhimurium strain was statistically significant (p<0.05). The lethal effect of FA on the S. Typhimurium strain and the S. Infantis strain was lower at 5°C and 15°C compared to room temperatures. Acid treatment of Salmonella in feed is a matter of reducing the number of viable bacterial cells rather than eliminating the organism. Recommendations on the use of acids for controlling Salmonella in feed should take into account the relative efficacy of acid treatment in different feed materials, the variation in acid tolerance between different Salmonella strains, and the treatment temperature.
-
Li, Jiao; Ding, Tian; Liao, Xinyu; Chen, Shiguo; Ye, Xingqian; Liu, Donghong
2017-09-01
This study evaluated the synergetic effects of ultrasound and slightly acidic electrolyzed water (SAEW) on the inactivation of Staphylococcus aureus using flow cytometry and electron microscopy. The individual ultrasound treatment for 10min only resulted in 0.36logCFU/mL reductions of S. aureus, while the SAEW treatment alone for 10min resulted in 3.06logCFU/mL reductions. The log reductions caused by combined treatment were enhanced to 3.68logCFU/mL, which were greater than the sum of individual treatments. This phenomenon was referred to as synergistic effects. FCM analysis distinguished live and dead cells as well as revealed dynamic changes in the physiological states of S. aureus after different treatments. The combined treatment greatly reduced the number of viable but nonculturable (VBNC) bacteria to 0.07%; in contrast, a single ultrasound treatment for 10min induced the formation of VBNC cells to 45.75%. Scanning and transmission electron microscopy analysis revealed that greater damage to the appearance and ultrastructure of S. aureus were achieved after combined ultrasound-SAEW treatment compared to either treatment alone. These results indicated that combining ultrasound with SAEW is a promising sterilization technology with potential uses for environmental remediation and food preservation. Copyright © 2016 Elsevier B.V. All rights reserved.
-
Hammer, P; Richter, E; Rüsch-Gerdes, S; Walte, H-G C; Matzen, S; Kiesner, C
2015-03-01
Experiments to determine the efficacy of high temperature, short time (HTST) pasteurization of milk in terms of inactivation of pathogenic microorganisms were mainly performed between 1930 and 1960. Among the target organisms were Mycobacterium bovis and Mycobacterium tuberculosis. As a result, the Codex Alimentarius prescribes that HTST treatment of milk should lead to a significant reduction of pathogenic microorganisms during milk pasteurization. Due to the development of improved methods for the detection of survivors and of more advanced heating technology, verification of this requirement seemed to be necessary. To address recent outbreaks of tuberculosis in cattle caused by M. bovis ssp. caprae (M. caprae) in the southern regions of Germany, this organism was tested and compared with M. bovis ssp. bovis (M. bovis). Experiments were performed in a pilot plant for HTST pasteurization of milk with 3 strains of M. caprae and 1 strain of M. bovis. In preliminary trials at a fixed holding time of 25 s, the temperature at which significant inactivation occurred was 62.5°C for all strains. To determine D-values (decimal reduction times) for the inactivation kinetics, the strains were tested at 65, 62.5, and 60°C at holding times of 16.5, 25, and 35 s. At 65°C, the D-values of all strains ranged from 6.8 to 7.8 s, and at 62.5°C, D-values ranged from 14.5 to 18.1 s. Low inactivation was observed at 60°C. When the low slope of the inactivation curve allowed calculation of a D-value, these ranged from 40.8 to 129.9 s. In terms of log10 reductions, the highest values for all strains were 4.1 to 4.9 log at 65°C, with a holding time of 35 s. The tested strains of M. caprae and M. bovis showed similar low resistance to heat. Standard HTST treatment should result in a high reduction of these organisms and thus the requirements of the Codex Alimentarius for inactivation of pathogens by this process are far exceeded. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
-
Moreno-Andrés, Javier; Ambauen, Noëmi; Vadstein, Olav; Hallé, Cynthia; Acevedo-Merino, Asunción; Nebot, Enrique; Meyn, Thomas
2018-05-03
Seawater treatment is increasingly required due to industrial activities that use substantial volumes of seawater in their processes. The shipping industry and the associated management of a ship's ballast water are currently considered a global challenge for the seas. Related to that, the suitability of an Electrochemical Advanced Oxidation Process (EAOP) with Boron Doped Diamond (BDD) electrodes has been assessed on a laboratory scale for the disinfection of seawater. This technology can produce both reactive oxygen species and chlorine species (especially in seawater) that are responsible for inactivation. The EAOP was applied in a continuous-flow regime with real seawater. Natural marine heterotrophic bacteria (MHB) were used as an indicator of disinfection efficiency. A biphasic inactivation kinetic model was fitted on experimental points, achieving 4-Log reductions at 0.019 Ah L -1 . By assessing regrowth after treatment, results suggest that higher bacterial damages result from the EAOP when it is compared to chlorination. Furthermore, several issues lacking fundamental understanding were investigated such as recolonization capacity or bacterial community dynamics. It was concluded that, despite disinfection processes being effective, there is not only a possibility for regrowth after treatment but also a change on bacterial population diversity produced by the treatment. Finally, energy consumption was estimated and indicated that 0.264 kWh·m -3 are needed for 4.8-Log reductions of MHB; otherwise, with 0.035 kWh·m -3 , less disinfection efficiency can be obtained (2.2-Log red). However, with a residual oxidant in the solution, total inactivation can be achieved in three days. Copyright © 2018 Elsevier Ltd. All rights reserved.
-
Low Temperature Plasma for decontamination of E. coli in milk.
Gurol, C; Ekinci, F Y; Aslan, N; Korachi, M
2012-06-15
Raw milk is a natural, highly nutritious product and a quick and easy supplement for human dietary requirements. Elimination of bacteria in milk has been a problem for decades and new methods with regards to non-thermal applications which do not harm the chemical composition of milk, are currently under investigation. The objective of the study was to determine the potential use of a novel, Low Temperature Plasma (LTP) system for its capability of killing Escherichia coli in milk with different fat contents. The time dependent effect of atmospheric corona discharge generated with 9kV of AC power supply on E. coli ATCC 25922 dispersed in whole, semi skimmed and skimmed milk was examined. Plasma was applied at time intervals of 0, 3, 6, 9, 12, 15 and 20min. A significant 54% reduction in the population of E. coli cells after only 3min was observed regardless of the fat content of the milk. The initial pre-plasma bacterial count of 7.78 Log CFU/ml in whole milk was decreased to 3.63 Log CFU/ml after 20min of plasma application. LTP did not cause any significant change to the pH and color values of raw milk samples. No viable cells were detected after one week examination in whole milk samples and remained so over the 6week storage period. The findings of this study show that the novel LTP system tested was able to significantly reduce E. coli in milk by more than a 3 fold log reduction without significantly affecting pH or color properties. Copyright © 2012 Elsevier B.V. All rights reserved.
-
Pearce, Lindsay E.; Truong, H. Tuan; Crawford, Robert A.; Yates, Gary F.; Cavaignac, Sonia; de Lisle, Geoffrey W.
2001-01-01
A pilot-scale pasteurizer operating under validated turbulent flow (Reynolds number, 11,050) was used to study the heat sensitivity of Mycobacterium avium subsp. paratuberculosis added to raw milk. The ATCC 19698 type strain, ATCC 43015 (Linda, human isolate), and three bovine isolates were heated in raw whole milk for 15 s at 63, 66, 69, and 72°C in duplicate trials. No strains survived at 72°C for 15 s; and only one strain survived at 69°C. Means of pooled D values (decimal reduction times) at 63 and 66°C were 15.0 ± 2.8 s (95% confidence interval) and 5.9 ± 0.7 s (95% confidence interval), respectively. The mean extrapolated D72°C was <2.03 s. This was equivalent to a >7 log10 kill at 72°C for 15 s (95% confidence interval). The mean Z value (degrees required for the decimal reduction time to traverse one log cycle) was 8.6°C. These five strains showed similar survival whether recovery was on Herrold's egg yolk medium containing mycobactin or by a radiometric culture method (BACTEC). Milk was inoculated with fresh fecal material from a high-level fecal shedder with clinical Johne's disease. After heating at 72°C for 15 s, the minimum M. avium subsp. paratuberculosis kill was >4 log10. Properly maintained and operated equipment should ensure the absence of viable M. avium subsp. paratuberculosis in retail milk and other pasteurized dairy products. An additional safeguard is the widespread commercial practice of pasteurizing 1.5 to 2° above 72°C. PMID:11525992
-
Establishment of a multi-species biofilm model to evaluate chlorhexidine efficacy.
Touzel, R E; Sutton, J M; Wand, M E
2016-02-01
Chronic infections, for example, diabetic foot ulcers, have a large impact in terms of patient morbidity and mortality. These wounds are characterized by complex polymicrobial communities of bacteria, which may include a number of difficult-to-eradicate multidrug-resistant pathogens. To establish a multi-species biofilm model to test the efficacy of chlorhexidine and chlorhexidine-containing formulas in eradication of polymicrobial biofilms. A Centers for Disease Control and Prevention bioreactor was used to establish a multi-species biofilm incorporating Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis with equal numbers of each pathogen. This model was used to test the effectiveness of chlorhexidine at controlling the pre-formed biofilm. Chlorhexidine digluconate (CHD) was added to the bioreactor at a range of concentrations. K. pneumoniae and P. aeruginosa survived within multi-species biofilms, up to and including 4% CHD, whereas S. aureus was reduced to below the level of detection at 1%. Wiping the biofilm-containing coupons from the bioreactor with chlorhexidine-containing medical wipes resulted in >3 to <4log10 reduction after 24h, for all species. When the coupons were embedded in a simulated wound bed, formed in an agar plate, CHD-containing medical dressings completely eliminated S. aureus (>8log10 reduction), but had minimal effect (<3log10) against the other species tested. The study demonstrates that the effectiveness of chlorhexidine may be limited in settings where it is required to act on multi-species biofilms. This may compromise the ability of chlorhexidine to control the infection and spread of these pathogens. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.
-
Kinetics of Hydrothermal Inactivation of Endotoxins ▿
Li, Lixiong; Wilbur, Chris L.; Mintz, Kathryn L.
2011-01-01
A kinetic model was established for the inactivation of endotoxins in water at temperatures ranging from 210°C to 270°C and a pressure of 6.2 × 106 Pa. Data were generated using a bench scale continuous-flow reactor system to process feed water spiked with endotoxin standard (Escherichia coli O113:H10). Product water samples were collected and quantified by the Limulus amebocyte lysate assay. At 250°C, 5-log endotoxin inactivation was achieved in about 1 s of exposure, followed by a lower inactivation rate. This non-log-linear pattern is similar to reported trends in microbial survival curves. Predictions and parameters of several non-log-linear models are presented. In the fast-reaction zone (3- to 5-log reduction), the Arrhenius rate constant fits well at temperatures ranging from 120°C to 250°C on the basis of data from this work and the literature. Both biphasic and modified Weibull models are comparable to account for both the high and low rates of inactivation in terms of prediction accuracy and the number of parameters used. A unified representation of thermal resistance curves for a 3-log reduction and a 3 D value associated with endotoxin inactivation and microbial survival, respectively, is presented. PMID:21193667
-
NASA Technical Reports Server (NTRS)
Collazo, Carlimar
2011-01-01
The statement of purpose is to analyze network monitoring logs to support the computer incident response team. Specifically, gain a clear understanding of the Uniform Resource Locator (URL) and its structure, and provide a way to breakdown a URL based on protocol, host name domain name, path, and other attributes. Finally, provide a method to perform data reduction by identifying the different types of advertisements shown on a webpage for incident data analysis. The procedures used for analysis and data reduction will be a computer program which would analyze the URL and identify and advertisement links from the actual content links.
-
47 CFR 73.1800 - General requirements related to the station log.
Code of Federal Regulations, 2010 CFR
2010-10-01
... knowledge of the facts required. All entries, whether required or not by the provisions of this part, must... representation of what transpired. (b) The logs shall be kept in an orderly and legible manner, in suitable form...
-
47 CFR 73.1800 - General requirements related to the station log.
Code of Federal Regulations, 2012 CFR
2012-10-01
... knowledge of the facts required. All entries, whether required or not by the provisions of this part, must... representation of what transpired. (b) The logs shall be kept in an orderly and legible manner, in suitable form...
-
47 CFR 73.1800 - General requirements related to the station log.
Code of Federal Regulations, 2011 CFR
2011-10-01
... knowledge of the facts required. All entries, whether required or not by the provisions of this part, must... representation of what transpired. (b) The logs shall be kept in an orderly and legible manner, in suitable form...
-
Lee, Kwang-Il; Lee, Jung-Soo; Jung, Hong-Hee; Lee, Hwa-Yong; Moon, Seong-Hwan; Kang, Kyoung-Tak; Shim, Young-Bock; Jang, Ju-Woong
2012-01-01
Xenografts, unlike other grafting products, cannot be commercialized unless they conform to stringent safety regulations. Particularly with bovine-derived materials, it is essential to remove viruses and inactivate infectious factors because of the possibility that raw materials are imbrued with infectious viruses. The removal of the characteristics of infectious viruses from the bovine bone grafting materials need to be proved and inactivation process should satisfy the management provision of the Food and Drug Administration (FDA). To date, while most virus inactivation studies were performed in human allograft tissues, there have been almost no studies on bovine bone. To evaluate the efficacy of virus inactivation after treatment of bovine bone with 70% ethanol, 4% sodium hydroxide, and gamma irradiation, we selected a variety of experimental model viruses that are known to be associated with bone pathogenesis, including bovine parvovirus (BPV), bovine herpes virus (BHV), bovine viral diarrhea virus (BVDV), and bovine parainfluenza-3 virus (BPIV-3). The cumulative virus log clearance factor or cumulative virus log reduction factor for the manufacturing process was obtained by calculating the sum of the individual virus log clearance factors or log reduction factors determined for individual process steps with different physicochemical methods. The cumulative log clearance factors achieved by three different virus inactivation processes were as follows: BPV ≥ 17.73, BHV ≥ 20.53, BVDV ≥ 19.00, and BPIV-3 ≥ 16.27. On the other hand, the cumulative log reduction factors achieved were as follows: BPV ≥ 16.95, BHV ≥ 20.22, BVDV ≥ 19.27, and BPIV-3 ≥ 15.58. Treatment with 70% ethanol, 4% sodium hydroxide, or gamma irradiation was found to be very effective in virus inactivation, since all viruses were at undetectable levels during each process. We have no doubt that application of this established process to bovine bone graft manufacture will be effective and essential. © 2012 John Wiley & Sons A/S.
-
Clearwater, M J; Susilawaty, R; Effendi, R; van Gardingen, P R
1999-12-01
This study examined the photosynthetic acclimation of pre-existing Shorea johorensis (Dipterocarpaceae) seedlings to the change in conditions that occurs at the time of logging in Central Kalimantan, Indonesia. The hypothesis was that the seedlings would be unable to acclimate beyond partially open conditions after canopy disturbance caused by logging, therefore limiting the potential for regeneration in the most open areas. Bleaching and reductions in the predawn ratio of variable to maximum fluorescence (F v /F m ) indicated chronic photoinhibition and damage to the previously shade-adapted leaves of seedlings in an area logged 2 weeks earlier. The majority of seedlings in partially open and open environments of an area logged 3 months earlier were already growing fast. Leaves that had developed in the new environment showed only small reductions in predawn F v /F m and large increases in the light saturated rate of photosynthesis (A max ) per unit area when compared to shaded seedlings. Leaves in the most open environments had higher but more variable nitrogen concentrations, A max per unit area and A max per unit mass when compared to seedlings in partially open environments. Increases in dark respiration were disproportionately large compared to increases in A max , and may have been the result of increased investment in photoprotective mechanisms. The response of stomatal conductance to the vapour pressure deficit and leaf temperature was examined, but it suggested only a 10% reduction in daily leaf level carbon gain in open environments. The ratio of leaf area to fine root mass was highest in shade-suppressed and newly exposed seedlings, suggesting a potential hydraulic limitation to transpiration during acclimation. However, rainfall during this period was high and leaf water potentials did not differ between disturbed and undisturbed environments. S. johorensis seedlings were capable of significant acclimation to conditions more extreme than partial canopy opening. Low seedling density after logging during the wet season cannot be explained by a limited potential for photosynthetic acclimation.
-
Inactivation of Salmonella on pecan nutmeats by hot air treatment and oil roasting.
Beuchat, Larry R; Mann, David A
2011-09-01
Studies were done to determine the effectiveness of hot air drying, dry roasting, and oil roasting in killing Salmonella on pecan nutmeats. Pecan halves and pieces were inoculated by immersion in a five-serotype suspension of Salmonella or by surface application of powdered chalk containing the pathogen. Hot air treatment of low-moisture (2.8 to 4.1%) and high-moisture (10.5 to 11.2%) immersion-inoculated nutmeats (initial population, 6.18 to 7.16 log CFU/g) at 120°C for 20 min reduced the number of Salmonella by 1.18 to 1.26 and 1.89 to 2.04 log CFU/g, respectively. However, regardless of the moisture content, hot air treatment of pecan halves containing 0.77 log CFU/g at 120°C for 20 min failed to eliminate Salmonella. Reductions were >7 log CFU/g when dry pieces were dry roasted at 160°C for 15 min. Treatment of halves at 140°C for 20 min, 150°C for 15 min, or 170°C for 10 min reduced Salmonella by 5 log CFU/g. The pathogen was slightly more heat resistant in immersion-inoculated nutmeats than on surface-inoculated nutmeats. Exposure of immersion-inoculated pieces to peanut oil at 127°C for 1.5 min or 132°C for 1.0 min reduced the number of Salmonella by 5 log CFU/g. Treatment of halves at 138°C for 2.0 min reduced Salmonella by 5 log CFU/g; treatment at 132°C for 2.5 to 4.0 min did not always achieve this reduction. Hot air treatment cannot be relied upon to reduce Salmonella by 5 log CFU/g of raw pecan nutmeats without changing sensory qualities. Treatment temperatures and times typically used to oil roast nutmeats appear to be sufficient to reduce Salmonella by 5 log CFU/g.
-
Use of household bleach for emergency disinfection of drinking water.
Elmaksoud, Sherif Abd; Patel, Nikita; Maxwell, Sherri L; Sifuentes, Laura Y; Gerba, Charles P
2014-05-01
Household bleach is typically used as a disinfectant for water in times of emergencies and by those engaging in recreational activities such as camping or rafting. The Centers for Disease Control and Prevention recommend a concentration of free chlorine of 1 mg/L for 30 minutes, or about 0.75 mL (1/8 teaspoon) of household bleach per gallon of water. The goal of the study described in this article was to assess two household bleach products to kill waterborne bacteria and viruses using the test procedures in the U.S. Environmental Protection Agency's Guide Standard and Protocol for Testing Microbiological Purifiers. Bleach was found to meet these requirements in waters of low turbidity and organic matter. While the test bacterium was reduced by six logs in high turbid and organic-laden waters, the test viruses were reduced only by one-half to one log. In such waters greater chlorine doses or contact times are needed to achieve greater reduction of viruses.
-
Hill, Andrew A; Simons, Robin L; Swart, Arno N; Kelly, Louise; Hald, Tine; Snary, Emma L
2016-03-01
As part of the evidence base for the development of national control plans for Salmonella spp. in pigs for E.U. Member States, a quantitative microbiological risk assessment was funded to support the scientific opinion required by the EC from the European Food Safety Authority. The main aim of the risk assessment was to assess the effectiveness of interventions implemented on-farm and at the abattoir in reducing human cases of pig meat-borne salmonellosis, and how the effects of these interventions may vary across E.U. Member States. Two case study Member States have been chosen to assess the effect of the interventions investigated. Reducing both breeding herd and slaughter pig prevalence were effective in achieving reductions in the number of expected human illnesses in both case study Member States. However, there is scarce evidence to suggest which specific on-farm interventions could achieve consistent reductions in either breeding herd or slaughter pig prevalence. Hypothetical reductions in feed contamination rates were important in reducing slaughter pig prevalence for the case study Member State where prevalence of infection was already low, but not for the high-prevalence case study. The most significant reductions were achieved by a 1- or 2-log decrease of Salmonella contamination of the carcass post-evisceration; a 1-log decrease in average contamination produced a 90% reduction in human illness. The intervention analyses suggest that abattoir intervention may be the most effective way to reduce human exposure to Salmonella spp. However, a combined farm/abattoir approach would likely have cumulative benefits. On-farm intervention is probably most effective at the breeding-herd level for high-prevalence Member States; once infection in the breeding herd has been reduced to a low enough level, then feed and biosecurity measures would become increasingly more effective. © 2016 Society for Risk Analysis.
-
Heir, E; Holck, A L; Omer, M K; Alvseike, O; Høy, M; Måge, I; Axelsson, L
2010-07-15
Outbreaks of verotoxigenic Escherichia coli (VTEC) linked to dry-fermented sausages (DFSs) have emphasized the need for DFS manufacturers to introduce measures to obtain enhanced safety and still maintain the sensory qualities of their products. To our knowledge no data have yet been reported on non-O157:H7 VTEC survival in DFS. Here, the importance of recipe and process variables on VTEC (O157:H7 and O103:H25) reductions in two types of DFS, morr and salami, was determined through three statistically designed experiments. Linear regression and ANOVA analyses showed that no single variable had a dominant effect on VTEC reductions. High levels of NaCl, NaNO(2), glucose (low pH) and fermentation temperature gave enhanced VTEC reduction, while high fat and large casing diameter (a(w)) gave the opposite effect. Interaction effects were small. The process and recipe variables showed similar effects in morr and salami. In general, recipes combining high batter levels of salt (NaCl and NaNO(2)) and glucose along with high fermentation temperature that gave DFS with low final pH and a(w), provided approximately 3 log(10) reductions compared to approximately 1.5 log(10) reductions obtained for standard recipe DFS. Storage at 4 degrees C for 2 months provided log(10) 0.33-0.95 additional VTEC reductions and were only marginally affected by recipe type. Sensory tests revealed only small differences between the various recipes of morr and salami. By optimisation of recipe and process parameters, it is possible to obtain increased microbial safety of DFS while maintaining the sensory qualities of the sausages. 2010 Elsevier B.V. All rights reserved.
-
Bactericidal effects of wine on Vibrio parahaemolyticus in oysters.
Liu, Chengchu; Chen, Ruiying; Su, Yi-Cheng
2006-08-01
The bactericidal effects of wines on Vibrio parahaemolyticus in oysters were studied to evaluate potential inactivation of V. parahaemolyticus in contaminated oysters by wine consumption. Shucked whole oyster and oyster meat homogenate were inoculated with V. parahaemolyticus and mixed with red or white wine. Survivals of V. parahaemolyticus in inoculated oysters were determined at 7 and 25 degrees C. Populations of V. parahaemolyticus in inoculated whole oysters (5.52 log most probable number [MPN] per g) decreased slightly to 4.90 log MPN/g (a 0.62-log reduction) after 24 h at 7 degrees C but increased to 7.37 log MPN/g over the same period at 25 degrees C. However, the populations in wine-treated whole oysters decreased by >1.7 and >1.9 log MPN/g after 24 h at 7 and 25 degrees C, respectively. Both red and white wines were more effective in inactivating V. parahaemolyticus in oyster meat homogenate than in whole oyster. Populations of V. parahaemolyticus in oyster meat homogenate (7.8 x 10(3) MPN/g) decreased rapidly to nondetectable levels (< 3 MPN/g) after 30 min of mixing with wine at 25 degrees C (a 3.89-log MPN/g reduction). These results suggest that chewing oysters before swallowing when eating raw oysters may result in greater inactivation of V. parahaemolyticus if wine is consumed. More studies are needed to determine the bactericidal effects of wine on V. parahaemolyticus in the complicated stomach environment.
-
Kenters, Nikki; Huijskens, Elisabeth G W; de Wit, Sophie C J; van Rosmalen, Joost; Voss, Andreas
2017-08-01
Hospital rooms play an important role in the transmission of several health care-associated pathogens. During the last few years, a number of innovative cleaning-disinfecting products have been brought to market. In this study, commercially available products combining cleaning and disinfection were compared, using 2 different application methods. The aim was to determine which product was most effective in simultaneous cleaning and disinfection of surfaces. Seven cleaning-disinfecting wipes and sprays based on different active ingredients were tested for their efficacy in removal of microbial burden and proteins. Efficacy was tested with known Dutch outbreak strains: vancomycin-resistant enterococci (VRE), Klebsiella pneumoniae OXA-48, or Acinetobacter baumannii. For all bacteria, ready-to-use cleaning-disinfecting products reduced the microbial count with a log 10 reduction >5 with a 5-minute exposure time, with the exception of a spray based on hydrogen peroxide. Omitting the aforementioned hydrogen peroxide spray, there were no significant differences between use of a wipe or spray in bacterial load reduction. Using adenosine triphosphate (ATP) measurements, a significant difference in log 10 relative light units (RLU) reduction between various bacteria (P ≤ .001) was observed. In general, a >5 log 10 reduction of colony forming units (CFU) for tested wipes and sprays was obtained for all tested bacteria strains, with exception of hydrogen peroxide spray and VRE. Although ATP may show a difference between pre- and postcleaning, RLU reduction does not correlate with actual CFU reductions. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
-
Tyan, Kevin; Kang, Jason; Jin, Katherine; Kyle, Aaron M
2018-05-23
A novel color additive colorizes chlorine disinfectants blue to improve visibility and enhance spray surface coverage, and it fades to colorless to indicate elapsed contact time. We investigated its interactions with 3 chlorine disinfectants to determine if the additive would adversely affect the disinfectants' antimicrobial efficacy or skin safety. We tested 0.5% sodium hypochlorite, 0.2% calcium hypochlorite, and 0.5% sodium dichloroisocyanurate (NaDCC) alone versus with color additive. An independent laboratory tested efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio cholerae, and human coronavirus 229E. An independent laboratory also tested direct skin irritation. Chlorine disinfectants with and without color additive achieved equal levels of efficacy against the tested pathogens. Against S. aureus, 0.5% sodium hypochlorite with and without color additive met Environmental Protection Agency criteria for disinfection success. Against human coronavirus 229E, 0.5% sodium hypochlorite alone failed disinfection success criteria, whereas 0.5% sodium hypochlorite with color additive achieved full viral inactivation (≥4.50 log 10 reduction). Against V. cholerae, 0.2% calcium hypochlorite alone and with color additive achieved 5.99 log 10 and >6.03 log 10 reductions, respectively. Against S. aureus and P. aeruginosa, 0.5% NaDCC with and without color additive achieved >4.9 log 10 and >3.54 log 10 reductions, respectively. All 3 chlorine disinfectants with color additive tested as negligible skin irritants. This color additive can be combined with chlorine disinfectants without adversely affecting antimicrobial efficacy or skin safety. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
-
Calle, Alexandra; Porto-Fett, Anna C S; Shoyer, Bradley A; Luchansky, John B; Thippareddi, Harshavardhan
2015-12-01
Boneless beef rib eye roasts were surface inoculated on the fat side with ca. 5.7 log CFU/g of a five-strain cocktail of Salmonella for subsequent searing, cooking, and warm holding using preparation methods practiced by restaurants surveyed in a medium-size Midwestern city. A portion of the inoculated roasts was then passed once through a mechanical blade tenderizer. For both intact and nonintact roasts, searing for 15 min at 260°C resulted in reductions in Salmonella populations of ca. 0.3 to 1.3 log CFU/g. For intact (nontenderized) rib eye roasts, cooking to internal temperatures of 37.8 or 48.9°C resulted in additional reductions of ca. 3.4 log CFU/g. For tenderized (nonintact) rib eye roasts, cooking to internal temperatures of 37.8 or 48.9°C resulted in additional reductions of ca. 3.1 or 3.4 log CFU/g, respectively. Pathogen populations remained relatively unchanged for intact roasts cooked to 37.8 or 48.9°C and for nonintact roasts cooked to 48.9°C when held at 60.0°C for up to 8 h. In contrast, pathogen populations increased ca. 2.0 log CFU/g in nonintact rib eye cooked to 37.8°C when held at 60.0°C for 8 h. Thus, cooking at low temperatures and extended holding at relatively low temperatures as evaluated herein may pose a food safety risk to consumers in terms of inadequate lethality and/or subsequent outgrowth of Salmonella, especially if nonintact rib eye is used in the preparation of prime rib, if on occasion appreciable populations of Salmonella are present in or on the meat, and/or if the meat is not cooked adequately throughout.
-
Ultrafiltration Membrane Module Virus Reduction at Different Fluxes, and with a Cut Fiber
NSF International evaluated The Dow Chemical Company SFD-2880 UF membrane module for MS2 reduction at four different fluxes, and also with and without a cut fiber, to compare MS2 log reduction under the different scenarios. All tests were conducted in accordance with the U.S. En...
-
Inactivation of norovirus surrogates on surfaces and raspberries by steam-ultrasound treatment.
Schultz, Anna Charlotte; Uhrbrand, Katrine; Nørrung, Birgit; Dalsgaard, Anders
2012-02-01
Human disease outbreaks caused by norovirus (NoV) following consumption of contaminated raspberries are an increasing problem. An efficient method to decontaminate the fragile raspberries and the equipment used for processing would be an important step in ensuring food safety. A potential surface treatment that combines pressurized steam and high-power ultrasound (steam-ultrasound) was assessed for its efficacy to inactivate human NoV surrogates: coliphage (MS2), feline calicivirus (FCV), and murine norovirus (MNV) inoculated on plastic surfaces and MS2 inoculated on fresh raspberries. The amounts of infectious virus and viral genomes were determined by plaque assay and reverse transcription-real time quantitative PCR (RT-qPCR), respectively. On plastic surfaces, an inactivation of >99.99% was obtained for both MS2 and FCV, corresponding to a 9.1-log and >4.8-log reduction after 1 or 3 s of treatment, respectively; while a 3.7-log (99.9%) reduction of MNV was reached after 3 s of treatment. However, on fresh raspberries only a 1-log reduction (∼89%) of MS2 could be achieved after 1 s of treatment, at which point damage to the texture of the fresh raspberries was evident. Increasing treatment time (0 to 3 s) resulted in negligible reductions of viral genome titers of MS2, FCV, and MNV on plastic surfaces as well as of MS2 inoculated on raspberries. Steam-ultrasound treatment in its current format does not appear to be an appropriate method to achieve sufficient decontamination of NoV-contaminated raspberries. However, steam-ultrasound may be used to decontaminate smooth surface areas and utensils in food production and processing environments.
-
Antimicrobial Activity of a Novel Vascular Access Film Dressing Containing Chlorhexidine Gluconate.
Wibaux, Anne; Thota, Priyaleela; Mastej, Jozef; Prince, Daniel L; Carty, Neal; Johnson, Peter
2015-01-01
Covering insertion sites with chlorhexidine impregnated dressings has been proven to be clinically effective in reducing catheter related blood stream infections (CR-BSI). Two chlorhexidine gluconate (CHG)-impregnated dressings are commercially available, a polyurethane foam disk and a film dressing containing a chlorhexidine gluconate-impregnated gel pad. While both have demonstrated efficacy in clinical settings, the major drawback of high cost and impaired IV insertion site visibility limits their usage. A new, simple film dressing containing CHG within its adhesive layer is now available. The objective of this study was to test the in vitro antimicrobial efficacy of the new dressing in comparison to the CHG-impregnated gel dressing. Quantitative aliquots of suspensions (concentration of 1.0x106 to 5.0x106 cfu/sample) of clinically relevant challenge organisms (Staphylococcus species, gram-negative bacilli, Candida albicans) were incubated in contact with the new CHG-containing film dressing, a placebo version of the same (negative control) and the commercially available CHG-impregnated gel dressing (positive control). Serial dilutions of the surviving organisms were quantified using the pour plate after 1, 3, 5, and 7 days of incubation in order to calculate an antimicrobial log10 reduction for each organism/dressing combination at each point in time. The new CHG-containing film dressing delivered greater than 5.0 log10 reduction throughout the 7 days on all aerobic gram-negative bacilli and Staphylococcus species tested. As of day 1 the CHG-containing film dressing provided greater than 5.0 log10 reduction on Candida albicans. There were no statistically significant differences in the log10 reduction between the two dressings tested. The new CHG-containing film dressing was found to be as effective as the chlorhexidine gluconate-impregnated gel dressing on clinically relevant microbes.
-
Udompijitkul, P; Daeschel, M A; Zhao, Y
2007-11-01
Antibacterial activity of electrolyzed oxidizing (EO) water prepared from 0.05% or 0.10% (w/v) sodium chloride (NaCl) solutions against indigenous bacteria associated with fresh strawberries (Fragaria x ananassa) was evaluated. The efficacy of EO water and sodium hypochlorite (NaOCl) solution in eliminating and controlling the growth of Listeria monocytogenes and Escherichia coli O157:H7 inoculated onto strawberries stored at 4 +/- 1 degrees C up to 15 d was investigated at exposure time of 1, 5, or 10 min. Posttreatment neutralization of fruit surfaces was also determined. More than 2 log(10) CFU/g reductions of aerobic mesophiles were obtained in fruits washed for 10 or 15 min in EO water prepared from 0.10% (w/v) NaCl solution. Bactericidal activity of the disinfectants against L. monocytogenes and E. coli O157:H7 was not affected by posttreatment neutralization, and increasing exposure time did not significantly increase the antibacterial efficacy against both pathogens. While washing fruit surfaces with distilled water resulted in 1.90 and 1.27 log(10) CFU/mL of rinse fluid reduction of L. monocytogenes and E. coli O157:H7, respectively, >/= 2.60 log(10) CFU/mL of rinse fluid reduction of L. monocytogenes and up to 2.35 and 3.12 log(10) CFU/mL of rinse fluid reduction of E. coli O157:H7 were observed on fruit surfaces washed with EO water and NaOCl solution, respectively. Listeria monocytogenes and E. coli O157:H7 populations decreased over storage regardless of prior treatment. However, EO water and aqueous NaOCl did not show higher antimicrobial potential than water treatment during refrigeration storage.
-
Vukosav, Petra; Mlakar, Marina; Tomišić, Vladislav
2012-10-01
A detailed study of iron (III)-citrate speciation in aqueous solution (θ=25°C, I(c)=0.7 mol L(-1)) was carried out by voltammetric and UV-vis spectrophotometric measurements and the obtained data were used for reconciled characterization of iron (III)-citrate complexes. Four different redox processes were registered in the voltammograms: at 0.1 V (pH=5.5) which corresponded to the reduction of iron(III)-monocitrate species (Fe:cit=1:1), at about -0.1 V (pH=5.5) that was related to the reduction of FeL(2)(5-), FeL(2)H(4-) and FeL(2)H(2)(3-) complexes, at -0.28 V (pH=5.5) which corresponded to the reduction of polynuclear iron(III)-citrate complex(es), and at -0.4V (pH=7.5) which was probably a consequence of Fe(cit)(2)(OH)(x) species reduction. Reversible redox process at -0.1 V allowed for the determination of iron(III)-citrate species and their stability constants by analyzing E(p) vs. pH and E(p) vs. [L(4-)] dependence. The UV-vis spectra recorded at varied pH revealed four different spectrally active species: FeLH (logβ=25.69), FeL(2)H(2)(3-) (log β=48.06), FeL(2)H(4-) (log β=44.60), and FeL(2)(5-) (log β=38.85). The stability constants obtained by spectrophotometry were in agreement with those determined electrochemically. The UV-vis spectra recorded at various citrate concentrations (pH=2.0) supported the results of spectrophotometric-potentiometric titration. Copyright © 2012 Elsevier B.V. All rights reserved.
-
Effectiveness of liquid soap and hand sanitizer against Norwalk virus on contaminated hands.
Liu, Pengbo; Yuen, Yvonne; Hsiao, Hui-Mien; Jaykus, Lee-Ann; Moe, Christine
2010-01-01
Disinfection is an essential measure for interrupting human norovirus (HuNoV) transmission, but it is difficult to evaluate the efficacy of disinfectants due to the absence of a practicable cell culture system for these viruses. The purpose of this study was to screen sodium hypochlorite and ethanol for efficacy against Norwalk virus (NV) and expand the studies to evaluate the efficacy of antibacterial liquid soap and alcohol-based hand sanitizer for the inactivation of NV on human finger pads. Samples were tested by real-time reverse transcription-quantitative PCR (RT-qPCR) both with and without a prior RNase treatment. In suspension assay, sodium hypochlorite concentrations of >or=160 ppm effectively eliminated RT-qPCR detection signal, while ethanol, regardless of concentration, was relatively ineffective, giving at most a 0.5 log(10) reduction in genomic copies of NV cDNA. Using the American Society for Testing and Materials (ASTM) standard finger pad method and a modification thereof (with rubbing), we observed the greatest reduction in genomic copies of NV cDNA with the antibacterial liquid soap treatment (0.67 to 1.20 log(10) reduction) and water rinse only (0.58 to 1.58 log(10) reduction). The alcohol-based hand sanitizer was relatively ineffective, reducing the genomic copies of NV cDNA by only 0.14 to 0.34 log(10) compared to baseline. Although the concentrations of genomic copies of NV cDNA were consistently lower on finger pad eluates pretreated with RNase compared to those without prior RNase treatment, these differences were not statistically significant. Despite the promise of alcohol-based sanitizers for the control of pathogen transmission, they may be relatively ineffective against the HuNoV, reinforcing the need to develop and evaluate new products against this important group of viruses.
-
de Abreu Corrêa, Adriana; Carratala, Anna; Barardi, Celia Regina Monte; Calvo, Miquel; Bofill-Mas, Sílvia
2012-01-01
Viruses excreted by humans affect the commercial and recreational use of coastal water. Shellfish produced in contaminated waters have been linked to many episodes and outbreaks of viral gastroenteritis, as well as other food-borne diseases worldwide. The risk can be reduced by appropriate treatment following harvesting and by depuration. The kinetics of inactivation of murine norovirus 1 and human adenovirus 2 in natural and artificial seawater by free available chlorine was studied by quantifying genomic copies (GC) using quantitative PCR and infectious viral particles (PFU). Human JC polyomavirus Mad4 kinetics were evaluated by quantitative PCR. DNase or RNase were used to eliminate free genomes and assess potential viral infectivity when molecular detection was performed. At 30 min of assay, human adenovirus 2 showed 2.6- and 2.7-log10 GC reductions and a 2.3- and 2.4-log10 PFU reductions in natural and artificial seawater, respectively, and infectious viral particles were still observed at the end of the assay. When DNase was used prior to the nucleic acid extraction the kinetic of inactivation obtained by quantitative PCR was statistically equivalent to the one observed by infectivity assays. For murine norovirus 1, 2.5, and 3.5-log10 GC reductions were observed in natural and artificial seawater, respectively, while no viruses remained infectious after 30 min of contact with chlorine. Regarding JC polyomavirus Mad4, 1.5- and 1.1-log10 GC reductions were observed after 30 min of contact time. No infectivity assays were conducted for this virus. The results obtained provide data that might be applicable to seawater used in shellfish depuration. PMID:22773637
-
Hassan, Ammar Ali; Skjerve, Eystein; Bergh, Claus; Nesbakken, Truls
2015-01-01
The main objective of the study was to assess the effect of steam vacuum pasteurisation on carcass contamination with focus on Escherichia coli, Enterobacteriaceae and total plate count (TPC). Additionally, the effect of an additional tryptone soy agar (TSA) step for resuscitation of Enterobacteriaceae after steam vacuum pasteurisation was investigated. Steam vacuum pasteurisation was applied at a temperature of >82°C for a duration of 10s on sheep and lamb carcasses (n=120). Samples were taken immediately: i) after trimming just before the use of steam vacuum and ii) after use of steam vacuum. Nordic Committee on Food Analysis methods were used in microbial analyses. The differences in log reduction were found significant for all of the three microorganisms (p<0.05). For TPC, the general reduction was a 0.65 log10 in the number of colony forming units (CFU) per cm(2). For E. coli, the median reduction effect on carcasses positive before decontamination was 1.1 log10 CFU/cm(2). A large variability of the effect was however found, with 50% of the figures ranging from a 0.24 to 1.62 log10 CFU/cm(2) reduction and a 10-90% range of 0-2.1. The number of positive carcasses with Enterobacteriaceae after steam vacuum pasteurisation was higher in samples where TSA+violet red bile glucose agar (VRBGA) was used compared to samples where only VRBGA was used (p<0.01). Steam vacuum pasteurisation was found efficient in reducing the total count, read as TPC, as well as the level of E. coli and Enterobacteriaceae. Copyright © 2014 Elsevier Ltd. All rights reserved.
-
CT Imaging, Data Reduction, and Visualization of Hardwood Logs
Daniel L. Schmoldt
1996-01-01
Computer tomography (CT) is a mathematical technique that, combined with noninvasive scanning such as x-ray imaging, has become a powerful tool to nondestructively test materials prior to use or to evaluate materials prior to processing. In the current context, hardwood lumber processing can benefit greatly by knowing what a log looks like prior to initial breakdown....
-
Monte Carlo simulation of the risk of contamination of apples with Escherichia coli O157:H7.
Duffy, Siobain; Schaffner, Donald W
2002-10-25
Quantitative descriptions of the frequency and extent of contamination of apple cider with pathogenic bacteria were obtained using literature data and computer simulation. Probability distributions were chosen to describe the risk of apple contamination by each suspected pathway. Tree-picked apples may be contaminated by birds infected with Escherichia coli O157:H7 when orchards were located near a sewage source (ocean or landfill). Dropped apples could become contaminated from either infected animal droppings or from contaminated manure if used as fertilizer. A risk assessment model was created in Analytica. The results of worst-case simulations revealed that 6-9 log CFU E. coli O157:H7 might be found on a harvest of 1000 dropped apples, while 3-4 log CFU contamination could be present on 1000 tree-picked apples. This model confirms that practices such as using dropped apples and using animal waste as fertilizer increase risk in the production of apple cider, and that pasteurization may not eliminate all contamination in juice from heavily contaminated fruit. Recently published FDA regulations for juices requiring a 5-log CFU/ml reduction of pathogenic bacteria in fresh juices should be a fail-safe measure for apples harvested in all but the worst-case scenarios.
-
March, Jordon K; Pratt, Michael D; Lowe, Chinn-Woan; Cohen, Marissa N; Satterfield, Benjamin A; Schaalje, Bruce; O'Neill, Kim L; Robison, Richard A
2015-01-01
This study investigated (1) the susceptibility of Bacillus anthracis (Ames strain), Bacillus subtilis (ATCC 19659), and Clostridium sporogenes (ATCC 3584) spores to commercially available peracetic acid (PAA)- and glutaraldehyde (GA)-based disinfectants, (2) the effects that heat-shocking spores after treatment with these disinfectants has on spore recovery, and (3) the timing of heat-shocking after disinfectant treatment that promotes the optimal recovery of spores deposited on carriers. Suspension tests were used to obtain inactivation kinetics for the disinfectants against three spore types. The effects of heat-shocking spores after disinfectant treatment were also determined. Generalized linear mixed models were used to estimate 6-log reduction times for each spore type, disinfectant, and heat treatment combination. Reduction times were compared statistically using the delta method. Carrier tests were performed according to AOAC Official Method 966.04 and a modified version that employed immediate heat-shocking after disinfectant treatment. Carrier test results were analyzed using Fisher's exact test. PAA-based disinfectants had significantly shorter 6-log reduction times than the GA-based disinfectant. Heat-shocking B. anthracis spores after PAA treatment resulted in significantly shorter 6-log reduction times. Conversely, heat-shocking B. subtilis spores after PAA treatment resulted in significantly longer 6-log reduction times. Significant interactions were also observed between spore type, disinfectant, and heat treatment combinations. Immediately heat-shocking spore carriers after disinfectant treatment produced greater spore recovery. Sporicidal activities of disinfectants were not consistent across spore species. The effects of heat-shocking spores after disinfectant treatment were dependent on both disinfectant and spore species. Caution must be used when extrapolating sporicidal data of disinfectants from one spore species to another. Heat-shocking provides a more accurate picture of spore survival for only some disinfectant/spore combinations. Collaborative studies should be conducted to further examine a revision of AOAC Official Method 966.04 relative to heat-shocking. PMID:26185111
-
Lee, JungEun; Zoh, KyungDuk; Ko, GwangPyo
2008-01-01
We studied inactivation and UV disinfection of murine norovirus (MNV) as a surrogate for human norovirus. We investigated the effects of different surface characteristics, temperatures, and NaCl concentrations on MNV survival using both a plaque assay and a real-time TaqMan reverse transcription (RT)-PCR assay. MNV survived more than 40 days on diaper material, on gauze, and in a stool suspension. Compared to inactivation at lower temperatures (−20 and 4°C), inactivation of MNV was greater at higher temperatures (18 and 30°C). On the surface of both gauze and diaper material, there was a <2-log10 reduction in the amount of infectious MNV in 40 days after incubation at both −20 and 4°C, compared to a >5-log10 reduction after incubation at 30°C in 24 days. MNV survived better in a stool suspension than on the surface of gauze or diaper material. A higher salt concentration increased the rate of inactivation of MNV. In 72 h, <0.3-, 1.5-, and 2.5-log10 reductions in the amount of infectious MNV occurred in distilled water and 0.5 and 1 M NaCl, respectively. We observed only minor reductions in the numbers of viral RNA copies as quantified by real-time TaqMan RT-PCR regardless of the temperature, the salt concentration, or the suspending medium. We also evaluated UV disinfection of infectious MNV with and without TiO2. The amount of MNV was significantly reduced by 254-nm UV with and without TiO2. When 25 mJ/cm2 UV was used, 3.3- and 3.6-log10 reductions in the amounts of infectious MNV occurred with and without TiO2, respectively. Our results demonstrate that MNV can persist in various environmental conditions and can be efficiently controlled by UV disinfection. PMID:18245239
-
Ravishankar, Sadhana; Zhu, Libin; Olsen, Carl W; McHugh, Tara H; Friedman, Mendel
2009-10-01
Apple-based edible films containing plant antimicrobials were evaluated for their activity against pathogenic bacteria on meat and poultry products. Salmonella enterica or E. coli O157:H7 (10(7) CFU/g) cultures were surface inoculated on chicken breasts and Listeria monocytogenes (10(6) CFU/g) on ham. The inoculated products were then wrapped with edible films containing 3 concentrations (0.5%, 1.5%, and 3%) of cinnamaldehyde or carvacrol. Following incubation at either 23 or 4 degrees C for 72 h, samples were stomached in buffered peptone water, diluted, and plated for enumeration of survivors. The antimicrobial films exhibited concentration-dependent activities against the pathogens tested. At 23 degrees C on chicken breasts, films with 3% antimicrobials showed the highest reductions (4.3 to 6.8 log CFU/g) of both S. enterica and E. coli O157:H7. Films with 1.5% and 0.5% antimicrobials showed 2.4 to 4.3 and 1.6 to 2.8 log reductions, respectively. At 4 degrees C, carvacrol exhibited greater activity than did cinnamaldehyde. Films with 3%, 1.5%, and 0.5% carvacrol reduced the bacterial populations by about 3, 1.6 to 3, and 0.8 to 1 logs, respectively. Films with 3% and 1.5% cinnamaldehyde induced 1.2 to 2.8 and 1.2 to 1.3 log reductions, respectively. For L. monocytogenes on ham, carvacrol films induced greater reductions than did cinnamaldehyde films at all concentrations tested. In general, the reduction of L. monocytogenes on ham at 23 degrees C was greater than at 4 degrees C. Added antimicrobials had minor effects on physical properties of the films. The results suggest that the food industry and consumers could use these films as wrappings to control surface contamination by foodborne pathogenic microorganisms.
-
Ceylan, Erdogan; McMahon, Wendy; Garren, Donna M
2017-09-01
Thermal inactivation of Listeria monocytogenes and Salmonella was evaluated on peas, spinach, broccoli, potatoes, and carrots that were treated with hot water and steam. One gram-positive bacterium, L. monocytogenes, and one gram-negative bacterium, Salmonella, were selected as pertinent human pathogens for evaluation. Samples were inoculated with a composite of five strains each of L. monocytogenes and Salmonella to achieve approximately 10 8 to 10 9 CFU/g. Inoculated samples were treated with hot water at 85 and 87.8°C and with steam at 85 and 96.7°C for up to 3.5 min. A greater than 5-log reduction of L. monocytogenes and Salmonella was achieved on all products within 0.5 min by hot water blanching at 85 and 87.8°C. Steam blanching at 85°C reduced Salmonella populations by greater than 5 log on spinach and peas within 2 min and on carrots and broccoli within 3.5 min. Populations of Salmonella were reduced by more than 5 log within 1 min on carrot, spinach, and broccoli and within 2 min on peas by steam blanching at 96.7°C. Steam blanching at 85°C reduced L. monocytogenes populations by more than 5 log on carrots and spinach within 2 min and on broccoli and peas within 3.5 min. L. monocytogenes populations were reduced more than 5 log within 1 min on carrot, spinach, peas and broccoli by steam blanching at 96.7°C. Longer treatment times and higher temperatures were required for steam-blanched samples than for samples blanched with hot water. Results suggest that hot water and steam blanching practices commonly used by the frozen vegetable industry will achieve the desired 5-log lethality of L. monocytogenes and Salmonella and will enhance microbiological safety prior to freezing.
-
Theaflavin-3,3′-Digallate and Lactic Acid Combinations Reduce Herpes Simplex Virus Infectivity
Xu, Weimin
2013-01-01
The present study examined the efficacy of using multiple mechanisms as part of a topical microbicide to inactivate herpes simplex virus (HSV) by combining theaflavin-3,3′-digallate (TF-3) and lactic acid (LA) over the pH range of 4.0 to 5.7 to mimic conditions in the female reproductive tract. Six clinical isolates of HSV-2 and two clinical isolates of HSV-1 were almost completely inactivated when TF-3 (100 μM) was present with LA over the pH range of 4.5 to 5.7, whereas four additional HSV-1 clinical isolates required TF-3 concentrations of 250 to 500 μM for comparable virus titer reduction. LA (1%) alone at pH 4.0 reduced the titers of laboratory and clinical isolates of HSV-1 and HSV-2 by ≥5 log10, but most LA-dependent antiviral activity was lost at a pH of ≥4.5. When HSV-1 and HSV-2 were incubated at pH 4.0 without LA virus titers were not reduced. At pH 4.0, HSV-1 and HSV-2 titers were reduced 5 log10 in 20 min by LA alone. TF-3 reduced HSV-2 titers by 5 log10 in 20 to 30 min at pH 4.5, whereas HSV-1 required 60 min for comparable inactivation. Mixtures of TF-3 and LA stored at 37°C for 1 month at pH 4.0 to 5.7 maintained antiviral activity. Semen, but not cervical vaginal fluid, decreased LA-dependent antiviral activity at pH 4.0, but adding TF-3 to the mixture reduced HSV titers by 4 to 5 log10. These results indicate that a combination microbicide containing TF-3 and LA could reduce HSV transmission. PMID:23716050
-
A method of estimating log weights.
Charles N. Mann; Hilton H. Lysons
1972-01-01
This paper presents a practical method of estimating the weights of logs before they are yarded. Knowledge of log weights is required to achieve optimum loading of modern yarding equipment. Truckloads of logs are weighed and measured to obtain a local density index (pounds per cubic foot) for a species of logs. The density index is then used to estimate the weights of...
-
1. GENERAL VIEW OF LOG POND AND BOOM FOR UNLOADING ...
1. GENERAL VIEW OF LOG POND AND BOOM FOR UNLOADING CEDAR LOGS FROM TRUCKS AT LOG DUMP, ADJACENT TO MILL; TRUCKS FORMERLY USED TRIP STAKES, THOUGH FOR SAFER HANDLING OF LOGS WELDED STAKES ARE NOW REQUIRED; AS A RESULT LOADING IS NOW DONE WITH A CRANE - Lester Shingle Mill, 1602 North Eighteenth Street, Sweet Home, Linn County, OR
-
Shah, Manoj K; Asa, Gladys; Sherwood, Julie; Graber, Kari; Bergholz, Teresa M
2017-03-06
Low moisture foods such as nuts, spices, and seeds have been implicated in several outbreaks due to Salmonella or E. coli O157:H7 contamination. Such foods may be consumed raw, and can be used as ingredients in other food products. While numerous thermal inactivation studies have been conducted for Salmonella on nuts, studies on other seeds and grains are minimal. Product water activity can influence the thermal resistance of pathogens, where thermal resistance increases as water activity decreases, leading to a requirement for higher temperatures and longer exposure times to achieve significant reduction of pathogen numbers. Vacuum steam pasteurization uses steam under vacuum, which can be operated at temperatures above and below 100°C. The objective of this study was to determine the efficacy of vacuum steam pasteurization for inactivation of pathogens on whole flaxseed, quinoa, sunflower kernels, milled flaxseed and whole black peppercorns. The use of E. faecium as a potential surrogate for Salmonella and E. coli O157:H7 in vacuum steam pasteurization was also evaluated. Pasteurization for 1min at 75°C yielded average log reductions of 5.48±1.22, 5.71±0.40 and 5.23±0.61 on flaxseed, 4.29±0.92, 5.89±0.26 and 2.39±0.83 on quinoa, and 4.01±0.74, 5.40±0.83 and 2.99±0.92 on sunflower kernels for Salmonella PT 30, E. coli O157:H7 and E. faecium, respectively. Similarly, on milled flaxseed and black peppercorns average log reductions of 3.02±0.79 and 6.10±0.64CFU/g were observed for Salmonella PT 30 after 1min of treatment at 75°C but, on average, >6.0 log reductions were observed after pasteurization at 85°C. Our data demonstrate that vacuum steam pasteurization can be effectively used to reduce pathogens on these low moisture foods at temperature as low as 75 and 85°C, and that E. faecium may be used as a potential surrogate for Salmonella PT 30 and E. coli O157:H7. Copyright © 2017 Elsevier B.V. All rights reserved.
-
Chaves, B D; Han, I Y; Dawson, P L; Northcutt, J K
2011-12-01
Escherichia coli and Salmonella spp. are ubiquitous in the poultry production environment, and hence, their transmission to poultry products is of concern. Industry has widely used freezing as a strategy to halt pathogen growth, and more recently, crust freezing has been suggested as a means to improve mechanical operations, quality, and safety of poultry products. The purpose of this study was to evaluate the effect of crust freezing on the survival of Escherichia coli and Salmonella Typhimurium that were artificially inoculated on the surface of raw poultry products with or without adhering skin. Ampicillin-resistant (AR) E. coli JM 109 and nalidixic acid-resistant (NAR) Salmonella Typhimurium were used in the experiments. A set of cultures was subjected to cold-shock stress by storage at 4°C for 10 d. After being either cold-shocked or non-cold-shocked, commercial chicken breasts without skin and chicken thighs with skin were inoculated in separate experiments with each bacterium. Samples were crust frozen at -85°C for 20 min or completely frozen at -85°C for 60 min. The E. coli and Salmonella Typhimurium were recovered on appropriate selective and nonselective media containing the corresponding antibiotic. Log reductions and extent of injury were calculated and treatments were compared using ANOVA. No significant differences were observed in the reduction of cold-shocked or non-cold-shocked bacteria on products with or without skin that were crust or completely frozen. The average reduction for E. coli was 0.15 log(10) cfu/mL of rinse, and for Salmonella Typhimurium 0.10 log(10) cfu/mL of rinse; therefore, none of the final reductions were greater than the desired target (1 log). Bacterial cell injury was not significantly different (P > 0.05) among any of the treatments. Data showed no practical significance for initial reduction of these pathogens from crust freezing and thus, this technology should not be considered as a strategy for the reduction of E. coli and Salmonella Typhimurium on poultry.
-
Barker, S Fiona; Packer, Michael; Scales, Peter J; Gray, Stephen; Snape, Ian; Hamilton, Andrew J
2013-09-01
Small, remote communities often have limited access to energy and water. Direct potable reuse of treated wastewater has recently gained attention as a potential solution for water-stressed regions, but requires further evaluation specific to small communities. The required pathogen reduction needed for safe implementation of direct potable reuse of treated sewage is an important consideration but these are typically quantified for larger communities and cities. A quantitative microbial risk assessment (QMRA) was conducted, using norovirus, giardia and Campylobacter as reference pathogens, to determine the level of treatment required to meet the tolerable annual disease burden of 10(-6) DALYs per person per year, using Davis Station in Antarctica as an example of a small remote community. Two scenarios were compared: published municipal sewage pathogen loads and estimated pathogen loads during a gastroenteritis outbreak. For the municipal sewage scenario, estimated required log10 reductions were 6.9, 8.0 and 7.4 for norovirus, giardia and Campylobacter respectively, while for the outbreak scenario the values were 12.1, 10.4 and 12.3 (95th percentiles). Pathogen concentrations are higher under outbreak conditions as a function of the relatively greater degree of contact between community members in a small population, compared with interactions in a large city, resulting in a higher proportion of the population being at risk of infection and illness. While the estimates of outbreak conditions may overestimate sewage concentration to some degree, the results suggest that additional treatment barriers would be required to achieve regulatory compliance for safe drinking water in small communities. Copyright © 2013 Elsevier B.V. All rights reserved.
-
2016-01-01
The pandemic of hospital-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has declined, but the evolution of strains with enhanced virulence and toxins and the increase of community-associated infections are still a threat. In previous studies, 107 MRSA bacteria applied as simulated droplet contamination were killed on copper and brass surfaces within 90 min. However, contamination of surfaces is often via finger tips and dries rapidly, and it may be overlooked by cleaning regimes (unlike visible droplets). In this new study, a 5-log reduction of a hardy epidemic strain of MRSA (epidemic methicillin-resistant S. aureus 16 [EMRSA-16]) was observed following 10 min of contact with copper, and a 4-log reduction was observed on copper nickel and cartridge brass alloys in 15 min. A methicillin-sensitive S. aureus (MSSA) strain from an osteomyelitis patient was killed on copper surfaces in 15 min, and 4-log and 3-log reductions occurred within 20 min of contact with copper nickel and cartridge brass, respectively. Bacterial respiration was compromised on copper surfaces, and superoxide was generated as part of the killing mechanism. In addition, destruction of genomic DNA occurs on copper and brass surfaces, allaying concerns about horizontal gene transfer and copper resistance. Incorporation of copper alloy biocidal surfaces may help to reduce the spread of this dangerous pathogen. PMID:26826226
-
Macinga, David R.; Beausoleil, Christopher M.; Campbell, Esther; Mulberry, Gayle; Brady, Ann; Edmonds, Sarah L.; Arbogast, James W.
2011-01-01
A novel method has been developed for the evaluation of alcohol-based hand rubs (ABHR) that employs a hand contamination procedure that more closely simulates the in-use conditions of ABHR. Hands of human subjects were contaminated with 0.2 ml of a concentrated suspension of Serratia marcescens (ATCC 14756) to achieve baseline contamination between 8 and 9 log10 CFU/hand while allowing product to be applied to dry hands with minimal soil load. Evaluation of 1.5 ml of an ABHR gel containing 62% ethanol produced log10 reductions of 2.66 ± 0.96, 2.40 ± 0.50, 2.41 ± 0.61, and 2.33 ± 0.49 (means ± standard deviations) after 1, 3, 7, and 10 successive contamination/product application cycles. In a study comparing this low-volume contamination (LVC) method to ASTM E1174, product dry times were more realistic and log10 reductions achieved by the ABHR were significantly greater when LVC was employed (P < 0.05). These results indicate that a novel low-volume hand contamination procedure, which more closely represents ABHR use conditions, provides more realistic estimates of in-use ABHR efficacies. Based on the LVC method, log10 reductions produced by ABHR were strongly dependent on the test product application volume (P < 0.0001) but were not influenced by the alcohol concentration when it was within the range of 62 to 85% (P = 0.378). PMID:22003004
-
A meta-analysis of the published literature on the effectiveness of antimicrobial soaps.
Montville, Rebecca; Schaffner, Donald W
2011-11-01
The goal of this research was to conduct a systematic quantitative analysis of the existing data in the literature in order to determine if there is a difference between antimicrobial and nonantimicrobial soaps and to identify the methodological factors that might affect this difference. Data on hand washing efficacy and experimental conditions (sample size, wash duration, soap quantity, challenge organism, inoculum size, and neutralization method) from published studies were compiled and transferred to a relational database. A total of 25 publications, containing 374 observations, met the study selection criteria. The majority of the studies included fewer than 15 observations with each treatment and included a direct comparison between nonantimicrobial soap and antimicrobial soap. Although differences in efficacy between antimicrobial and nonantimicrobial soap were small (∼0.5-log CFU reduction difference), antimicrobial soap produced consistently statistically significantly greater reductions. This difference was true for any of the antimicrobial compounds investigated where n was >20 (chlorhexidine gluconate, iodophor, triclosan, or povidone). Average log reductions were statistically significantly greater (∼2 log CFU) when either gram-positive or gram-negative transient organisms were deliberately added to hands compared with experiments done with resident hand flora (∼0.5 log CFU). Our findings support the importance of using a high initial inoculum on the hands, well above the detection limit. The inherent variability in hand washing seen in the published literature underscores the importance of using a sufficiently large sample size to detect differences when they occur.
-
Park, S Y; Jung, S-J; Kang, I; Ha, S-D
2018-05-01
This study investigated bactericidal activity of 0.05 to 0.50% calcium oxide (CaO) against planktonic cells in tryptic soy broth (TSB) and biofilms of Listeria monocytogenes on eggshell surfaces. The bactericidal activity of CaO against planktonic cells and biofilms of L. monocytogens significantly (P < 0.05) increased log reductions with increasing concentrations of CaO. Exposure to 0.05 to 0.50% CaO for one min reduced planktonic cells in TSB cell suspensions by 0.47 to 3.86 log10CFU/mL and biofilm cells on the shell surfaces by 0.14 to 2.32 log10CFU/cm2. The Hunter colors of eggshells ("L" for lightness, "a" for redness, and "b" for yellowness), shell thickness (puncture force), and sensory quality (egg taste and yolk color) were not changed by 0.05 to 0.50% CaO treatment. The nonlinear Weibull model was used to calculate CR = 3 values as the CaO concentration of 3 log (99.9%) reduction for planktonic cells (R2 = 0.96, RMSE = 0.26) and biofilms (R2 = 0.95, RMSE = 0.18) of L. monocytogens. The CR = 3 value, 0.31% CaO for planktonic cells, was significantly (P < 0.05) lower than 0.57% CaO for biofilms. CaO could be an alternative disinfectant to reduce planktonic cells and biofilms L. monocytogenes on eggshell surface in egg processing plants.
-
Palanichamy, A; Jayas, D S; Holley, R A
2008-01-01
The Canadian Food Inspection Agency required the meat industry to ensure Escherichia coli O157:H7 does not survive (experiences > or = 5 log CFU/g reduction) in dry fermented sausage (salami) during processing after a series of foodborne illness outbreaks resulting from this pathogenic bacterium occurred. The industry is in need of an effective technique like predictive modeling for estimating bacterial viability, because traditional microbiological enumeration is a time-consuming and laborious method. The accuracy and speed of artificial neural networks (ANNs) for this purpose is an attractive alternative (developed from predictive microbiology), especially for on-line processing in industry. Data from a study of interactive effects of different levels of pH, water activity, and the concentrations of allyl isothiocyanate at various times during sausage manufacture in reducing numbers of E. coli O157:H7 were collected. Data were used to develop predictive models using a general regression neural network (GRNN), a form of ANN, and a statistical linear polynomial regression technique. Both models were compared for their predictive error, using various statistical indices. GRNN predictions for training and test data sets had less serious errors when compared with the statistical model predictions. GRNN models were better and slightly better for training and test sets, respectively, than was the statistical model. Also, GRNN accurately predicted the level of allyl isothiocyanate required, ensuring a 5-log reduction, when an appropriate production set was created by interpolation. Because they are simple to generate, fast, and accurate, ANN models may be of value for industrial use in dry fermented sausage manufacture to reduce the hazard associated with E. coli O157:H7 in fresh beef and permit production of consistently safe products from this raw material.
-
Error Reduction Methods for Integrated-path Differential-absorption Lidar Measurements
NASA Technical Reports Server (NTRS)
Chen, Jeffrey R.; Numata, Kenji; Wu, Stewart T.
2012-01-01
We report new modeling and error reduction methods for differential-absorption optical-depth (DAOD) measurements of atmospheric constituents using direct-detection integrated-path differential-absorption lidars. Errors from laser frequency noise are quantified in terms of the line center fluctuation and spectral line shape of the laser pulses, revealing relationships verified experimentally. A significant DAOD bias is removed by introducing a correction factor. Errors from surface height and reflectance variations can be reduced to tolerable levels by incorporating altimetry knowledge and "log after averaging", or by pointing the laser and receiver to a fixed surface spot during each wavelength cycle to shorten the time of "averaging before log".
-
Bover-Cid, S; Belletti, N; Aymerich, T; Garriga, M
2017-01-01
This work aimed to quantify the impact of a w and fat content of dry-cured ham on the Log reduction of Salmonella enterica by high pressure (HP). Dry-cured ham with adjusted a w (0.86-0.96) and fat content (10-50%) was inoculated with S. enterica and pressurised (347-852MPa, 5min/15°C), following a Central Composite Design. Polynomial regression indicated a significant impact of pressure and a w on S. enterica HP-lethality. By lowering a w a clear piezoprotection was observed. At low a w (0.88) the S. enterica reduction was little affected by increasing pressure (e.g. 2.3 to 3.2 Logs at 450 to 750MPa, respectively). At the highest a w the estimated inactivation ranged from 3.3 to 8.9 Logs at 450 to 750MPa, respectively. No significant piezoprotective effect on S. enterica was recorded by the fat content. The relevance of food characteristics on the HP-lethality of S. enterica indicate the need to validate the HP effectiveness on the specific product. Copyright © 2016 Elsevier Ltd. All rights reserved.
-
Users guide for FRCS: fuel reduction cost simulator software.
Roger D. Fight; Bruce R. Hartsough; Peter Noordijk
2006-01-01
The Fuel Reduction Cost Simulator (FRCS) spreadsheet application is public domain software used to estimate costs for fuel reduction treatments involving removal of trees of mixed sizes in the form of whole trees, logs, or chips from a forest. Equipment production rates were developed from existing studies. Equipment operating cost rates are from December 2002 prices...
-
40 CFR 141.400 - General requirements and applicability.
Code of Federal Regulations, 2010 CFR
2010-07-01
... requirements and applicability. (a) Scope of this subpart. The requirements of this subpart S constitute... systems that do not treat all of their ground water to at least 99.99 percent (4-log) treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal...
-
Ditommaso, Savina; Giacomuzzi, Monica; Ricciardi, Elisa; Zotti, Carla M
2016-07-22
This study was designed to examine the in vitro bactericidal activity of hydrogen peroxide against Legionella. We tested hydrogen peroxide (Peroxy Ag⁺) at 600 ppm to evaluate Legionella survival in a simulated dental treatment water system equipped with Water Hygienization Equipment (W.H.E.) device that was artificially contaminated. When Legionella pneumophila serogroup (sg) 1 was exposed to Peroxy Ag⁺ for 60 min we obtained a two decimal log reduction. High antimicrobial efficacy was obtained with extended periods of exposure: four decimal log reduction at 75 min and five decimal log reduction at 15 h of exposure. Involving a simulation device (Peroxy Ag⁺ is flushed into the simulation dental unit waterlines (DUWL)) we obtained an average reduction of 85% of Legionella load. The product is effective in reducing the number of Legionella cells after 75 min of contact time (99.997%) in the simulator device under test conditions. The Peroxy Ag⁺ treatment is safe for continuous use in the dental water supply system (i.e., it is safe for patient contact), so it could be used as a preventive option, and it may be useful in long-term treatments, alone or coupled with a daily or periodic shock treatment.
-
Kang, Mi-Sun; Lim, Hae-Soon; Oh, Jong-Suk; Lim, You-Jin; Wuertz-Kozak, Karin; Harro, Janette M; Shirtliff, Mark E; Achermann, Yvonne
2017-03-01
The increasing prevalence of methicillin-resistant Staphylococcus aureus has become a major public health threat. While lactobacilli were recently found useful in combating various pathogens, limited data exist on their therapeutic potential for S. aureus infections. The aim of this study was to determine whether Lactobacillus salivarius was able to produce bactericidal activities against S. aureus and to determine whether the inhibition was due to a generalized reduction in pH or due to secreted Lactobacillus product(s). We found an 8.6-log10 reduction of planktonic and a 6.3-log10 reduction of biofilm S. aureus. In contrast, the previously described anti-staphylococcal effects of L. fermentum only caused a 4.0-log10 reduction in planktonic S. aureus cells, with no effect on biofilm S. aureus cells. Killing of S. aureus was partially pH dependent, but independent of nutrient depletion. Cell-free supernatant that was pH neutralized and heat inactivated or proteinase K treated had significantly reduced killing of L. salivarius than with pH-neutralized supernatant alone. Proteomic analysis of the L. salivarius secretome identified a total of five secreted proteins including a LysM-containing peptidoglycan binding protein and a protein peptidase M23B. These proteins may represent potential novel anti-staphylococcal agents that could be effective against S. aureus biofilms. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
-
Lumber or chips? A comparison of small-log utilization alternatives
Barney Dowdle; Robert Bain
1961-01-01
A sawmill in the Northeast commonly receives a number of small low-quality logs. They may be among logs purchased from independent loggers, or timber-sale specifications may require that the sawmill take them. Some mill operators confronted with logs of this kind consider handling them as part of the cost of obtaining their log supply. Others may feel that, since the...
-
Musavian, Hanieh S; Butt, Tariq M; Larsen, Annette Baltzer; Krebs, Niels
2015-02-01
Food contact surfaces require rigorous sanitation procedures for decontamination, although these methods very often fail to efficiently clean and disinfect surfaces that are visibly contaminated with food residues and possible biofilms. In this study, the results of a short treatment (1 to 2 s) of combined steam (95°C) and ultrasound (SonoSteam) of industrial fish and meat transportation boxes and live-chicken transportation crates naturally contaminated with food and fecal residues were investigated. Aerobic counts of 5.0 to 6.0 log CFU/24 cm(2) and an Enterobacteriaceae spp. level of 2.0 CFU/24 cm(2) were found on the surfaces prior to the treatment. After 1 s of treatment, the aerobic counts were significantly (P < 0.0001) reduced, and within 2 s, reductions below the detection limit (<10 CFU) were reached. Enterobacteriaceae spp. were reduced to a level below the detection limit with only 1 s of treatment. Two seconds of steam-ultrasound treatment was also applied on two different types of plastic modular conveyor belts with hinge pins and one type of flat flexible rubber belt, all visibly contaminated with food residues. The aerobic counts of 3.0 to 5.0 CFU/50 cm(2) were significantly (P < 0.05) reduced, while Enterobacteriaceae spp. were reduced to a level below the detection limit. Industrial meat knives were contaminated with aerobic counts of 6.0 log CFU/5 cm(2) on the handle and 5.2 log CFU/14 cm(2) on the steel. The level of Enterobacteriaceae spp. contamination was approximately 2.5 log CFU on the handle and steel. Two seconds of steam-ultrasound treatment reduced the aerobic counts and Enterobacteriaceae spp. to levels below the detection limit on both handle and steel. This study shows that the steam-ultrasound treatment may be an effective replacement for disinfection processes and that it can be used for continuous disinfection at fast process lines. However, the treatment may not be able to replace efficient cleaning processes used to remove high loads of debris.
-
Kundu, Devapriya; Gill, Alexander; Lui, Chenyuan; Goswami, Namita; Holley, Richard
2014-01-01
This study determined the extent that irradiation of fresh beef surfaces with an absorbed dose of 1 kGy electron (e-) beam irradiation might reduce the viability of mixtures of O157 and non-O157 verotoxigenic Escherichia coli (VTEC) and Salmonella. These were grouped together based on similar resistances to irradiation and inoculated on beef surfaces (outside flat and inside round, top and bottom muscle cuts), and then e-beam irradiated. Salmonella serovars were most resistant to 1 kGy treatment, showing a reduction of ≤1.9 log CFU/g. This treatment reduced the viability of two groups of non-O157 E. coli mixtures by ≤4.5 and ≤3.9 log CFU/g. Log reductions of ≤4.0 log CFU/g were observed for E. coli O157:H7 cocktails. Since under normal processing conditions the levels of these pathogens on beef carcasses would be lower than the lethality caused by the treatment used, irradiation at 1 kGy would be expected to eliminate the hazard represented by VTEC E. coli. © 2013.
-
Jung, Soo-Jin; Park, Shin Young; Kim, Seh Eun; Kang, Ike; Park, Jiyong; Lee, Jungwon; Kim, Chang-Min; Chung, Myung-Sub; Ha, Sang-Do
2017-07-01
The aim of this study was to evaluate the bactericidal effect of calcium oxide (CaO) against Pseudomonas aeruginosa biofilms on quail eggshells and major egg contacting surfaces (stainless steel, plastic, and rubber). The samples were subjected to CaO treatments (0%, 0.01%, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, and 0.30%) for 1 min. All the CaO treatments significantly reduced P. aeruginosa biofilms on all tested surfaces as compared to controls. In comparison of biofilm stability, the strongest and most resistant biofilm was formed on eggshell against the CaO treatment, followed by rubber, stainless steel, and plastic. In evaluation of bactericidal effect, the largest reduction (3.16 log CFU) was observed in plastic even at the lowest concentration of CaO (0.01%), whereas the least reduction was found in eggshells, regardless of CaO concentration. In addition, stainless steel showed a significant reduction in biofilm formation at all concentrations except 0.10% to 0.15% CaO. At 0.30% CaO, the reduction of P. aeruginosa in biofilms on stainless steel, plastic, rubber, and eggshell were 5.48, 6.37, 4.87, and 3.14 log CFU/cm 2 (CFU/egg), respectively. Biofilm reduction after CaO treatment was also observed by field emission scanning electron microscopy (FE-SEM). Based on the FE-SEM images, we observed that P. aeruginosa biofilms formed compact aggregations on eggshell surfaces with CaO treatments up to 0.30%. More specifically, a 0.20% CaO treatment resulted in the reductions of 3 to 6 log CFU in all materials. © 2017 Institute of Food Technologists®.
-
Yokomizo, Tomo; Kai, Takako; Miura, Morikazu; Ohto, Hitoshi
2015-02-01
Leukofiltration of blood components is currently implemented worldwide as a precautionary measure against white blood cell-associated adverse effects and the potential transmission of variant Creutzfeldt-Jakob disease (vCJD). A newly developed bifunctional filter (Sepacell Prima, Asahi Kasei Medical) was assessed for prion removal, leukoreduction (LR), and whether the filter significantly affected red blood cells (RBCs). Sepacell Prima's postfiltration effects on RBCs, including hemolysis, complement activation, and RBC chemistry, were compared with those of a conventional LR filter (Sepacell Pure RC). Prion removal was measured by Western blot after spiking RBCs with microsomal fractions derived from scrapie-infected hamster brain homogenate. Serially diluted exogenous prion solutions (0.05 mL), with or without filtration, were injected intracerebrally into Golden Syrian hamsters. LR efficiency of 4.44 log with the Sepacell Prima was comparable to 4.11 log with the conventional LR filter. There were no significant differences between the two filters in hemoglobin loss, hemolysis, complement activation, and RBC biomarkers. In vitro reduction of exogenously spiked prions by the filter exceeded 3 log. The titer, 6.63 (log ID50 /mL), of prefiltration infectivity of healthy hamsters was reduced to 2.52 (log ID50 /mL) after filtration. The reduction factor was calculated as 4.20 (log ID50 ). With confirmed removal efficacy for exogenous prion protein, this new bifunctional prion and LR filter should reduce the residual risk of vCJD transmission through blood transfusion without adding complexity to component processing. © 2014 AABB.
-
Woody debris volume depletion through decay: implications for biomass and carbon accounting
Fraver, Shawn; Milo, Amy M.; Bradford, John B.; D'Amato, Anthony W.; Kenefic, Laura; Palik, Brian J.; Woodall, Christopher W.; Brissette, John
2013-01-01
Woody debris decay rates have recently received much attention because of the need to quantify temporal changes in forest carbon stocks. Published decay rates, available for many species, are commonly used to characterize deadwood biomass and carbon depletion. However, decay rates are often derived from reductions in wood density through time, which when used to model biomass and carbon depletion are known to underestimate rate loss because they fail to account for volume reduction (changes in log shape) as decay progresses. We present a method for estimating changes in log volume through time and illustrate the method using a chronosequence approach. The method is based on the observation, confirmed herein, that decaying logs have a collapse ratio (cross-sectional height/width) that can serve as a surrogate for the volume remaining. Combining the resulting volume loss with concurrent changes in wood density from the same logs then allowed us to quantify biomass and carbon depletion for three study species. Results show that volume, density, and biomass follow distinct depletion curves during decomposition. Volume showed an initial lag period (log dimensions remained unchanged), even while wood density was being reduced. However, once volume depletion began, biomass loss (the product of density and volume depletion) occurred much more rapidly than density alone. At the temporal limit of our data, the proportion of the biomass remaining was roughly half that of the density remaining. Accounting for log volume depletion, as demonstrated in this study, provides a comprehensive characterization of deadwood decomposition, thereby improving biomass-loss and carbon-accounting models.
-
DOE Office of Scientific and Technical Information (OSTI.GOV)
Khan, Muhammad Saiful Islam; Lee, Eun-Jung; Kim, Yun-Ji, E-mail: yunji@kfri.re.kr
A submerged dielectric barrier discharge plasma reactor (underwater DBD) has been used on Escherichia coli O157:H7 (ATCC 35150). Plasma treatment was carried out using clean dry air gas to investigate the individual effects of the radicals produced by underwater DBD on an E. coli O157:H7 suspension (8.0 log CFU/ml). E. coli O157:H7 was reduced by 6.0 log CFU/ml for 2 min of underwater DBD plasma treatment. Optical Emission Spectra (OES) shows that OH and NO (α, β) radicals, generated by underwater DBD along with ozone gas. E. coli O157:H7 were reduced by 2.3 log CFU/ml for 10 min of underwatermore » DBD plasma treatment with the terephthalic acid (TA) OH radical scavenger solution, which is significantly lower (3.7 log CFU/ml) than the result obtained without using the OH radical scavenger. A maximum of 1.5 ppm of ozone gas was produced during the discharge of underwater DBD, and the obtained reduction difference in E.coli O157:H7 in presence and in absence of ozone gas was 1.68 log CFU/ml. The remainder of the 0.62 log CFU/ml reduction might be due to the effect of the NO (α, β) radicals or due to the combined effect of all the radicals produced by underwater DBD. A small amount of hydrogen peroxide was also generated but does not play any role in E. coli O157:H7 inactivation.« less
-
NASA Astrophysics Data System (ADS)
Khan, Muhammad Saiful Islam; Lee, Eun-Jung; Kim, Yun-Ji
2015-10-01
A submerged dielectric barrier discharge plasma reactor (underwater DBD) has been used on Escherichia coli O157:H7 (ATCC 35150). Plasma treatment was carried out using clean dry air gas to investigate the individual effects of the radicals produced by underwater DBD on an E. coli O157:H7 suspension (8.0 log CFU/ml). E. coli O157:H7 was reduced by 6.0 log CFU/ml for 2 min of underwater DBD plasma treatment. Optical Emission Spectra (OES) shows that OH and NO (α, β) radicals, generated by underwater DBD along with ozone gas. E. coli O157:H7 were reduced by 2.3 log CFU/ml for 10 min of underwater DBD plasma treatment with the terephthalic acid (TA) OH radical scavenger solution, which is significantly lower (3.7 log CFU/ml) than the result obtained without using the OH radical scavenger. A maximum of 1.5 ppm of ozone gas was produced during the discharge of underwater DBD, and the obtained reduction difference in E.coli O157:H7 in presence and in absence of ozone gas was 1.68 log CFU/ml. The remainder of the 0.62 log CFU/ml reduction might be due to the effect of the NO (α, β) radicals or due to the combined effect of all the radicals produced by underwater DBD. A small amount of hydrogen peroxide was also generated but does not play any role in E. coli O157:H7 inactivation.
-
Evaluation of sanitizers for inactivating Salmonella on in-shell pecans and pecan nutmeats.
Beuchat, Larry R; Mann, David A; Alali, Walid Q
2012-11-01
Chlorine, organic acids, and water extracts of inedible pecan components were tested for effectiveness in killing Salmonella on pecans. In-shell pecans and nutmeats (U.S. Department of Agriculture medium pieces) were immersion inoculated with a mixture of five Salmonella serotypes, dried to 3.7% moisture, and stored at 4°C for 3 to 6 weeks. In-shell nuts were immersed in chlorinated water (200, 400, and 1,000 μg/ml), lactic acid (0.5, 1, and 2%), and levulinic acid (0.5, 1, and 2%) with and without 0.05% sodium dodecyl sulfate (SDS), and a mixed peroxyacid sanitizer (Tsunami 200, 40 μg/ml) for up to 20 min at 21°C. The rate of reduction of free chlorine in conditioning water decreased as the ratio of in-shell nuts/water was increased. The rate of reduction was more rapid when nuts were not precleaned before treatment. The initial population of Salmonella on in-shell nuts (5.9 to 6.3 log CFU/g) was reduced by 2.8 log CFU/g after treating with chlorinated water (1,000 μg/ml). Treatment with 2% lactic acid plus SDS or 2% levulinic acid plus SDS reduced the pathogen by 3.7 and 3.4 log CFU/g, respectively. Lactic and levulinic acids (2%) without SDS were less effective (3.3- and 2.1-log CFU/g reductions, respectively) than acids with SDS. Treatment with Tsunami 200 resulted in a 2.4-log CFU/g reduction. In-shell nuts and nutmeats were immersed in water extracts of ground pecan shucks (hulls), shells, a mixture of shells and pith, and pith. The general order of lethality of extracts to Salmonella was shuck < shell-pith ≤ shell ≤ pith < chlorine (400 μg/ml) and shuck < shell ≤ pith = shell-pith < chlorine (400 μg/ml). Results emphasize the importance of removing soil and dust on in-shell pecans before conditioning in chlorinated water and the need for sanitizers with increased effectiveness in killing Salmonella on pecans.
-
Fett, William F; Cooke, Peter H
2003-07-01
Alfalfa sprouts contaminated with the bacterial pathogens Escherichia coli O157:H7 and Salmonella have been the source of numerous outbreaks of foodborne illness in the United States and in other countries. The seed used for sprouting appears to be the primary source of these pathogens. The aim of this study was to determine whether the efficacy of commercial citrus-related products for sanitizing sprouting seed is similar to that of high levels of chlorine. Five products (Citrex, Pangermex, Citricidal, Citrobio, and Environné) were tested at concentrations of up to 20,000 ppm in sterile tap water and compared with buffered chlorine (at 16,000 ppm). Alfalfa seeds were inoculated with four-strain cocktails of Salmonella and E. coli O157:H7 to give final initial concentrations of ca. 9.0 and 7.0 CFU/g, respectively. Treatments (10 min) with Citrex, Pangermex, and Citricidal at 20,000 ppm and chlorine at 16,000 ppm produced similar log reductions for alfalfa seed inoculated with four-strain cocktails of E. coli O157:H7 and Salmonella (3.42 to 3.46 log CFU/g and 3.56 to 3.74 log CFU/g, respectively), and all four treatments were significantly (P<0.05) more effective than the control treatment (a buffer wash). Citrobio at 20,000 ppm was as effective as the other three products and chlorine against Salmonella but not against E. coli O157:H7. Environné was not more effective (producing reductions of 2.2 to 2.9 log CFU/g) than the control treatment (which produced reductions of 2.1 to 2.3 log CFU/g) against either pathogen. None of the treatments reduced seed germination. In vitro assays, as well as transmission electron microscopy, confirmed the antibacterial nature of the products that were effective against the two pathogens and indicated that they were bactericidal. When used at 20,000 ppm, the effective citrus-related products may be viable alternatives to chlorine for the sanitization of sprouting seed pending regulatory approval.
-
Electronic Warfare M-on-N Digital Simulation Logging Requirements and HDF5: A Preliminary Analysis
2017-04-12
LOGGING STREAM The goal of this report is to investigate logging of EW simulations not at the level of implementation in a database management ...differences of the logging stream and relational models. A hierarchical navigation query style appears very natural for our application. Yet the
-
Shrestha, S; Haramoto, E; Shindo, J
2017-11-01
To assess diarrhoeal risks from enteropathogenic Escherichia coli, Giardia and Cryptosporidium from consuming raw spinach, cabbage, carrots and tomatoes in Kathmandu Valley, Nepal. The annual infection risk was quantified using the probabilistic Quantitative Microbial Risk Assessment approach, which considered 12 vegetable washing combinations. A new model was used to estimate dose of pathogens per exposure comprising parameters such as pathogen concentration in vegetable wash water before selling and eating, vegetable consumption rate, remaining pathogen ratio after washing, remaining water on vegetables after washing and water treatment removal efficiency. When all washing combinations were considered, high infection risks above the acceptable level of -4 log 10 infection per person per year were obtained, whereas the risk was reduced when other sources excluding river water were used. Assuming use of water treated with ceramic filters by all consumers, a 0-2 log 10 reduction in the estimated risks was obtained, which was insufficient to achieve the required risk level. High risk of diarrhoea prevails among raw vegetable consumers in the valley. It is needed to protect vegetable washing water sources and establish advanced water treatment methods to achieve the required level of public health risk. © 2017 The Society for Applied Microbiology.
-
Organic acids for control of Salmonella in different feed materials
2013-01-01
Background Salmonella control in animal feed is important in order to protect animal and public health. Organic acids is one of the control measures used for treatment of Salmonella contaminated feed or feed ingredients. In the present study, the efficacy of formic acid (FA) and different blends of FA, propionic acid (PA) and sodium formate (SF) was investigated. Four Salmonella strains isolated from feed were assayed for their acid tolerance. Also, the effect of lower temperatures (5°C and 15°C) compared to room temperature was investigated in rape seed and soybean meal. Results The efficacy of acid treatments varied significantly between different feed materials. The strongest reduction was seen in pelleted and compound mash feed (2.5 log10 reduction) followed by rapeseed meal (1 log10 reduction) after 5 days exposure. However, in soybean meal the acid effects were limited (less than 0.5 log10 reduction) even after several weeks’ exposure. In all experiments the survival curves showed a concave shape, with a fast initial death phase followed by reduction at a slower rate during the remaining time of the experiment. No difference in Salmonella reduction was observed between FA and a blend of FA and PA, whereas a commercial blend of FA and SF (Amasil) was slightly more efficacious (0.5-1 log10 reduction) than a blend of FA and PA (Luprocid) in compound mash feed. The Salmonella Infantis strain was found to be the most acid tolerant strain followed by, S. Putten, S. Senftenberg and S. Typhimurium. The tolerance of the S. Infantis strain compared with the S. Typhimurium strain was statistically significant (p<0.05). The lethal effect of FA on the S. Typhimurium strain and the S. Infantis strain was lower at 5°C and 15°C compared to room temperatures. Conclusions Acid treatment of Salmonella in feed is a matter of reducing the number of viable bacterial cells rather than eliminating the organism. Recommendations on the use of acids for controlling Salmonella in feed should take into account the relative efficacy of acid treatment in different feed materials, the variation in acid tolerance between different Salmonella strains, and the treatment temperature. PMID:23597100
-
40 CFR 146.66 - Logging, sampling, and testing prior to new well operation.
Code of Federal Regulations, 2010 CFR
2010-07-01
... establish accurate baseline data against which future measurements may be compared. A descriptive report... radioactive tracer survey; (iii) A temperature or noise log; (iv) A casing inspection log, if required by the...
-
40 CFR 146.66 - Logging, sampling, and testing prior to new well operation.
Code of Federal Regulations, 2013 CFR
2013-07-01
... establish accurate baseline data against which future measurements may be compared. A descriptive report... radioactive tracer survey; (iii) A temperature or noise log; (iv) A casing inspection log, if required by the...
-
40 CFR 146.66 - Logging, sampling, and testing prior to new well operation.
Code of Federal Regulations, 2012 CFR
2012-07-01
... establish accurate baseline data against which future measurements may be compared. A descriptive report... radioactive tracer survey; (iii) A temperature or noise log; (iv) A casing inspection log, if required by the...
-
40 CFR 146.66 - Logging, sampling, and testing prior to new well operation.
Code of Federal Regulations, 2014 CFR
2014-07-01
... establish accurate baseline data against which future measurements may be compared. A descriptive report... radioactive tracer survey; (iii) A temperature or noise log; (iv) A casing inspection log, if required by the...
-
40 CFR 146.66 - Logging, sampling, and testing prior to new well operation.
Code of Federal Regulations, 2011 CFR
2011-07-01
... establish accurate baseline data against which future measurements may be compared. A descriptive report... radioactive tracer survey; (iii) A temperature or noise log; (iv) A casing inspection log, if required by the...
-
10 CFR 39.69 - Radioactive contamination control.
Code of Federal Regulations, 2013 CFR
2013-01-01
... Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.69 Radioactive contamination control. (a) If the licensee detects... licensee shall continuously monitor, with an appropriate radiation detection instrument or a logging tool...
-
10 CFR 39.69 - Radioactive contamination control.
Code of Federal Regulations, 2010 CFR
2010-01-01
... Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.69 Radioactive contamination control. (a) If the licensee detects... licensee shall continuously monitor, with an appropriate radiation detection instrument or a logging tool...
-
10 CFR 39.69 - Radioactive contamination control.
Code of Federal Regulations, 2014 CFR
2014-01-01
... Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.69 Radioactive contamination control. (a) If the licensee detects... licensee shall continuously monitor, with an appropriate radiation detection instrument or a logging tool...
-
10 CFR 39.69 - Radioactive contamination control.
Code of Federal Regulations, 2011 CFR
2011-01-01
... Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.69 Radioactive contamination control. (a) If the licensee detects... licensee shall continuously monitor, with an appropriate radiation detection instrument or a logging tool...
-
10 CFR 39.69 - Radioactive contamination control.
Code of Federal Regulations, 2012 CFR
2012-01-01
... Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.69 Radioactive contamination control. (a) If the licensee detects... licensee shall continuously monitor, with an appropriate radiation detection instrument or a logging tool...
-
NASA Astrophysics Data System (ADS)
Scholz-Reiter, B.; Wirth, F.; Dashkovskiy, S.; Makuschewitz, T.; Schönlein, M.; Kosmykov, M.
2011-12-01
We investigate the problem of model reduction with a view to large-scale logistics networks, specifically supply chains. Such networks are modeled by means of graphs, which describe the structure of material flow. An aim of the proposed model reduction procedure is to preserve important features within the network. As a new methodology we introduce the LogRank as a measure for the importance of locations, which is based on the structure of the flows within the network. We argue that these properties reflect relative importance of locations. Based on the LogRank we identify subgraphs of the network that can be neglected or aggregated. The effect of this is discussed for a few motifs. Using this approach we present a meta algorithm for structure-preserving model reduction that can be adapted to different mathematical modeling frameworks. The capabilities of the approach are demonstrated with a test case, where a logistics network is modeled as a Jackson network, i.e., a particular type of queueing network.
-
Feliciano, Lizanel; Lee, Jaesung; Lopes, John A; Pascall, Melvin A
2010-05-01
This study investigated the efficacy of sanitized ice for the reduction of bacteria in the water collected from the ice that melted during storage of whole and filleted Tilapia fish. Also, bacterial reductions on the fish fillets were investigated. The sanitized ice was prepared by freezing solutions of PRO-SAN (an organic acid formulation) and neutral electrolyzed water (NEW). For the whole fish study, the survival of the natural microflora was determined from the water of the melted ice prepared with PRO-SAN and tap water. These water samples were collected during an 8 h storage period. For the fish fillet study, samples were inoculated with Escherichia coli K12, Listeria innocua, and Pseudomonas putida then stored on crushed sanitized ice. The efficacies of these were tested by enumerating each bacterial species on the fish fillet and in the water samples at 12 and 24 h intervals for 72 h, respectively. Results showed that each bacterial population was reduced during the test. However, a bacterial reduction of < 1 log CFU was obtained for the fillet samples. A maximum of approximately 2 log CFU and > 3 log CFU reductions were obtained in the waters sampled after the storage of whole fish and the fillets, respectively. These reductions were significantly (P < 0.05) higher in the water from sanitized ice when compared with the water from the unsanitized melted ice. These results showed that the organic acid formulation and NEW considerably reduced the bacterial numbers in the melted ice and thus reduced the potential for cross-contamination.
-
R. James Barbour; Jeremy Fried; Peter J. Daugherty; Glenn Christensen; Roger. Fight
2008-01-01
The FIA BioSum model was used to simulate three fire-hazard-reduction policies in an area comprising northern California, southwestern Oregon, and the east slopes of the Cascade Mountains in Oregon. The policy scenarios, all subject to a stand-scale fire-hazard-reduction effectiveness constraint, included maximize torching index improvement (Max TI), maximize net...
-
Bryoid layer response to soil disturbance by fuel reduction treatments in a dry conifer forest
Amanda Hardman; Bruce McCune
2010-01-01
We investigated the response of the bryoid layer, bryophyte and lichen communities on the soil surface three years after fuel reduction treatment (logging and burning) in the central Blue Mountains of eastern Oregon. Both treatment and control areas had been decimated by spruce budworm and drought before the fuel reduction treatments. Treatments reduced overstory and...
-
Ganesan, Balasubramanian; Martini, Silvana; Solorio, Jonathan; Walsh, Marie K
2015-01-01
This study investigated the effects of high intensity ultrasound (temperature, amplitude, and time) on the inactivation of indigenous bacteria in pasteurized milk, Bacillus atrophaeus spores inoculated into sterile milk, and Saccharomyces cerevisiae inoculated into sterile orange juice using response surface methodology. The variables investigated were sonication temperature (range from 0 to 84°C), amplitude (range from 0 to 216 μm), and time (range from 0.17 to 5 min) on the response, log microbe reduction. Data were analyzed by statistical analysis system software and three models were developed, each for bacteria, spore, and yeast reduction. Regression analysis identified sonication temperature and amplitude to be significant variables on microbe reduction. Optimization of the inactivation of microbes was found to be at 84.8°C, 216 μm amplitude, and 5.8 min. In addition, the predicted log reductions of microbes at common processing conditions (72°C for 20 sec) using 216 μm amplitude were computed. The experimental responses for bacteria, spore, and yeast reductions fell within the predicted levels, confirming the accuracy of the models.
-
Martini, Silvana; Solorio, Jonathan; Walsh, Marie K.
2015-01-01
This study investigated the effects of high intensity ultrasound (temperature, amplitude, and time) on the inactivation of indigenous bacteria in pasteurized milk, Bacillus atrophaeus spores inoculated into sterile milk, and Saccharomyces cerevisiae inoculated into sterile orange juice using response surface methodology. The variables investigated were sonication temperature (range from 0 to 84°C), amplitude (range from 0 to 216 μm), and time (range from 0.17 to 5 min) on the response, log microbe reduction. Data were analyzed by statistical analysis system software and three models were developed, each for bacteria, spore, and yeast reduction. Regression analysis identified sonication temperature and amplitude to be significant variables on microbe reduction. Optimization of the inactivation of microbes was found to be at 84.8°C, 216 μm amplitude, and 5.8 min. In addition, the predicted log reductions of microbes at common processing conditions (72°C for 20 sec) using 216 μm amplitude were computed. The experimental responses for bacteria, spore, and yeast reductions fell within the predicted levels, confirming the accuracy of the models. PMID:26904659
-
Decontamination of green onions and baby spinach by vaporized ethyl pyruvate.
Durak, M Zeki; Churey, John J; Gates, Matthew; Sacks, Gavin L; Worobo, Randy W
2012-06-01
Foodborne illnesses associated with fresh produce continue to be a major concern as consumer demand for healthier and nonthermally processed food increases. The objective of this study was to evaluate vaporized ethyl pyruvate (EP; CAS 617-35-6) as a safe alternative antimicrobial agent for the decontamination of Escherichia coli O157:H7 on green onions and spinach. Baby spinach leaves and green onions were inoculated with a five-strain cocktail of E. coli O157:H7 (pGFP) by the dipping method. Samples were treated with concentrations of 0, 42, 105, and 420 mg/liter vaporized EP in a 2.6-liter enclosed container. The efficacy of EP vapors for reducing E. coli O157:H7((GFP)) populations on green onions and baby spinach at 4 and 10°C was monitored for 7 and 5 days, respectively. The lowest EP concentration (42 mg/liter) resulted in a 1.7-log reduction of E. coli O157:H7((GFP)) on green onions after 7 days at 4°C and a 1.9-log reduction after 5 days at 10°C (P < 0.05). In baby spinach, the same concentration resulted in 0.9-log and 1.4-log reductions (P < 0.05) of E. coli O157:H7((GFP)) after 7 days at 4°C and 5 days at 10°C, respectively. On green onions, the highest concentration of EP (420 mg/liter) reduced the population of E. coli O157:H7((GFP)) by >4.7 log CFU/g after 7 days at 4°C and 5 days at 10°C. The same concentration was also effective for reducing E. coli O157:H7((GFP)) populations in baby spinach by 4.3 log CFU/g after 7 days at 4°C and by >6.5 log CFU/g after 3 days at 10°C. Although the successful EP treatments minimally affected the sensory attributes of green onions, the treatments resulted in significant changes in the sensory attributes of baby spinach samples stored at 4 and 10°C. These results indicate that EP is an effective antimicrobial that could be used to enhance the safety of fresh produce depending on the sensory characteristics of the product.
-
A CORRELATION BETWEEN RADIATION TOLERANCE AND NUCLEAR SURFACE AREA
DOE Office of Scientific and Technical Information (OSTI.GOV)
Iversen, S.
1962-09-22
Sparrow and Miksche (Science, 134:282) determined the dose (r/day) required to produce severe growth inhibition in 23 species of plants and found a linear relationship between log nuclear volume and log dose. The following equations hold for 6 species: log nuclear volume - 4.42 -0.82 log dose and log nuclear volume = 1.66 + 0.66 log (DNA content). If all the nuclear DNA is distributed in two peripheral zones, the equations also hold: 2(log nuclear surface area) - 1.33(log nuclear volume) - 2.21 + 0.88 log(DNA content) and 5.88-- 1.09 log dose. For the 23 species, the equation was obtained:more » 2(log nuclear surface area) = 5.41 -- 0.97 log dose. All the slopes are close to the expected value of 1.00. (D.L.C.)« less
-
12 CFR 27.4 - Inquiry/Application Log.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Inquiry/Application Log. 27.4 Section 27.4... SYSTEM § 27.4 Inquiry/Application Log. (a) The Comptroller, among other things, may require a bank to maintain a Fair Housing Inquiry/Application Log (“Log”), based upon, but not limited to, one or more of the...
-
12 CFR 27.4 - Inquiry/Application Log.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Inquiry/Application Log. 27.4 Section 27.4... SYSTEM § 27.4 Inquiry/Application Log. (a) The Comptroller, among other things, may require a bank to maintain a Fair Housing Inquiry/Application Log (“Log”), based upon, but not limited to, one or more of the...
-
Development of regional stump-to-mill logging cost estimators
Chris B. LeDoux; John E. Baumgras
1989-01-01
Planning logging operations requires estimating the logging costs for the sale or tract being harvested. Decisions need to be made on equipment selection and its application to terrain. In this paper a methodology is described that has been developed and implemented to solve the problem of accurately estimating logging costs by region. The methodology blends field time...
-
Utilization and cost of log production from animal loging operations
Suraj P. Shrestha; Bobby L. Lanford; Robert B. Rummer; Mark Dubois
2006-01-01
Forest harvesting with animals is a labor-intensive operation. It is expensive to use machines on smaller woodlots, which require frequent moves if mechanically logged. So, small logging systems using animals may be more cost effective. In this study, work sampling was used for five animal logging operations in Alabama to measure productive and non-productive time...
-
Federal Register 2010, 2011, 2012, 2013, 2014
2012-10-26
... mortgage lending institutions are required to use the information generated as a running log throughout the... mortgage lending institutions are required to use the information generated as a running log throughout the...
-
Idaho National Laboratory PCB Annual Document Log and Annual Records Report for calendar year 2014
DOE Office of Scientific and Technical Information (OSTI.GOV)
Layton, Deborah L.
The requirements for the reporting of polychlorinated biphenyl (PCB)-related activities are found in 40 Code of Federal Regulations (CFR) 761 Subpart J, "General Records and Reports." The PCB Annual Document Log is a detailed record of the PCB waste handling activities at the facility. The facility must prepare it each year by July 1 and maintain it at the facility for at least 3 years after the facility ceases using or storing PCBs and PCB items. While submittal of the PCB Annual Document Log to the U.S. Environmental Protection Agency (EPA) is not required by regulation, EPA has verbally requestedmore » in telephone conversations that this report be submitted to them on an annual basis. The Annual Records are not required to be submitted to EPA and are not considered to be part of the Annual Document Log, but are included to provide the complete disposition history or status of all PCB activities during the year. The Annual Document Log section of this report (Section 2.0) meets the requirements of 40 CFR 761.180(a)(2), as applicable, while the Annual Records section (Section 3.0) meets the requirement of 40 CFR 761.180(a)(1).« less
-
Matthew R. Kluber; Deanna H. Olson; Klaus J. Puettmann
2013-01-01
Down wood provides important faunal microhabitat in forests for many invertebrate taxa, small mammals, and amphibians. Habitat suitability of down wood as refugia is an increasing concern in managed forests of the US Pacifi c Northwest, where overstory reduction may result in both reduced down wood recruitment and increased temperatures within logs, which may make them...
-
2002-01-01
chlorinated sample having antibacterial activity ; absence of “Cl” indicates an unchlorinated control. bThe challenge of S. aureus was 1.3 109 CFU (9.1...Table 1 show that when a very high challenge load of S. aureus (9.1 logs) was employed, the chlorinated samples showed rea- sonable antibacterial ...Table IV Regeneration of Antibacterial Activity Sample Chlorination Microbiological Performance (Log Reduction)a PETHCl-1 First: 50% Clorox 9.0 PETH None
-
González, Abelardo; Gehr, Ronald; Vaca, Mabel; López, Raymundo
2012-03-01
Disinfection of an advanced primary effluent using a continuous-flow combined peracetic acid/ultraviolet (PAA/UV) radiation system was evaluated. The purpose was to determine whether the maximum microbial content, established under Mexican standards for treated wastewaters meant for reuse--less than 240 most probable number fecal coliforms (FC)/100 mL--could be feasibly accomplished using either disinfectant individually, or the combined PAA/UV system. This meant achieving reduction of up to 5 logs, considering initial concentrations of 6.4 x 10(+6) to 5.8 x 10(+7) colony forming units/100 mL. During the tests performed under these experiments, total coliforms (TC) were counted because FC, at the most, will be equal to TC. Peracetic acid disinfection achieved less than 1.5 logs TC reduction when the C(t) x t product was less than 2.26 mg x minimum (min)/L; 3.8 logs for C(t) x t 4.40 mg x min/L; and 5.9 logs for C(t) x t 24.2 mg x min/L. In continuous-flow UV irradiation tests, at a low-operating flow (21 L/min; conditions which produced an average UV fluence of 13.0 mJ/cm2), the highest TC reduction was close to 2.5 logs. The only condition that produced a disinfection efficiency of approximately 5 logs, when both disinfection agents were used together, was the combined process dosing 30 mg PAA/L at a pilot plant flow of 21 L/min and contact time of 10 minutes to attain an average C(t) x t product of 24.2 mg x min/L and an average UV fluence of 13 mJ/cm2. There was no conclusive evidence of a synergistic effect when both disinfectants were employed in combination as compared to the individual effects achieved when used separately, but this does not take into account the nonlinearity (tailing-off) of the dose-response curve.
-
Gjoka, Xhorxhi; Gantier, Rene; Schofield, Mark
2017-01-20
The goal of this study was to adapt a batch mAb purification chromatography platform for continuous operation. The experiments and rationale used to convert from batch to continuous operation are described. Experimental data was used to design chromatography methods for continuous operation that would exceed the threshold for critical quality attributes and minimize the consumables required as compared to batch mode of operation. Four unit operations comprising of Protein A capture, viral inactivation, flow-through anion exchange (AEX), and mixed-mode cation exchange chromatography (MMCEX) were integrated across two Cadence BioSMB PD multi-column chromatography systems in order to process a 25L volume of harvested cell culture fluid (HCCF) in less than 12h. Transfer from batch to continuous resulted in an increase in productivity of the Protein A step from 13 to 50g/L/h and of the MMCEX step from 10 to 60g/L/h with no impact on the purification process performance in term of contaminant removal (4.5 log reduction of host cell proteins, 50% reduction in soluble product aggregates) and overall chromatography process yield of recovery (75%). The increase in productivity, combined with continuous operation, reduced the resin volume required for Protein A and MMCEX chromatography by more than 95% compared to batch. The volume of AEX membrane required for flow through operation was reduced by 74%. Moreover, the continuous process required 44% less buffer than an equivalent batch process. This significant reduction in consumables enables cost-effective, disposable, single-use manufacturing. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.
-
Use of acoustics to deter bark beetles from entering tree material.
Aflitto, Nicholas C; Hofstetter, Richard W
2014-12-01
Acoustic technology is a potential tool to protect wood materials and eventually live trees from colonization by bark beetles. Bark beetles such as the southern pine beetle Dendroctonus frontalis, western pine beetle D. brevicomis and pine engraver Ips pini (Coleoptera: Curculionidae) use chemical and acoustic cues to communicate and to locate potential mates and host trees. In this study, the efficacy of sound treatments on D. frontalis, D. brevicomis and I. pini entry into tree materials was tested. Acoustic treatments significantly influenced whether beetles entered pine logs in the laboratory. Playback of artificial sounds reduced D. brevicomis entry into logs, and playback of stress call sounds reduced D. frontalis entry into logs. Sound treatments had no effect on I. pini entry into logs. The reduction in bark beetle entry into logs using particular acoustic treatments indicates that sound could be used as a viable management tool. © 2013 Society of Chemical Industry.
-
Pasteurization of shell eggs using radio frequency heating
DOE Office of Scientific and Technical Information (OSTI.GOV)
Geveke, David J.; Bigley, Andrew B. W.; Brunkhorst, Christopher D.
The USDA-FSIS estimates that pasteurization of all shell eggs in the U.S. would reduce the annual number of illnesses by more than 110,000. However, less than 3% of shell eggs are commercially pasteurized. One of the main reasons for this is that the commercial hot water process requires as much as 60 min to complete. In the present study, a radio frequency (RF) apparatus was constructed, and a two-step process was developed that uses RF energy and hot water, to pasteurize eggs in less than half the time. In order to select an appropriate RF generator, the impedance of shellmore » eggs was measured in the frequency range of 10–70 MHz. The power density within the egg was modeled to prevent potential hotspots. Escherichia coli (ATCC 35218) was inoculated in the yolk to approximately 7.5 log CFU/ml. The combination process first heated the egg in 35.0 °C water for 3.5 min using 60 MHz RF energy. This resulted in the yolk being preferentially heated to 61 °C. Then, the egg was heated for an additional 20 min with 56.7 °C water. This two-step process reduced the population of E. coli by 6.5 log. The total time for the process was 23.5 min. By contrast, processing for 60 min was required to reduce the E. coli by 6.6 log using just hot water. The novel RF pasteurization process presented in this study was considerably faster than the existing commercial process. As a result, this should lead to an increase in the percentage of eggs being pasteurized, as well as a reduction of foodborne illnesses.« less
-
Pasteurization of shell eggs using radio frequency heating
Geveke, David J.; Bigley, Andrew B. W.; Brunkhorst, Christopher D.
2016-08-21
The USDA-FSIS estimates that pasteurization of all shell eggs in the U.S. would reduce the annual number of illnesses by more than 110,000. However, less than 3% of shell eggs are commercially pasteurized. One of the main reasons for this is that the commercial hot water process requires as much as 60 min to complete. In the present study, a radio frequency (RF) apparatus was constructed, and a two-step process was developed that uses RF energy and hot water, to pasteurize eggs in less than half the time. In order to select an appropriate RF generator, the impedance of shellmore » eggs was measured in the frequency range of 10–70 MHz. The power density within the egg was modeled to prevent potential hotspots. Escherichia coli (ATCC 35218) was inoculated in the yolk to approximately 7.5 log CFU/ml. The combination process first heated the egg in 35.0 °C water for 3.5 min using 60 MHz RF energy. This resulted in the yolk being preferentially heated to 61 °C. Then, the egg was heated for an additional 20 min with 56.7 °C water. This two-step process reduced the population of E. coli by 6.5 log. The total time for the process was 23.5 min. By contrast, processing for 60 min was required to reduce the E. coli by 6.6 log using just hot water. The novel RF pasteurization process presented in this study was considerably faster than the existing commercial process. As a result, this should lead to an increase in the percentage of eggs being pasteurized, as well as a reduction of foodborne illnesses.« less
-
Mima, Ewerton Garcia de Oliveira; Ribeiro, Daniela Garcia; Dovigo, Livia Nordi; Vergani, Carlos Eduardo; Bagnato, Vanderlei Salvador
2011-01-01
Abstract Objective: This in vitro study evaluated the effectiveness of photodynamic therapy (PDT) for the inactivation of different species of Candida on maxillary complete dentures. Background data: The treatment of denture stomatitis requires the inactivation of Candida spp. on dentures. PDT has been reported as an effective method for Candida inactivation. Methods: Reference strains of C. albicans, C. glabrata, C. tropicalis, C. dubliniensis and C. krusei were tested. Thirty-four dentures were fabricated in a standardized procedure and subjected to ethylene oxide sterilization. The dentures were individually inoculated with one of the strains and incubated at 37°C for 24 h. Dentures submitted to PDT (P+L+) were individually sprayed with 50 mg/L of Photogem® (PS) and, after 30 min, illuminated by LED light for 26 min (37.5 J/cm2). Additional dentures were treated only with PS (P+L-) or light (P-L+) or neither (P-L-). Samples of serial dilutions were spread on Sabouraud dextrose agar and incubated at 37°C for 48 h. The colonies were counted and the values of log (cfu/mL) were analyzed by Kruskall-Wallis and Dunn tests (p<0.05). Results: For all species of Candida, PDT resulted in significant reduction (p<0.05) of cfu/mL values from dentures when compared with P-L- (reductions from 1.73 to 3.99 log10). Significant differences (p<0.05), but lower reductions, were also observed for P+L- and P-L+when compared with P-L- for some species of Candida. Conclusions: PDT was an effective method for reducing Candida spp. on dentures. PMID:21916614
-
Survival of norovirus surrogate on various food-contact surfaces.
Kim, An-Na; Park, Shin Young; Bae, San-Cheong; Oh, Mi-Hwa; Ha, Sang-Do
2014-09-01
Norovirus (NoV) is an environmental threat to humans, which spreads easily from one infected person to another, causing foodborne and waterborne diseases. Therefore, precautions against NoV infection are important in the preparation of food. The aim of this study was to investigate the survival of murine norovirus (MNV), as a NoV surrogate, on six different food-contact surfaces: ceramic, wood, rubber, glass, stainless steel, and plastic. We inoculated 10(5) PFU of MNV onto the six different surface coupons that were then kept at room temperature for 28 days. On the food-contact surfaces, the greatest reduction in MNV was 2.28 log10 PFU/coupon, observed on stainless steel, while the lowest MNV reduction was 1.29 log10 PFU/coupon, observed on wood. The rank order of MNV reduction, from highest to lowest, was stainless steel, plastic, rubber, glass, ceramic, and wood. The values of d R (time required to reduce the virus by 90%) on survival plots of MNV determined by a modified Weibull model were 277.60 h (R(2) = 0.99) on ceramic, 492.59 h (R(2) = 0.98) on wood, 173.56 h on rubber (R(2) = 0.98), 97.18 h (R(2) = 0.94) on glass, 91.76 h (R(2) = 0.97) on stainless steel, and 137.74 h (R(2) = 0.97) on plastic. The infectivity of MNV on all food-contact surfaces remained after 28 days. These results show that MNV persists in an infective state on various food-contact surfaces for long periods. This study may provide valuable information for the control of NoV on various food-contact surfaces, in order to prevent foodborne disease.
-
Required Operational Capability, USMC-ROC-LOG-216.3.5 for the Ration, Cold Weather.
1987-05-06
in operations or training in an arctic environment . b. Organizational Concept. The ration , cold weather will be issued in accordance with established...all services. 2 ROC-ARCTIC 7. TECHNICAL FEASIBILITY AND ENERGY/ ENVIRONMENTAL IMPACTS a. Technical Feasibility. The risk of developing the ration ...r -A1833 963 REQUIRED OPERATIONAL CAPABILITY USMC-ROC-LOG-21635 FOR 1t/1 THE RATION COLD WEATHER(U) MARINE CORPS WASHINGTON DC 86 MAY 87 USMC-ROC-LOG
-
Mathurand, Prateek; Schaffner, Donald W
2013-06-01
Ceviche is a raw fish dish common in Peru and other Latin American counties. The most characteristic feature of ceviche is the use of lime juice for marinating or "cooking" the raw fish. Confirmed cases of cholera in Peru, New Jersey, and Florida have been associated with ceviche. Although the effect of organic acids on pathogenic bacteria has been well characterized, few data exist on the effect of these acids in seafood systems. The objective of the study was to evaluate the effects of lime juice marination on pathogens likely to be present in ceviche. Tilapia (Oreochromis niloticus) fillet pieces were inoculated with Vibrio parahaemolyticus and Salmonella enterica (>7 log CFU/g) and incubated at 25 and 4°C for 30 or 120 min in the presence of fresh lime juice at concentrations typical for the preparation of ceviche. Similar levels of cells were also inoculated into fresh lime juice without tilapia. Surviving cells were enumerated on selective (xylose lysine Tergitol 4 and thiosulfate-bile-citrate-sucrose) and nonselective (tryptic soy agar) media. V. parahaemolyticus levels were reduced to below detection limits (∼5-log reduction) under all conditions studied. Salmonella strains on tilapia were much more resistant to inactivation and were only slightly reduced (∼1- to 2-log reduction). Salmonella and V. parahaemolyticus inoculated directly into lime juice without tilapia were all reduced to below detection limits (∼5-log reduction). A typical ceviche recipe reduces V. parahaemolyticus risk significantly but is less effective for control of S. enterica.
-
Cronobacter sakazakii reduction by blueberry proanthocyanidins.
Joshi, Snehal S; Howell, Amy B; D'Souza, Doris H
2014-05-01
Blueberry juice and blueberry polyphenols reportedly have antimicrobial properties against foodborne pathogens, without much currently known on their effects against Cronobacter sakazakii. This study evaluated the antimicrobial effects of blueberry proanthocyanidins (PAC) and commercial blueberry juice (BJ) against two strains of C. sakazakii, ATCC 29004 and 29544. BJ (pH 2.8), blueberry PAC (5 mg/ml) and controls (phosphate buffered saline (PBS), pH 7.2, and malic acid pH 3.0) were mixed with equal volumes of washed overnight cultures of C. sakazakii and incubated for 30 min, 1 h, 3 h and 6 h at 37°C. Reductions of ∼1 and 1.50 log CFU/ml were obtained for strains 29004 and 29544, respectively after 30 min with BJ or blueberry PAC. Both C. sakazakii strains 29004 and 29544 were reduced to undetectable levels from 8.25 ± 0.12 log CFU/ml and 8.48 ± 0.03 log CFU/ml, respectively with BJ (pH 2.8) or blueberry PAC after 1 h, while malic acid (pH 3.0) showed ∼1.3 log CFU/ml reduction for both strains. Scanning electron microscopy studies showed differences in cell membrane morphology with clumping and formation of blebs of the treated strains compared to untreated controls. These results warrant further in vivo studies with blueberry bioactives to determine potential for preventing and treating C. sakazakii infections. Copyright © 2013. Published by Elsevier Ltd.
-
Hudson, J A; Billington, C; Wilson, T; On, S L W
2015-03-01
A previously described phage infecting Escherichia coli O157:H7 was added to raw and cooked beef pieces at concentrations ranging from 10(1)-10(8) plaque forming units/cm(2) to either low (<100 CFU/cm(2)) or high (10(4) CFU/cm(2)) concentrations of host bacterial cells. Incubation for up to 24 h was performed at 5 ℃ and 24 ℃ to simulate refrigerated and room temperature storage/temperature abuse. Surviving bacteria were enumerated during the incubation period, with phages being counted at the first and last sampling times. Significant reductions of E. coli O157:H7 of the order of >4 log10 CFU/cm(2) at both temperatures could be achieved compared to phage-free controls. There was a trend for greater inactivation to occur with increasing phage concentration. While re-growth of surviving cells occurred in nearly all samples incubated for 24 h at 24 ℃, these conditions are not typical of those experienced by perishable foods. It was concluded that phages can be used to reduce the concentration of a bacterial pathogen on meat, but the concentration of phages needs to be high (>4-5 log10 plaque forming units/cm(2)) for reductions to occur. A concentration of the order 8 log10 plaque forming units/cm(2) was needed to achieve a 4 log10 CFU/cm(2) reduction. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
-
Kim, Nam Hee; Jang, Seong Ho; Kim, Soon Han; Lee, Hee Jung; Kim, Younghoon; Ryu, Jee Hoon; Rhee, Min Suk
2015-12-02
The aim of this study was to develop a new salting method using natural phytic acid (PA) to ensure the microbiological safety and quality of salted napa cabbage used for kimchi production. The production of salted napa cabbage involves several stages: trimming, hyper-salting (20% NaCl) for up to 1h, salting (10% NaCl for 10-18 h), three sequential washes in water (30s for each), and draining (2 h). Two separate experiments were performed: one to determine the appropriate treatment conditions and a second to validate applicability under commercial conditions. In Experiment I, the effects of hyper-salting with PA on Escherichia coli O157:H7 numbers were tested in the laboratory. The following variables were monitored: 1) PA concentration (1, 2, 3%, w/w); 2) the ratio of the sample weight to the total volume of the solution (1:1.5, 1:3, or 1:6); 3) the hyper-salting time (30 or 60 min); and 4) the salting time (2, 5, or 8 h). A procedure that achieved a >5-log reduction in the E. coli O157:H7 population was then tested in an actual kimchi processing plant (Experiment II). The results from Experiment I showed that bactericidal efficacy increased as all the measured variables increased (p<0.05). Hyper-salting with 2% PA at a sample-to-water ratio (w/v) of 1:3 and 1:6 for 60 min resulted in a >5-log CFU/g reduction in the E. coli O157:H7 population. Further salting for 5h completely eliminated (<1-log CFU/g) all bacteria. Thus, hyper-salting with PA 2% at a sample-to-water ratio of 1:3 for 60 min, followed by salting for 5h, was tested under large-scale production conditions. The results revealed that the initial aerobic plate counts (APC), total coliform counts (TC), and fecal coliform counts (FC) were 6.6, 3.4, and 2.8-log CFU/g, respectively. The selected protocol reduced these values by 3.7-, >2.4-, and >1.8-log CFU/g, respectively. The 5h salting step maintained the TC and FC at <1-log CFU/g; however, the APC recovered somewhat. The pH and salinity of the treated salted napa cabbages were within the ranges required for kimchi production (pH 5.1-5.3 and 1.5-2.0%, respectively). These results suggest that this novel method of salting food ensures microbiological safety and reduces the production time. Copyright © 2015 Elsevier B.V. All rights reserved.
-
Predicting internal yellow-poplar log defect features using surface indicators
R. Edward Thomas
2008-01-01
Determining the defects that are located within the log is crucial to understanding the tree/log resource for efficient processing. However, existing means of doing this non-destructively requires the use of expensive X-ray/CT, MRI, or microwave technology. These methods do not lend themselves to fast, efficient, and cost-effective analysis of logs and tree stems in...
-
Effectiveness of lemon juice in the elimination of Salmonella Typhimurium in stuffed mussels.
Kişla, Duygu
2007-12-01
Street foods are becoming more and more prominent in countries all over the world. There are many reports of disease due to consumption of street foods contaminated by pathogens. With the modern trend toward more natural preservatives, the use of organic acids can achieve a good microbiological safety in food. In the present study, stuffed mussels were inoculated with Salmonella Typhimurium suspension to provide initial populations of approximately 6 and 3 log CFU/g. After inoculation, samples were treated with fresh lemon juice and lemon dressing for 0, 5, and 15 min, and pathogens were enumerated by using direct plating on brilliant green agar. Treatment of stuffed mussels inoculated at high inoculum level, with lemon juice and lemon dressing for different exposure times caused reduction ranging between 0.25 and 0.56 log CFU/g and 0.5 and 0.69 log CFU/g, respectively, whereas in stuffed-mussel samples inoculated at low level, lemon juice and lemon dressing caused 0.08 to 0.25 log CFU/g and 0.22 to 0.78 log CFU/g reductions, respectively. Results of the study showed that both lemon juice and lemon dressing used as flavoring and acidifying agents for stuffed mussels caused slight decrease in Salmonella Typhimurium as an immediate inhibitor, but this effect increased by time. However, treatment of stuffed mussels with the inhibitors until 15 min is not enough to prevent Salmonella Typhimurium outbreaks related to stuffed mussels.
-
Pangloli, Philipus; Hung, Yen-Con
2011-08-01
The objective of this study was to evaluate the efficacy of slightly acidic electrolyzed (SAEO) water in killing or removing Escherichia coli O157:H7 on iceberg lettuce and tomatoes by washing and chilling treatment simulating protocols used in food service kitchens. Whole lettuce leaves and tomatoes were spot-inoculated with 100 μL of a mixture of 5 strains of E. coli O157:H7. Washing lettuce with SAEO water for 15 s reduced the pathogen by 1.4 to 1.6 log CFU/leaf, but the treatments did not completely inactivate the pathogen in the wash solution. Increasing the washing time to 30 s increased the reductions to 1.7 to 2.3 log CFU/leaf. Sequential washing in SAEO water for 15 s and then chilling in SAEO water for 15 min also increased the reductions to 2.0 to 2.4 log CFU/leaf, and no cell survived in chilling solution after treatment. Washing tomatoes with SAEO water for 8 s reduced E. coli O157:H7 by 5.4 to 6.3 log CFU/tomato. The reductions were increased to 6.6 to 7.6 log CFU/tomato by increasing the washing time to 15 s. Results suggested that application of SAEO water to wash and chill lettuce and tomatoes in food service kitchens could minimize cross-contamination and reduce the risk of E. coli O157:H7 present on the produce. SAEO water is equally or slightly better than acidic electrolyzed (AEO) water for inactivation of bacteria on lettuce and tomato surfaces. In addition, SAEO water may have the advantages over AEO water on its stability, no chlorine smell, and low corrosiveness. Therefore, SAEO water may have potential for produce wash to enhance food safety. © 2011 Institute of Food Technologists®
-
Berrang, Mark E; Hofacre, Charles L; Frank, Joseph F
2014-12-01
Listeria monocytogenes can colonize a poultry processing plant as a resident in floor drains. Limiting growth and attachment to drain surfaces may help lessen the potential for cross-contamination of product. The objective of this study was to compare a hydrogen peroxide-peroxyacetic acid-based chemical to chitosan-arginine or heat to prevent attachment of or destroy existing L. monocytogenes on the inner surface of model floor drains. L. monocytogenes was introduced to result in about 10(9) planktonic and attached cells within untreated polyvinyl chloride model drain pipes. Treatments (0.13 % peroxide-based sanitizer, 0.1 % chitosan-arginine, or 15 s of hot water at 95 to 100°C) were applied immediately after inoculation or after 24 h of incubation. Following treatment, all pipes were incubated for an additional 24 h; planktonic and attached cells were enumerated by plate count. All treatments significantly (P < 0.05) lowered numbers of planktonic and attached cells recovered. Chitosan-arginine resulted in approximately a 6-log reduction in planktonic cells when applied prior to incubation and a 3-log reduction after the inoculum had a chance to grow. Both heat and peroxide significantly outperformed chitosan-arginine (8- to 9-log reduction) and were equally effective before and after incubation. Heat was the only treatment that eliminated planktonic L. monocytogenes. All treatments were less effective against attached cells. Chitosan-arginine provided about a 4.5-log decrease in attached cells when applied before incubation and no significant decrease when applied after growth. Like with planktonic cells, peroxide-peroxyacetic acid and heat were equally effective before or after incubation, causing decreases ranging from 7 to 8.5 log for attached L. monocytogenes. Applied at the most efficacious time, any of these techniques may lessen the potential for L. monocytogenes to remain as a long-term resident in processing plant floor drains.
-
Survival of selected foodborne pathogens on dry cured pork loins.
Morales-Partera, Ángela M; Cardoso-Toset, Fernando; Jurado-Martos, Francisco; Astorga, Rafael J; Huerta, Belén; Luque, Inmaculada; Tarradas, Carmen; Gómez-Laguna, Jaime
2017-10-03
The safety of ready-to-eat products such as cured pork loins must be guaranteed by the food industry. In the present study, the efficacy of the dry curing process of pork loins obtained from free-range pigs in the reduction of three of the most important foodborne pathogens is analysed. A total of 28 pork loin segments, with an average weight of 0.57±0.12kg, were divided into four groups with three being inoculated by immersion with 7logCFU/ml of either Salmonella Typhimurium, Campylobacter coli or Listeria innocua and the last one inoculated by immersion with sterile medium (control group). The loin segments were treated with a seasoning mixture of curing agents and spices, packed in a synthetic sausage casing and cured for 64days. Microbiological analysis, pH and water activity (a w ) were assessed at four stages. The values of pH and a w decreased with curing time as expected. S. Typhimurium and C. coli dropped significantly (3.28 and 2.14 log units, respectively), but limited reduction of L. innocua (0.84 log unit) was observed along the curing process. In our study, three factors were considered critical: the initial concentration of the bacteria, the progressive reduction of pH and the reduction of a w values. Our results encourage performing periodic analysis at different stages of the manufacturing of dry cured pork loins to ensure the absence of the three evaluated foodborne pathogens. Copyright © 2017 Elsevier B.V. All rights reserved.
-
Review of current technologies for reduction of Salmonella populations on almonds
USDA-ARS?s Scientific Manuscript database
After the 2001 and 2004 Salmonellosis outbreaks that were associated with raw almonds, ensuring the microbial safety of almonds by treating them to achieve a minimum 4-log reduction of Salmonella population became mandatory in California, the world’s largest almond producer. In this paper, we summa...
-
Forest age-induced changes in evapotranspiration and water yield in a eucalypt forest
NASA Astrophysics Data System (ADS)
Cornish, P. M.; Vertessy, R. A.
2001-02-01
Water yields in a regrowth eucalypt forest were found to increase initially and then to decline below pre-treatment levels during the 16-year period which followed the logging of a moist old-growth eucalypt forest in Eastern Australia. Both regrowth and old-growth stands were dominated by Sydney Blue Gum ( Eucalyptus saligna Smith) and Silvertop Stringybark ( Eucalyptus laevopinea R. Baker). Using a paired-catchment approach we observed significant reductions in five of six gauged catchments, and were able to associate their magnitude with forest growth rate, canopy cover and soil depth. Regular yield declines were interrupted for a period in some catchments, possibly due to foliar insect attack. Yield reductions of up to a maximum 600 mm per year in logged and regenerated areas were in accord with water yield reductions observed in Mountain Ash ( Eucalyptus regnans F.J. Muell.) regeneration in Victoria. This study therefore represents the first confirmation of these Maroondah Mountain Ash results in another forest type that has also undergone eucalypt-to-eucalypt succession. Baseflow analysis indicated that baseflow and stormflow both increased after logging, with stormflow increases dominant in catchments with shallower soils. The lower runoff observed when the regenerating forest was aged 13-16 years was principally a consequence of lower baseflow.
-
Changes in biomarkers of bone turnover in an aripiprazole add-on or switching study.
Lodhi, Rohit J; Masand, Salaj; Malik, Amna; Shivakumar, Kuppuswami; McAllister, Victoria D M; O'Keane, Veronica; Young, Leah C; Heald, Adrian H; Sherwood, Roy A; Aitchison, Katherine J
2016-02-01
The association between mental illness and osteoporosis and fractures is particularly pronounced in psychotic disorders. Antipsychotic use has previously been described to affect bone density. A 52-week follow-up of patients switched to aripiprazole or with aripiprazole added on, conducting a specific analysis of markers of bone turnover: urinary NTX (a biomarker of bone resorption) and serum BSAP (a biomarker of bone formation). Baseline and serial measurements of bone markers NTX, BSAP and of hormones prolactin, oestrogen and testosterone were done at weeks 0 and 1, 2, 6, 12, 26 and 52, respectively. NTX concentration reduced over time but this did not reach significance in the whole group (log-NTX: β=-0.0012, p=0.142). For BSAP the addition of or replacement with aripiprazole produced a significant reduction (log-BSAP: β=-0.00039, p=0.002). Analysis with prolactin similarly showed a significant reduction (log-prolactin: β=-0.0024, p<0.001); other hormones did not change significantly. Sensitivity analysis to compare the switchers to aripiprazole versus the "add-on" showed that the former group had a significant reduction in NTX. We found that switching to aripiprazole was associated with changes in molecular biomarkers of bone resorption, indicating a more favourable profile for bone health. Copyright © 2015 Elsevier B.V. All rights reserved.
-
Maletta, Anne B; Were, Lilian M
2012-02-01
The antimicrobial effect of roasted coffee filtrate (CF) and dicarbonyls on Salmonella Typhimurium and Salmonella Enteritidis in raw ground chicken breast meat (GCB) was investigated. Coffee was brewed and filtered before addition to GCB. Coffee filtrate with and without added caffeine, methylglyoxal, and/or glyoxal was added to GCB and then inoculated with Salmonella Typhimurium and Salmonella Enteritidis. Ground chicken samples were stomached with peptone water at days 1, 3, 5, and 7, plated on XLD agar with a TSA overlay, and Salmonella survivors were enumerated. CF alone gave less than a 1 Log reduction in all runs compared to control GCB with no treatment. Methylglyoxal (2.28 mg/g GCB) had the greatest antimicrobial effect against Salmonella Typhimurium and Salmonella Enteritidis in GCB with average Log reductions of 2.27 to 3.23, respectively, over the 7 d duration of the experiment compared to control GCB with no treatment. A 1 Log reduction was observed in GCB with CF, 0.93 mg glyoxal, and 1 mg caffeine/g chicken compared to the control and GCB with only CF. Heat-produced coffee compounds could potentially reduce Salmonella in retail ground chicken and chicken products. © 2011 Institute of Food Technologists®
-
Arqués, J L; Garde, S; Gaya, P; Medina, M; Nuñez, M
2006-03-01
La Serena cheese, a Spanish variety made from Merino ewes' raw milk, has a high pH value, low salt content, and high moisture, conditions that are all favorable for growth and survival of contaminating microorganisms, including pathogens. To improve its microbiological quality and safety, high-pressure treatments at 300 or 400 MPa for 10 min at 10 degrees C were applied to 2 batches of La Serena cheese on d 2 or 50 of ripening. Cheese treated on d 2 at 300 MPa showed viable aerobic counts that were 0.99 log units lower than those for control cheese on d 3 and showed counts of enterococci, coagulase-positive staphylococci, gram-negative bacteria, and coliforms that were 2.05, 0.49, 3.14, and 4.13 log units lower, respectively, than control cheese. For cheese treated on d 2 at 400 MPa, the respective reductions in counts were 2.02, 2.68, 1.45, 3.96, and 5.50 log units. On d 60, viable aerobic counts in cheese treated on d 50 at 300 MPa were 0.50 log units lower than those in control cheese, and counts of enterococci, gram-negative bacteria, and coliforms were 1.37, 2.30, and 4.85 log units lower, respectively. For cheese treated on d 50 at 400 MPa, the respective reductions in counts were 1.29, 1.98, 4.47, and > 5 log units. High-pressure treatments at 300 or 400 MPa on d 2 or 50 reduced significantly the counts of undesirable microorganisms, improving the microbiological quality and safety of La Serena cheese immediately after treatment and at the end of the ripening period.
-
Phage applications for improving food safety and infection control in Egypt.
El-Shibiny, A; El-Sahhar, S; Adel, M
2017-08-01
The study investigated the use of bacteriophages to control bacterial contamination of chicken skin, eggs, tomatoes and meat. Experiments were performed to test the host ranges and killing potential of two isolated phages, ZCSE1 and ZCEC1, with hosts Salmonella and Escherichia coli respectively. The efficacy of both phages was determined by comparing the viable counts of recovered bacteria from treatment and phage-free control samples. In vitro experiments showed that phage ZCSE1 was able to reduce the numbers of Salmonella enterica ATCC 25566 to below 4·0 log 10 CFU per ml (3·4 log 10 CFU per ml reduction) in 240 min postinfection and phage ZCEC1 reduced the number of E. coli ATCC 8739 to undetectable levels (6·45 log 10 CFU per ml reduction) during the first hour of infection at 37°C. When applied to chicken skin and the surface of eggs, phage ZCSE1 treatment reduced the number of S. enterica ATCC 25566 by 2 log 10 and to undetectable levels (<2·0 log 10 CFU per ml), for skin and eggs respectively (P < 0·005). The administration of ZCEC1 phage to meat and tomatoes reduced the number of E. coli to below 2·0 log 10 CFU per ml 1 day after treatment. The administration of these phages to meat and tomatoes reduced the numbers of E. coli and Salmonella significantly in tested foods. The results suggest that phages could be effective treatments for pathogenic bacteria in food relevant contexts in Egypt. © 2017 The Society for Applied Microbiology.
-
Seasoning degrade in kiln drying ponderosa pine in south central Oregon.
A.C. Knauss
1957-01-01
This report presents the results of a study to determine the loss in volume and value of lumber when kiln drying and surfacing the production from ponderosa pine logs. The study measured (1) the reduction in volume due to trimming and culling dry lumber after surfacing, (2) the reduction in grade due to seasoning defects, (3) the reduction in grade due to failure of...
-
Idaho National Laboratory PCB Annual Document Log and Annual Records Report for Calendar Year 2013
DOE Office of Scientific and Technical Information (OSTI.GOV)
no name on report
The requirements for the reporting of polychlorinated biphenyl (PCB)-related activities are found in 40 Code of Federal Regulations (CFR) 761 Subpart J, "General Records and Reports." The PCB Annual Document Log is a detailed record of the PCB waste handling activities at the facility. The facility must prepare it each year by July 1 and maintain it at the facility for at least 3 years after the facility ceases using or storing PCBs and PCB items. While submittal of the PCB Annual Document Log to the U.S. Environmental Protection Agency (EPA) is not required by regulation, EPA has verbally requestedmore » in telephone conversations that this report be submitted to them on an annual basis. The Annual Document Log section of this report meets the requirements of 40 CFR 761.180(a)(2), as applicable, while the Annual Records section meets the requirement of 40 CFR 761.180(a)(1).« less
-
Pathogen inactivation in liquid dairy manure during anaerobic and aerobic digestions
NASA Astrophysics Data System (ADS)
Biswas, S.; Pandey, P.; Castillo, A. R.; Vaddella, V. K.
2014-12-01
Controlling manure-borne pathogens such as E. coli O157:H7, Salmonella spp. and Listeria monocytogenes are crucial for protecting surface and ground water as well as mitigating risks to human health. In California dairy farms, flushing of dairy manure (mainly animal feces and urine) from freestall barns and subsequent liquid-solid manure separation is a common practice for handling animal waste. The liquid manure fraction is generally pumped into the settling ponds and it goes into aerobic and/or anaerobic lagoons for extended period of time. Considering the importance of controlling pathogens in animal waste, the objective of the study was to understand the effects of anaerobic and aerobic digestions on the survival of three human pathogens in animal waste. The pathogen inactivation was assessed at four temperatures (30, 35, 42, and 50 °C), and the relationships between temperature and pathogen decay were estimated. Results showed a steady decrease of E. coli levels in aerobic and anaerobic digestion processes over the time; however, the decay rates varied with pathogens. The effect of temperature on Salmonella spp. and Listeria monocytogenes survival was different than the E. coli survival. In thermophilic temperatures (42 and 50 °C), decay rate was considerable greater compared to the mesophilic temperatures (30 and 35°C). The E. coli log reductions at 50 °C were 2.1 in both aerobic and anaerobic digestions after 13 days of incubation. The Salmonella spp. log reductions at 50 °C were 5.5 in aerobic digestion, and 5.9 in anaerobic digestion. The Listeria monocytogenes log reductions at 50 °C were 5.0 in aerobic digestion, and 5.6 in anaerobic digestion. The log reduction of E. coli, Salmonella spp., and Listeria monocytogens at 30 °C in aerobic environment were 0.1, 4.7, and 5.6, respectively. In anaerobic environment, the corresponding reductions were 0.4, 4.3, and 5.6, respectively. We anticipate that the outcomes of the study will help improving the existing animal waste management processes to control manure-borne pathogens.
-
NASA Astrophysics Data System (ADS)
Boekema, B. K. H. L.; Vlig, M.; Guijt, D.; Hijnen, K.; Hofmann, S.; Smits, P.; Sobota, A.; van Veldhuizen, E. M.; Bruggeman, P.; Middelkoop, E.
2016-02-01
Cold plasma has been shown to provide a promising alternative antimicrobial treatment for wound healing. We developed and tested a flexible surface dielectric barrier discharge (DBD) and compared it to an argon gas based plasma jet operated remotely with a distance between plasma plume and sample of 8 mm. Tests were conducted using different models: on cultured cells, on ex vivo human skin and on bacteria (Pseudomonas aeruginosa) (on agar, in suspension, in collagen/elastin matrix or on ex vivo human skin), allowing us to directly compare bactericidal with safety aspects under identical conditions. Both plasma devices were highly efficient when used on bacteria in non-buffered solutions, but DBD was faster in reaching the maximum bacterial reduction. Treatment of bacteria on intact skin with DBD resulted in up to 6 log reductions in 3 min. The jet was far less efficient on intact skin. Even after 8 min treatment no more than 2 log reductions were obtained with the jet. Treatment of bacteria in burn wound models with DBD for 6 min resulted in a 4.5 log reduction. Even when using DBD for 6 min on infected burn wound models with colonizing or biofilm phase bacteria, the log reductions were 3.8 or 3.2 respectively. DBD plasma treatment for 6 min did not affect fibroblast viability, whereas a treatment for 8 min was detrimental. Similarly, treatment with DBD or plasma jet for 6 min did also not affect the metabolic activity of skin biopsies. After treatment for 8 min with DBD or plasma jet, 78% or 60% of activity in skin biopsies remained, respectively. Multiple treatments of in vitro burn wound models with surface DBD for 6 min or with plasma jet for 8 min did not affect re-epithelialization. With the flexible surface DBD plasma strip we were able to quickly inactivate large numbers of bacteria on and in skin. Under the same conditions, viability of skin cells or re-epithelialization was not affected. The DBD source has potential for treating larger wound areas.
-
March, Jordon K; Pratt, Michael D; Lowe, Chinn-Woan; Cohen, Marissa N; Satterfield, Benjamin A; Schaalje, Bruce; O'Neill, Kim L; Robison, Richard A
2015-10-01
This study investigated (1) the susceptibility of Bacillus anthracis (Ames strain), Bacillus subtilis (ATCC 19659), and Clostridium sporogenes (ATCC 3584) spores to commercially available peracetic acid (PAA)- and glutaraldehyde (GA)-based disinfectants, (2) the effects that heat-shocking spores after treatment with these disinfectants has on spore recovery, and (3) the timing of heat-shocking after disinfectant treatment that promotes the optimal recovery of spores deposited on carriers. Suspension tests were used to obtain inactivation kinetics for the disinfectants against three spore types. The effects of heat-shocking spores after disinfectant treatment were also determined. Generalized linear mixed models were used to estimate 6-log reduction times for each spore type, disinfectant, and heat treatment combination. Reduction times were compared statistically using the delta method. Carrier tests were performed according to AOAC Official Method 966.04 and a modified version that employed immediate heat-shocking after disinfectant treatment. Carrier test results were analyzed using Fisher's exact test. PAA-based disinfectants had significantly shorter 6-log reduction times than the GA-based disinfectant. Heat-shocking B. anthracis spores after PAA treatment resulted in significantly shorter 6-log reduction times. Conversely, heat-shocking B. subtilis spores after PAA treatment resulted in significantly longer 6-log reduction times. Significant interactions were also observed between spore type, disinfectant, and heat treatment combinations. Immediately heat-shocking spore carriers after disinfectant treatment produced greater spore recovery. Sporicidal activities of disinfectants were not consistent across spore species. The effects of heat-shocking spores after disinfectant treatment were dependent on both disinfectant and spore species. Caution must be used when extrapolating sporicidal data of disinfectants from one spore species to another. Heat-shocking provides a more accurate picture of spore survival for only some disinfectant/spore combinations. Collaborative studies should be conducted to further examine a revision of AOAC Official Method 966.04 relative to heat-shocking. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.
-
Moore, A; Nannapaneni, R; Kiess, A; Sharma, C S
2017-07-01
The main objective of this study was to examine the efficacy of USDA approved antimicrobials in reducing Salmonella Heidelberg (S. H.) and Campylobacter jejuni (C. j.) in ground chicken frames and to determine the treatment effects on total aerobic counts and meat color. Six antimicrobials (0.1% peracetic acid [PAA], 0.6% cetylpyridinium chloride [CPC], 0.005% sodium hypochlorite, 1.5% acidified lactic acid [ALA], 0.3% propionic acid, and 0.1% lauric arginate [LAE]) applied as dip treatments were evaluated in their efficacy in reducing S. Heidelberg and C. jejuni. Fresh chicken frames were spot inoculated with nalidixic acid resistant S. H. and C. j. (ATCC 33291) to achieve a recovery level of ca. 3 log CFU/g in the ground product. Frames were dipped for 10 s in each antimicrobial solution and each treatment was replicated on 3 frames. Three separate replications were conducted for this experiment. Frames were blended, and ground samples similar to mechanically separated chicken (MSC) were obtained and stored at 4°C for 24 hours. Samples were analyzed after grinding on d zero (2 h) and d one (24 h) to determine reduction in S. H. and C. j. counts in MSC. PAA and LAE treatments had the highest reductions on Salmonella counts (P ≤ 0.05), both treatments resulting in 0.9 log CFU/g reduction as compared to control on d zero. PAA and CPC reduced Salmonella counts by 1.4 and 0.9 log CFU/g, respectively, on d one; PAA, propionic acid, ALA, and LAE resulted in one log CFU/g reductions of C. j. as compared to control on d one. There was no significant difference among the treatments in their ability to reduce C. j. on d one. The treatments had no effect on total aerobic counts. The findings from the study indicate that PAA, CPC, and LAE can reduce S. H. in ground chicken frames, whereas all the antimicrobials tested in the study, except chlorine, have the ability to reduce C. j. in ground chicken frames, a product similar to commercial MSC. © 2017 Poultry Science Association Inc.
-
Minimizing inner product data dependencies in conjugate gradient iteration
NASA Technical Reports Server (NTRS)
Vanrosendale, J.
1983-01-01
The amount of concurrency available in conjugate gradient iteration is limited by the summations required in the inner product computations. The inner product of two vectors of length N requires time c log(N), if N or more processors are available. This paper describes an algebraic restructuring of the conjugate gradient algorithm which minimizes data dependencies due to inner product calculations. After an initial start up, the new algorithm can perform a conjugate gradient iteration in time c*log(log(N)).
-
Cold plasma rapid decontamination of food contact surfaces contaminated with Salmonella biofilms.
Niemira, Brendan A; Boyd, Glenn; Sites, Joseph
2014-05-01
Cross-contamination of foods from persistent pathogen reservoirs is a known risk factor in processing environments. Industry requires a rapid, waterless, zero-contact, chemical-free method for removing pathogens from food contact surfaces. Cold plasma was tested for its ability to inactivate Salmonella biofilms. A 3-strain Salmonella culture was grown to form adherent biofilms for 24, 48, or 72 h on a test surface (glass slides). These were placed on a conveyor belt and passed at various line speeds to provide exposure times of 5, 10, or 15 s. The test plate was either 5 or 7.5 cm under a plasma jet emitter operating at 1 atm using filtered air as the feed gas. The frequency of high-voltage electricity was varied from 23 to 48 kHz. At the closer spacing (5 cm), cold plasma reduced Salmonella biofilms by up to 1.57 log CFU/mL (5 s), 1.82 log CFU/mL (10 s), and 2.13 log CFU/mL (15 s). Increasing the distance to 7.5 cm generally reduced the efficacy of the 15 s treatment, but had variable effects on the 5 and 10 s treatments. Variation of the high-voltage electricity had a greater effect on 10 and 15 s treatments, particularly at the 7.5 cm spacing. For each combination of time, distance, and frequency, Salmonella biofilms of 24, 48, and 72 h growth responded consistently with each other. The results show that short treatments with cold plasma yielded up to a 2.13 log reduction of a durable form of Salmonella contamination on a model food contact surface. This technology shows promise as a possible tool for rapid disinfection of materials associated with food processing. Pathogens such as Salmonella can form chemical-resistant biofilms, making them difficult to remove from food contact surfaces. A 15 s treatment with cold plasma reduced mature Salmonella biofilms by up to 2.13 log CFU/mL (99.3%). This contact-free, waterless method uses no chemical sanitizers. Cold plasma may therefore have a practical application for conveyor belts, equipment, and other food contact surfaces where a rapid, dry antimicrobial process is required. © 2014 Institute of Food Technologists®
-
Ultraviolet-C Irradiation: A Novel Pasteurization Method for Donor Human Milk
Christen, Lukas; Lai, Ching Tat; Hartmann, Ben; Hartmann, Peter E.; Geddes, Donna T.
2013-01-01
Background Holder pasteurization (milk held at 62.5°C for 30 minutes) is the standard treatment method for donor human milk. Although this method of pasteurization is able to inactivate most bacteria, it also inactivates important bioactive components. Therefore, the objective of this study was to investigate ultraviolet irradiation as an alternative treatment method for donor human milk. Methods Human milk samples were inoculated with five species of bacteria and then UV-C irradiated. Untreated and treated samples were analysed for bacterial content, bile salt stimulated lipase (BSSL) activity, alkaline phosphatase (ALP) activity, and fatty acid profile. Results All five species of bacteria reacted similarly to UV-C irradiation, with higher dosages being required with increasing concentrations of total solids in the human milk sample. The decimal reduction dosage was 289±17 and 945±164 J/l for total solids of 107 and 146 g/l, respectively. No significant changes in the fatty acid profile, BSSL activity or ALP activity were observed up to the dosage required for a 5-log10 reduction of the five species of bacteria. Conclusion UV-C irradiation is capable of reducing vegetative bacteria in human milk to the requirements of milk bank guidelines with no loss of BSSL and ALP activity and no change of FA. PMID:23840820
-
Ultraviolet-C Irradiation: A Novel Pasteurization Method for Donor Human Milk.
Christen, Lukas; Lai, Ching Tat; Hartmann, Ben; Hartmann, Peter E; Geddes, Donna T
2013-01-01
Holder pasteurization (milk held at 62.5°C for 30 minutes) is the standard treatment method for donor human milk. Although this method of pasteurization is able to inactivate most bacteria, it also inactivates important bioactive components. Therefore, the objective of this study was to investigate ultraviolet irradiation as an alternative treatment method for donor human milk. Human milk samples were inoculated with five species of bacteria and then UV-C irradiated. Untreated and treated samples were analysed for bacterial content, bile salt stimulated lipase (BSSL) activity, alkaline phosphatase (ALP) activity, and fatty acid profile. All five species of bacteria reacted similarly to UV-C irradiation, with higher dosages being required with increasing concentrations of total solids in the human milk sample. The decimal reduction dosage was 289±17 and 945±164 J/l for total solids of 107 and 146 g/l, respectively. No significant changes in the fatty acid profile, BSSL activity or ALP activity were observed up to the dosage required for a 5-log10 reduction of the five species of bacteria. UV-C irradiation is capable of reducing vegetative bacteria in human milk to the requirements of milk bank guidelines with no loss of BSSL and ALP activity and no change of FA.
-
Antimicrobial Activity of a Novel Vascular Access Film Dressing Containing Chlorhexidine Gluconate
Wibaux, Anne; Thota, Priyaleela; Mastej, Jozef; Prince, Daniel L.; Carty, Neal; Johnson, Peter
2015-01-01
Background Covering insertion sites with chlorhexidine impregnated dressings has been proven to be clinically effective in reducing catheter related blood stream infections (CR-BSI). Two chlorhexidine gluconate (CHG)-impregnated dressings are commercially available, a polyurethane foam disk and a film dressing containing a chlorhexidine gluconate-impregnated gel pad. While both have demonstrated efficacy in clinical settings, the major drawback of high cost and impaired IV insertion site visibility limits their usage. A new, simple film dressing containing CHG within its adhesive layer is now available. The objective of this study was to test the in vitro antimicrobial efficacy of the new dressing in comparison to the CHG-impregnated gel dressing. Methods Quantitative aliquots of suspensions (concentration of 1.0x106 to 5.0x106 cfu/sample) of clinically relevant challenge organisms (Staphylococcus species, gram-negative bacilli, Candida albicans) were incubated in contact with the new CHG-containing film dressing, a placebo version of the same (negative control) and the commercially available CHG-impregnated gel dressing (positive control). Serial dilutions of the surviving organisms were quantified using the pour plate after 1, 3, 5, and 7 days of incubation in order to calculate an antimicrobial log10 reduction for each organism/dressing combination at each point in time. Results The new CHG-containing film dressing delivered greater than 5.0 log10 reduction throughout the 7 days on all aerobic gram-negative bacilli and Staphylococcus species tested. As of day 1 the CHG-containing film dressing provided greater than 5.0 log10 reduction on Candida albicans. There were no statistically significant differences in the log10 reduction between the two dressings tested. Conclusion The new CHG-containing film dressing was found to be as effective as the chlorhexidine gluconate-impregnated gel dressing on clinically relevant microbes. PMID:26599087
-
Effectiveness of Liquid Soap and Hand Sanitizer against Norwalk Virus on Contaminated Hands▿
Liu, Pengbo; Yuen, Yvonne; Hsiao, Hui-Mien; Jaykus, Lee-Ann; Moe, Christine
2010-01-01
Disinfection is an essential measure for interrupting human norovirus (HuNoV) transmission, but it is difficult to evaluate the efficacy of disinfectants due to the absence of a practicable cell culture system for these viruses. The purpose of this study was to screen sodium hypochlorite and ethanol for efficacy against Norwalk virus (NV) and expand the studies to evaluate the efficacy of antibacterial liquid soap and alcohol-based hand sanitizer for the inactivation of NV on human finger pads. Samples were tested by real-time reverse transcription-quantitative PCR (RT-qPCR) both with and without a prior RNase treatment. In suspension assay, sodium hypochlorite concentrations of ≥160 ppm effectively eliminated RT-qPCR detection signal, while ethanol, regardless of concentration, was relatively ineffective, giving at most a 0.5 log10 reduction in genomic copies of NV cDNA. Using the American Society for Testing and Materials (ASTM) standard finger pad method and a modification thereof (with rubbing), we observed the greatest reduction in genomic copies of NV cDNA with the antibacterial liquid soap treatment (0.67 to 1.20 log10 reduction) and water rinse only (0.58 to 1.58 log10 reduction). The alcohol-based hand sanitizer was relatively ineffective, reducing the genomic copies of NV cDNA by only 0.14 to 0.34 log10 compared to baseline. Although the concentrations of genomic copies of NV cDNA were consistently lower on finger pad eluates pretreated with RNase compared to those without prior RNase treatment, these differences were not statistically significant. Despite the promise of alcohol-based sanitizers for the control of pathogen transmission, they may be relatively ineffective against the HuNoV, reinforcing the need to develop and evaluate new products against this important group of viruses. PMID:19933337
-
Liu, Chuhan; Huang, Yaoxin; Chen, Haiqiang
2015-07-01
Ultraviolet light (UV) has antimicrobial effects, but the shadowing effect has limited its application. In this study, a novel setup using UV processing in agitated water was developed to inactivate Escherichia coli O157:H7 and Salmonella on blueberries. Blueberries were dip- or spot-inoculated with E. coli or Salmonella. Blueberries inoculated with E. coli were treated for 2 to 10 min with UV directly (dry UV) or immersed in agitated water during UV treatment (wet UV). E. coli was most easily killed on spot-inoculated blueberries with a 5.2-log reduction after 10-min wet UV treatment. Dip-inoculated blueberries were the most difficult to be decontaminated with only 1.6-log reduction after 10-min wet UV treatment. Wet UV treatment generally showed higher efficacies than dry UV treatment, achieving an average of 1.4 log more reduction for spot-inoculated blueberries. For dip-inoculated blueberries, chlorine washing and UV treatments were less effective, achieving <2 log reductions of E. coli. Thus, the efficacy of combinations of wet UV with sodium dodecyl sulfate (SDS), levulinic acid, or chlorine was evaluated. Inoculated blueberries were UV-treated while being immersed in agitated water containing 100 ppm SDS, 0.5% levulinic acid or 10 ppm chlorine. The 3 chemicals did not significantly enhance the wet UV treatment. Findings of this study suggest that UV treatment could be used as an alternative to chlorine washing for blueberries and potentially for other fresh produce. A novel UV light system for decontamination of blueberries in water was developed and evaluated. Results demonstrated that the decontamination efficacy of this system was generally as effective as chlorine washing, indicating that it could potentially be used as an alternative to chlorine washing for blueberries and other fresh produce. © 2015 Institute of Food Technologists®
-
Bhaduri, Saumya; Cottrell, Bryan
2004-12-01
Campylobacter jejuni is prevalent in poultry, but the effect of combined refrigerated and frozen storage on its survival, conditions relevant to poultry processing and storage, has not been evaluated. Therefore, the effects of refrigeration at 4 degrees C, freezing at -20 degrees C, and a combination of refrigeration and freezing on the survival of C. jejuni in ground chicken and on chicken skin were examined. Samples were enumerated using tryptic soy agar containing sheep's blood and modified cefoperazone charcoal deoxycholate agar. Refrigerated storage alone for 3 to 7 days produced a reduction in cell counts of 0.34 to 0.81 log10 CFU/g in ground chicken and a reduction in cell counts of 0.31 to 0.63 log10 CFU/g on chicken skin. Declines were comparable for each sample type using either plating medium. Frozen storage, alone and with prerefrigeration, produced a reduction in cell counts of 0.56 to 1.57 log10 CFU/g in ground chicken and a reduction in cell counts of 1.38 to 3.39 log10 CFU/g on chicken skin over a 2-week period. The recovery of C. jejuni following freezing was similar on both plating media. The survival following frozen storage was greater in ground chicken than on chicken skin with or without prerefrigeration. Cell counts after freezing were lower on chicken skin samples that had been prerefrigerated for 7 days than in those that had been prerefrigerated for 0, 1, or 3 days. This was not observed for ground chicken samples, possibly due to their composition. C. jejuni survived storage at 4 and -20 degrees C with either sample type. This study indicates that, individually or in combination, refrigeration and freezing are not a substitute for safe handling and proper cooking of poultry.
-
Yemmireddy, Veerachandra K; Hung, Yen-Con
2015-07-02
The purpose of this study was to determine the effect of food processing organic matter on photocatalytic bactericidal activity of titanium dioxide (TiO2) nanoparticles (NPs). Produce and meat processing wash solutions were prepared using romaine lettuce and ground beef samples. Physico-chemical properties such as pH, turbidity, chemical oxygen demand (COD), total phenolics (for produce) and protein (for meat) content of the extracts were determined using standard procedures. The photocatalytic bactericidal activity of TiO2 (1 mg/mL) in suspension with or without organic matter against Escherichia coli O157:H7 (5-strain) was determined over a period of 3h. Increasing the concentration of organic matter (either produce or meat) from 0% to 100% resulted in 85% decrease in TiO2 microbicidal efficacy. 'Turbidity, total phenolics, and protein contents in wash solutions had significant effect on the log reduction. Increasing the total phenolics content in produce washes from 20 to 114 mg/L decreased the log reduction from 2.7 to 0.38 CFU/mL, whereas increasing the protein content in meat washes from 0.12 to 1.61 mg/L decreased the log reduction from and 5.74 to 0.87 CFU/mL. Also, a linear correlation was observed between COD and total phenolics as well as COD and protein contents. While classical disinfection kinetic models failed to predict, an empirical equation in the form of "Y=me(nX)" (where Y is log reduction, X is COD, and m and n are reaction rate constants) predicted the disinfection kinetics of TiO2 in the presence of organic matter (R(2)=94.4). This study successfully identified an empirical model with COD as a predictor variable to predict the bactericidal efficacy of TiO2 when used in food processing environment. Copyright © 2015 Elsevier B.V. All rights reserved.
-
Edmonds, Sarah L; Mann, James; McCormack, Robert R; Macinga, David R; Fricker, Christopher M; Arbogast, James W; Dolan, Michael J
2010-12-01
The risk of inadequate hand hygiene in food handling settings is exacerbated when water is limited or unavailable, thereby making washing with soap and water difficult. The SaniTwice method involves application of excess alcohol-based hand sanitizer (ABHS), hand "washing" for 15 s, and thorough cleaning with paper towels while hands are still wet, followed by a standard application of ABHS. This study investigated the effectiveness of the SaniTwice methodology as an alternative to hand washing for cleaning and removal of microorganisms. On hands moderately soiled with beef broth containing Escherichia coli (ATCC 11229), washing with a nonantimicrobial hand washing product achieved a 2.86 (±0.64)-log reduction in microbial contamination compared with the baseline, whereas the SaniTwice method with 62 % ethanol (EtOH) gel, 62 % EtOH foam, and 70 % EtOH advanced formula gel achieved reductions of 2.64 ± 0.89, 3.64 ± 0.57, and 4.61 ± 0.33 log units, respectively. When hands were heavily soiled from handling raw hamburger containing E. coli, washing with nonantimicrobial hand washing product and antimicrobial hand washing product achieved reductions of 2.65 ± 0.33 and 2.69 ± 0.32 log units, respectively, whereas SaniTwice with 62 % EtOH foam, 70 % EtOH gel, and 70 % EtOH advanced formula gel achieved reductions of 2.87 ± 0.42, 2.99 ± 0.51, and 3.92 ± 0.65 log units, respectively. These results clearly demonstrate that the in vivo antibacterial efficacy of the SaniTwice regimen with various ABHS is equivalent to or exceeds that of the standard hand washing approach as specified in the U.S. Food and Drug Administration Food Code. Implementation of the SaniTwice regimen in food handling settings with limited water availability should significantly reduce the risk of foodborne infections resulting from inadequate hand hygiene.
-
NASA Astrophysics Data System (ADS)
Singh, Nepal; Singh, Rakesh K.; Bhunia, Arun K.; Stroshine, Richard L.; Simon, James E.
2001-03-01
There have been numerous studies on effectiveness of different sanitizers for microbial inactivation. However, results obtained from different studies indicate that microorganism cannot be easily removed from fresh cut vegetables because of puncture and cut surfaces with varying surface topographies. In this study, three step disinfection approach was evaluated for inactivation of E. coli O157:H7 on shredded lettuce leaves. Sequential application of thyme oil, ozonated water, and aqueous chlorine dioxide was evaluated in which thyme oil was applied first followed by ozonated water and aqueous chlorine dioxide. Shredded lettuce leaves inoculated with cocktail culture of E. coli O157:H7 (C7927, EDL 933 and 204 P), were washed with ozonated water (15 mg/l for 10min), aqueous chlorine dioxide (10 mg/l,for 10min) and thyme oil suspension (0.1%, v/v for 5min). Washing of lettuce leaves with ozonated water, chlorine dioxide and thyme oil suspension resulted in 0.44, 1.20, and 1.46 log reduction (log10 cfu/g), respectively. However, the sequential treatment achieved approximately 3.13 log reductions (log10 cfu/g). These results demonstrate the efficacy of sequential treatments in decontaminating shredded lettuce leaves containing E. coli O157:H7.
-
Niemira, Brendan A; Sommers, Christopher H; Boyd, Glenn
2003-10-01
Six strains of Salmonella (Anatum F4317, Dublin 15480, Enteritidis 13076, Enteritidis WY15159, Stanley H0588, and Typhimurium 14028) were individually inoculated into orange juice concentrate (OJC) and frozen to -20 degrees C. The frozen samples were treated with 0 (nonirradiated), 0.5, 1.0, or 2.0 kGy of gamma radiation and held frozen for 1 h, and the surviving bacterial population was assessed. The strains showed significant variability in their response to freezing and to freezing in combination with irradiation. The response was dose dependent. Relative to the nonfrozen, nonirradiated control, the reduction following the highest dose (2.0 kGy) ranged from 1.29 log CFU/ml (Salmonella Typhimurium) to 2.17 log CFU/ml (Salmonella Stanley). Samples of OJC inoculated with Salmonella Enteritidis WY15159 and irradiated were stored at -20 degrees C for 1, 2, 7, or 14 days, and the surviving population was determined. Relative to the nonfrozen, nonirradiated control, after 14 days, the population was reduced by 1.2 log CFU/ml in the nonirradiated samples and by 3.3 log CFU/ml following treatment with 2.0 kGy. The combination of frozen storage plus irradiation resulted in greater overall reductions than either process alone.
-
Baysal, Ayse Handan; Molva, Celenk; Unluturk, Sevcan
2013-09-16
In the present study, the effect of short wave ultraviolet light (UV-C) on the inactivation of Alicyclobacillus acidoterrestris DSM 3922 spores in commercial pasteurized white grape and apple juices was investigated. The inactivation of A. acidoterrestris spores in juices was examined by evaluating the effects of UV light intensity (1.31, 0.71 and 0.38 mW/cm²) and exposure time (0, 3, 5, 7, 10, 12 and 15 min) at constant depth (0.15 cm). The best reduction (5.5-log) was achieved in grape juice when the UV intensity was 1.31 mW/cm². The maximum inactivation was approximately 2-log CFU/mL in apple juice under the same conditions. The results showed that first-order kinetics were not suitable for the estimation of spore inactivation in grape juice treated with UV-light. Since tailing was observed in the survival curves, the log-linear plus tail and Weibull models were compared. The results showed that the log-linear plus tail model was satisfactorily fitted to estimate the reductions. As a non-thermal technology, UV-C treatment could be an alternative to thermal treatment for grape juices or combined with other preservation methods for the pasteurization of apple juice. © 2013 Elsevier B.V. All rights reserved.
-
Manufacturing Hardwood Dimension Products Directly from Logs: Potential Opportunities
D. Earl Kline; Wenjie Lin; Philip A. Araman
1993-01-01
When a hardwood log is sawn into lumber, over 16 percent of the volume is converted to sawdust. Furthermore, 12 percent of the log is converted to slabs and 17 percent is converted to edging and trimming pieces, all of which are chipped. Hence, less than 55 percent of the log is actually converted to lumber. Lumber must meet the requirements of specific NHLA grades and...
-
Defects in Hardwood Veneer Logs: Their Frequency and Importance
E.S. Harrar
1954-01-01
Most southern hardwood veneer and plywood plants have some method of classifying logs by grade to control the purchase price paid for logs bought on the open market. Such log-grading systems have been developed by experience and are dependent to a large extent upon the ability of the grader and his knowledge of veneer grades and yields required for the specific product...
-
Ultrafast CT scanning of an oak log for internal defects
Francis G. Wagner; Fred W. Taylor; Douglas S. Ladd; Charles W. McMillin; Fredrick L. Roder
1989-01-01
Detecting internal defects in sawlogs and veneer logs with computerized tomographic (CT) scanning is possible, but has been impractical due to the long scanning time required. This research investigated a new scanner able to acquire 34 cross-sectional log scans per second. This scanning rate translates to a linear log feed rate of 85 feet (25.91 m) per minute at one...
-
Reduction of Legionella spp. in Water and in Soil by a Citrus Plant Extract Vapor
Kurzbach, Elena; Score, Jodie; Tejpal, Jyoti; Chi Tangyie, George; Phillips, Carol
2014-01-01
Legionnaires' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml−1 on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml−1 reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml−1 reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources. PMID:25063652
-
Niemira, Brendan A; Sites, Joseph
2008-07-01
Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley on agar plates and inoculated onto the surfaces of Golden Delicious apples. This novel sanitizing technology inactivated both pathogens on agar plates, with higher flow rate (40 liters/min) observed to be more efficacious than were lower flow rates (20 liters/min), irrespective of treatment time (1 or 2 min). Golden Delicious apples were treated with various flow rates (10, 20, 30, or 40 liters/min) of cold plasma for various times (1, 2, or 3 min), applied to dried spot inoculations. All treatments resulted in significant (P < 0.05) reductions from the untreated control, with 40 liters/min more effective than were lower flow rates. Inactivation of Salmonella Stanley followed a time-dependent reduction for all flow rates. Reductions after 3 min ranged from 2.9 to 3.7 log CFU/ml, close to the limit of detection. For E. coli O157:H7, 40 liters/min gave similar reductions for all treatment times, 3.4 to 3.6 log CFU/ml. At lower flow rates, inactivation was related to exposure time, with 3 min resulting in reductions of 2.6 to 3 log CFU/ml. Temperature increase of the treated apples was related to exposure time for all flow rates. The maximum temperature of any plasma-treated apple was 50.8 degrees C (28 degrees C above ambient), after 20 liters/min for 3 min, indicating that antimicrobial effects were not the result of heat. These results indicate that cold plasma is a nonthermal process that can effectively reduce human pathogens inoculated onto fresh produce.
-
Reduction of Legionella spp. in water and in soil by a citrus plant extract vapor.
Laird, Katie; Kurzbach, Elena; Score, Jodie; Tejpal, Jyoti; Chi Tangyie, George; Phillips, Carol
2014-10-01
Legionnaires' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml(-1) on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml(-1) reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml(-1) reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
-
Validation of a 2 percent lactic acid antimicrobial rinse for mobile poultry slaughter operations.
Killinger, Karen M; Kannan, Aditi; Bary, Andy I; Cogger, Craig G
2010-11-01
Poultry processing antimicrobial interventions are critical for pathogen control, and organic, mobile operations in Washington seek alternatives to chlorine. Laboratory and field studies (three replications each) evaluated lactic acid efficacy as a chlorine alternative. For the laboratory study, retail-purchased, conventionally processed chicken wings inoculated with Salmonella were randomly assigned to the following treatments: Salmonella inoculation followed by no treatment (10 wings) or by 3-min rinses of water, 50 to 100 ppm of chlorine, or 2% lactic acid (20 wings for each rinse treatment). Wings were sampled for Salmonella enumeration on xylose lysine desoxycholate agar. During pastured poultry processing at mobile slaughter units for each field study replication, 20 chicken carcasses were randomly assigned to each treatment: untreated control or 3-min immersion in lactic acid or chlorine. Whole-carcass rinses were examined for aerobic plate count (APC) on tryptic soy agar and coliforms on violet red bile agar. Untreated controls were also examined for Salmonella. In the laboratory study, lactic acid produced a significant (P < 0.01) Salmonella reduction compared with the inoculated no-rinse, water, and chlorine treatments, which were statistically similar to each other. In the field study, no Salmonella was detected on untreated controls. Lactic acid produced significant >2-log (P < 0.01) reductions in APC and coliforms, whereas chlorine resulted in slight, but significant 0.4-log reductions (P < 0.01) and 0.21-log reductions (P < 0.05) in APC and coliforms compared with untreated controls. Considering laboratory and field studies, lactic acid produced greater reductions in Salmonella, APC, and coliforms, validating its effectiveness as a chlorine alternative in mobile poultry slaughter operations.
-
Romaniuk, Maria Albertina; Frasch, Alberto Carlos; Cassola, Alejandro
2018-06-01
Trypanosomes, protozoan parasites of medical importance, essentially rely on post-transcriptional mechanisms to regulate gene expression in insect vectors and vertebrate hosts. RNA binding proteins (RBPs) that associate to the 3'-UTR of mature mRNAs are thought to orchestrate master developmental programs for these processes to happen. Yet, the molecular mechanisms by which differentiation occurs remain largely unexplored in these human pathogens. Here, we show that ectopic inducible expression of the RBP TcUBP1 promotes the beginning of the differentiation process from non-infective epimastigotes to infective metacyclic trypomastigotes in Trypanosoma cruzi. In early-log epimastigotes TcUBP1 promoted a drop-like phenotype, which is characterized by the presence of metacyclogenesis hallmarks, namely repositioning of the kinetoplast, the expression of an infective-stage virulence factor such as trans-sialidase, increased resistance to lysis by human complement and growth arrest. Furthermore, TcUBP1-ectopic expression in non-infective late-log epimastigotes promoted full development into metacyclic trypomastigotes. TcUBP1-derived metacyclic trypomastigotes were infective in cultured cells, and developed normally into amastigotes in the cytoplasm. By artificial in vivo tethering of TcUBP1 to the 3' untranslated region of a reporter mRNA we were able to determine that translation of the reporter was reduced by 8-fold, while its mRNA abundance was not significantly compromised. Inducible ectopic expression of TcUBP1 confirmed its role as a translational repressor, revealing significant reduction in the translation rate of multiple proteins, a reduction of polysomes, and promoting the formation of mRNA granules. Expression of TcUBP1 truncated forms revealed the requirement of both N and C-terminal glutamine-rich low complexity sequences for the development of the drop-like phenotype in early-log epimastigotes. We propose that a rise in TcUBP1 levels, in synchrony with nutritional deficiency, can promote the differentiation of T. cruzi epimastigotes into infective metacyclic trypomastigotes.
-
Zanetti, F; De Luca, G; Sacchetti, R; Stampi, S
2007-11-01
The aim of the study was to assess the efficiency of low doses of peracetic acid against viral and bacterial indicators in wastewater and to evaluate if the treatment allows regulatory requirements to be satisfied. A total of 31 samplings were carried out, each involving the collection of secondary effluent and of effluent disinfected with 1.2 or 1.5 mg l(-1) of peracetic acid (contact time 20 minutes). In each sample were measured: somatic coliphages, F-specific RNA bacteriophages, Escherichia coli, total and faecal coliforms, enterococci. Peracetic acid disinfection showed significant differences between the reductions of the microorganisms tested: E. coli showed the highest reduction (1.78 and 2.43 Log respectively with 1.2 and 1.5 mg l(-1) of peracetic acid) and phages the lowest (ranging between 0.52 and 0.60 Log). Only a concentration of 1.5 mg l(-1) of peracetic acid would enable the effluent to be discharged into surface waters in compliance with Italian regulations. The variability of microbial resistance against the peracetic acid disinfection treatment, underlines the importance of assessing disinfection efficiency by using more than one indicator microorganism. The detection of E. coli could be usefully accompanied by tests for more resistant microorganisms such as enterococci or coliphages. In conclusion, peracetic acid can be used for the disinfection of effluents even at low doses, with the advantage of reducing costs and preventing the formation of significant amounts of genotoxic by-products.
-
Arroyo, Cristina; Dorozko, Anna; Gaston, Edurne; O'Sullivan, Michael; Whyte, Paul; Lyng, James G
2017-10-01
This study evaluates the potential of continuous wave Ultraviolet C light (UV-C) and broad-spectrum intense pulsed light (in this study referred to as High Intensity Light Pulses, HILP) for the inactivation of pathogens of public concern in powdered infant formula (PIF) producers. To achieve this goal a sequential set of experiments were performed, firstly in clear liquid media, secondly on the surface of spherical beads under agitation and, finally in PIF. L. innocua was the most sensitive microorganism to both technologies under all conditions studied with reductions exceeding 4 log 10 cycles in PIF. In the clear liquid medium, the maximum tolerance to light was observed for C. sakazakii against UV-C light and for B. subtilis spores against HILP, with a fluence of approximately 17 mJ/cm 2 required for a 1 log 10 cycle inactivation (D value) of each species. In PIF it was possible to inactivate >99% of the vegetative cell populations by HILP with a fluence of 199 mJ/cm 2 and of B. subtilis spores by doubling the fluence. By contrast, for UV-C treatments a fluence of 2853 mJ/cm 2 was needed for 99.9% reduction of C. sakazakii, which was the most light-resistant microorganism to UV-C. Results here obtained clearly show the potential for light-based interventions to improve PIF microbiological safety. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
Richter, Katharina; Thomas, Nicky; Claeys, Jolien; McGuane, Jonathan; Prestidge, Clive A; Coenye, Tom; Wormald, Peter-John; Vreugde, Sarah
2017-06-01
Many infectious diseases are associated with multidrug-resistant (MDR) bacteria residing in biofilms that require high antibiotic concentrations. While oral drug delivery is frequently ineffective, topical treatments have the potential to deliver higher drug concentrations to the infection site while reducing systemic side effects. This study determined the antibiofilm activity of a surgical wound gel loaded with the iron chelator deferiprone (Def) and the heme analogue gallium-protoporphyrin (GaPP), alone and in combination with ciprofloxacin. Activity against MDR Staphylococcus aureus , Staphylococcus epidermidis , Pseudomonas aeruginosa , and Acinetobacter johnsonii biofilms was assessed in the colony biofilm and artificial wound model by enumeration of CFU and correlative light/electron microscopy. While Staphylococcus biofilms were equally susceptible to GaPP and Def-GaPP gels (log 10 reduction of 3.8 and 3.7, respectively), the Def-GaPP combination was crucial for significant activity against P. aeruginosa biofilms (log 10 reduction of 1.3 for GaPP and 3.3 for Def-GaPP). When Def-GaPP gel was combined with ciprofloxacin, the efficacy exceeded the activity of the individual compounds. Def-GaPP delivered in a surgical wound gel showed significant antibiofilm activity against different MDR strains and could enhance the gel's wound-healing properties. Moreover, Def-GaPP indicated a potentiation of ciprofloxacin. This antibiofilm strategy has potential for clinical utilization as a therapy for topical biofilm-related infections. Copyright © 2017 American Society for Microbiology.
-
Claeys, Jolien; McGuane, Jonathan; Prestidge, Clive A.; Wormald, Peter-John
2017-01-01
ABSTRACT Many infectious diseases are associated with multidrug-resistant (MDR) bacteria residing in biofilms that require high antibiotic concentrations. While oral drug delivery is frequently ineffective, topical treatments have the potential to deliver higher drug concentrations to the infection site while reducing systemic side effects. This study determined the antibiofilm activity of a surgical wound gel loaded with the iron chelator deferiprone (Def) and the heme analogue gallium-protoporphyrin (GaPP), alone and in combination with ciprofloxacin. Activity against MDR Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Acinetobacter johnsonii biofilms was assessed in the colony biofilm and artificial wound model by enumeration of CFU and correlative light/electron microscopy. While Staphylococcus biofilms were equally susceptible to GaPP and Def-GaPP gels (log10 reduction of 3.8 and 3.7, respectively), the Def-GaPP combination was crucial for significant activity against P. aeruginosa biofilms (log10 reduction of 1.3 for GaPP and 3.3 for Def-GaPP). When Def-GaPP gel was combined with ciprofloxacin, the efficacy exceeded the activity of the individual compounds. Def-GaPP delivered in a surgical wound gel showed significant antibiofilm activity against different MDR strains and could enhance the gel's wound-healing properties. Moreover, Def-GaPP indicated a potentiation of ciprofloxacin. This antibiofilm strategy has potential for clinical utilization as a therapy for topical biofilm-related infections. PMID:28396543
-
15 CFR 762.3 - Records exempt from recordkeeping requirements.
Code of Federal Regulations, 2010 CFR
2010-01-01
...; (2) Special export file list; (3) Vessel log from freight forwarder; (4) Inspection certificate; (5... form; (12) Financial hold form; (13) Export parts shipping problem form; (14) Draft number log; (15) Expense invoice mailing log; (16) Financial status report; (17) Bank release of guarantees; (18) Cash...
-
15 CFR 762.3 - Records exempt from recordkeeping requirements.
Code of Federal Regulations, 2011 CFR
2011-01-01
...; (2) Special export file list; (3) Vessel log from freight forwarder; (4) Inspection certificate; (5... form; (12) Financial hold form; (13) Export parts shipping problem form; (14) Draft number log; (15) Expense invoice mailing log; (16) Financial status report; (17) Bank release of guarantees; (18) Cash...
-
10 CFR 39.65 - Personnel monitoring.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 10 Energy 1 2014-01-01 2014-01-01 false Personnel monitoring. 39.65 Section 39.65 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.65 Personnel monitoring. (a) The licensee may not permit an individual to act as a logging...
-
10 CFR 39.65 - Personnel monitoring.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 10 Energy 1 2011-01-01 2011-01-01 false Personnel monitoring. 39.65 Section 39.65 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.65 Personnel monitoring. (a) The licensee may not permit an individual to act as a logging...
-
10 CFR 39.65 - Personnel monitoring.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 10 Energy 1 2013-01-01 2013-01-01 false Personnel monitoring. 39.65 Section 39.65 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.65 Personnel monitoring. (a) The licensee may not permit an individual to act as a logging...
-
10 CFR 39.65 - Personnel monitoring.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 1 2010-01-01 2010-01-01 false Personnel monitoring. 39.65 Section 39.65 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.65 Personnel monitoring. (a) The licensee may not permit an individual to act as a logging...
-
10 CFR 39.65 - Personnel monitoring.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 10 Energy 1 2012-01-01 2012-01-01 false Personnel monitoring. 39.65 Section 39.65 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Radiation Safety Requirements § 39.65 Personnel monitoring. (a) The licensee may not permit an individual to act as a logging...
-
10 CFR 39.41 - Design and performance criteria for sources.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 39.41 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL... source for use in well logging applications if— (1) The sealed source is doubly encapsulated; (2) The... use in well logging applications if it meets the requirements of USASI N5.10-1968, “Classification of...
-
Shen, Cangliang; Adler, Jeremy M; Geornaras, Ifigenia; Belk, Keith E; Smith, Gary C; Sofos, John N
2010-03-01
This study compared thermal inactivation of Escherichia coli O157:H7 in nonintact beefsteaks of different thicknesses by different cooking methods and appliances. Coarsely ground beef was inoculated with rifampin-resistant E. coli O157:H7 (eight-strain composite, 6 to 7 log CFU/g) and then mixed with sodium chloride (0.45%) plus sodium tripolyphosphate (0.23%); the total water added was 10%. The meat was stuffed into bags (10-cm diameter), semifrozen (-20 degrees C, 6 h), and cut into 1.5-, 2.5-, and 4.0-cm-thick steaks. Samples were then individually vacuum packaged, frozen (-20 degrees C, 42 h), and tempered (4 degrees C, 2.5 h) before cooking. Partially thawed (-2 +/- 1 degrees C) steaks were pan broiled (Presto electric skillet and Sanyo grill), double pan broiled (George Foreman grill), or roasted (Oster toaster oven and Magic Chef standard kitchen oven) to a geometric center temperature of 65 degrees C. Extent of pathogen inactivation decreased in order of roasting (2.0 to 4.2 log CFU/g) > pan broiling (1.6 to 2.8 log CFU/g) >/= double pan broiling (1.1 to 2.3 log CFU/g). Cooking of 4.0-cm-thick steaks required a longer time (19.8 to 65.0 min; variation was due to different cooking appliances), and caused greater reductions in counts (2.3 to 4.2 log CFU/g) than it did in thinner samples (1.1 to 2.9 log CFU/g). The time to reach the target temperature increased in order of George Foreman grill (3.9 to 19.8 min) < Oster toaster oven (11.3 to 45.0 min) < Presto electric skillet (16.3 to 55.0 min) < Sanyo grill (14.3 to 65.0 min) < standard kitchen oven (20.0 to 63.0 min); variation was due to steak thickness. Results indicated that increased steak thickness allowed greater inactivation of E. coli O157:H7, as time to reach the target internal temperature increased. Roasting in a kitchen oven was most effective for pathogen inactivation.
-
NASA Astrophysics Data System (ADS)
Ivanova, G. A.; Conard, S. G.; McRae, D. J.; Kukavskaya, E. A.; Bogorodskaya, A. V.; Kovaleva, N. M.
2010-12-01
Wildfire and large-scale forest harvesting are the two major disturbances in the Russian boreal forests. Non-recovered logged sites total about a million hectares in Siberia. Logged sites are characterized by higher fire hazard than forest sites due to the presence of generally untreated logging slash (i.e., available fuel) which dries out much more rapidly compared to understory fuels. Moreover, most logging sites can be easily accessed by local population; this increases the risk for fire ignition. Fire impacts on the overstory trees, subcanopy woody layer, and ground vegetation biomass were estimated on 14 logged and unlogged comparison sites in the Lower Angara Region in 2009-2010 as part of the NASA-funded NEESPI project, The Influence of Changing Forestry Practices on the Effects of Wildfire and on Interactions Between Fire and Changing Climate in Central Siberia. Based on calculated fuel consumption, we estimated carbon emission from fires on both logged and unlogged burned sites. Carbon emission from fires on logged sites appeared to be twice that on unlogged sites. Soil respiration decreased on both site types after fires. This reduction may partially offset fire-produced carbon emissions. Carbon emissions from fire and post-fire ecosystem damage on logged sites are expected to increase under changing climate conditions and as a result of anticipated increases in future forest harvesting in Siberia.
-
Bilal, Hajira; Peleg, Anton Y; McIntosh, Michelle P; Styles, Ian K; Hirsch, Elizabeth B; Landersdorfer, Cornelia B; Bergen, Phillip J
2018-06-01
To identify the fosfomycin pharmacokinetic (PK)/pharmacodynamic (PD) index (fT>MIC, fAUC/MIC or fCmax/MIC) most closely correlated with activity against Pseudomonas aeruginosa and determine the PK/PD target associated with various extents of bacterial killing and the prevention of emergence of resistance. Dose fractionation was conducted over 24 h in a dynamic one-compartment in vitro PK/PD model utilizing P. aeruginosa ATCC 27853 and two MDR clinical isolates (CR 1005 and CW 7). In total, 35 different dosing regimens were examined across the three strains. Microbiological response was examined by log changes and population analysis profiles. A Hill-type Emax model was fitted to the killing effect data (expressed as the log10 ratio of the area under the cfu/mL curve for treated regimens versus controls). Bacterial killing of no more than ∼3 log10 cfu/mL was achieved irrespective of regimen. The fAUC/MIC was the PK/PD index most closely correlated with efficacy (R2 = 0.80). The fAUC/MIC targets required to achieve 1 and 2 log10 reductions in the area under the cfu/mL curve relative to growth control were 489 and 1024, respectively. No regimen was able to suppress the emergence of resistance, and near-complete replacement of susceptible with resistant subpopulations occurred with virtually all regimens. Bacterial killing for fosfomycin against P. aeruginosa was most closely associated with the fAUC/MIC. Suppression of fosfomycin-resistant subpopulations could not be achieved even with fosfomycin exposures well above those that can be safely achieved clinically.
-
This paper presents risk-based enteric pathogen log reduction targets for non-potable and potable uses of a variety of alternative source waters (i.e., locally-collected greywater, roof runoff, and stormwater). A probabilistic Quantitative Microbial Risk Assessment (QMRA) was use...
-
16. Photocopy of photograph (4 x 5 inch reduction of ...
16. Photocopy of photograph (4 x 5 inch reduction of 1939 3-1/4 x 5-5/8 inch print, photographer unknown; in Recreation files, Supervisor's Office, Mt. Baker-Snoqualmie National Forest) GENERAL VIEW, NORTHEAST CORNER, INTERPRETIVE LOG TO LEFT. - Glacier Ranger Station, Washington State Route 542, Glacier, Whatcom County, WA
-
Effect of the Cedar River on the quality of the ground-water supply for Cedar Rapids, Iowa
Schulmeyer, P.M.
1995-01-01
Above-normal streamflow and precipitation during the study could have increased the effect the river had on the alluvial aquifer and on the possibility of contamination by a pathogen. Microscopic particulate analysis of 29 samples found no Giardia cysts or Crytosporidium oocysts in water collected from municipal wells. Data also indicate that the aquifer is filtering out large numbers of algae, diatoms, rotifers, and nematodes as well as filtering out Cryptosporidium, Giardia, and other protozoa. The number of algae, diatoms, rotifers, protozoa, and vegetative debris for selected municipal wells tested showed at least a reduction to 1 per 1,000 of the number found in the river. A relative risk factor and a log-reduction rate were determined for the aquifer in the vicinity of selected wells. One municipal well had a high-risk factor, three other wells had a moderate-risk factor, and four wells had a low-risk factor. The filtering efficiency of the aquifer is equivalent to a 3 log-reduction rate or 99.99-percent reduction in particulates.
-
Teaching medical students cancer risk reduction nutrition counseling using a multimedia program.
Kolasa, K M; Jobe, A C; Miller, M G; Clay, M C
1999-03-01
There are many barriers to medical students receiving education about the linkage between nutrition and cancer, including the lack of role models and teachers and insufficient curricular time. We tested the use of a multimedia program as a possible solution to teaching diet-risk assessment and counseling skills. Images of Cancer Prevention, The Nutrition Link is a CD-ROM multimedia program that was developed and evaluated by 147 medical students. Pre-use and post-use surveys, computer log files, and recorded response sessions were used to determine the learner's 1) ease in using the program, 2) attitudes about the treatment of the content, 3) knowledge gain, and 4) attitudes about the role of physicians in nutrition assessment and counseling for cancer risk reduction. Students improved their knowledge of dietary guidelines for cancer risk reduction and made positive changes in their attitudes toward the role of physicians in dietary counseling. However, most students reported that they would not use the program unless it was required that they do so. The multimedia program was successful; it affected students' knowledge and attitudes concerning nutrition as a modifiable risk factor for some cancers. In addition, the design and delivery of the multimedia product was positively reviewed by the students for ease of access, message design, individualized instruction, and flexibility. Despite these favorable ratings, it was not clear that students would use the program unless required to do so.
-
ERIC Educational Resources Information Center
Hao, Jiangang; Smith, Lawrence; Mislevy, Robert; von Davier, Alina; Bauer, Malcolm
2016-01-01
Extracting information efficiently from game/simulation-based assessment (G/SBA) logs requires two things: a well-structured log file and a set of analysis methods. In this report, we propose a generic data model specified as an extensible markup language (XML) schema for the log files of G/SBAs. We also propose a set of analysis methods for…
-
Estimating air drying times of small-diameter ponderosa pine and Douglas-fir logs.
William T. Simpson; Xiping. Wang
2003-01-01
Because dense stands of softwood trees are causing forest health problems in the western United States, new ways to use this material need to be found. One option is to use this material as logs rather than sawing it into lumber. For many applications, logs require some degree of drying. Even though these logs may be considered small diameter, they are large compared...
-
Zhuang, Yao; Ren, Hongqiang; Geng, Jinju; Zhang, Yingying; Zhang, Yan; Ding, Lili; Xu, Ke
2015-05-01
This study investigated the inactivation of two antibiotic resistance genes (ARGs)-sul1 and tetG, and the integrase gene of class 1 integrons-intI1 by chlorination, ultraviolet (UV), and ozonation disinfection. Inactivation of sul1, tetG, and intI1 underwent increased doses of three disinfectors, and chlorine disinfection achieved more inactivation of ARGs and intI1 genes (chlorine dose of 160 mg/L with contact time of 120 min for 2.98-3.24 log reductions of ARGs) than UV irradiation (UV dose of 12,477 mJ/cm(2) for 2.48-2.74 log reductions of ARGs) and ozonation disinfection (ozonation dose of 177.6 mg/L for 1.68-2.55 log reductions of ARGs). The 16S rDNA was more efficiently removed than ARGs by ozone disinfection. The relative abundance of selected genes (normalized to 16S rDNA) increased during ozonation and with low doses of UV and chlorine disinfection. Inactivation of sul1 and tetG showed strong positive correlations with the inactivation of intI1 genes (for sul1, R (2) = 0.929 with p < 0.01; for tetG, R (2) = 0.885 with p < 0.01). Compared to other technologies (ultraviolet disinfection, ozonation disinfection, Fenton oxidation, and coagulation), chlorination is an alternative method to remove ARGs from wastewater effluents. At a chlorine dose of 40 mg/L with 60 min contact time, the selected genes inactivation efficiency could reach 1.65-2.28 log, and the cost was estimated at 0.041 yuan/m(3).
-
Sandvik, Elizabeth L.; McLeod, Bruce R.; Parker, Albert E.; Stewart, Philip S.
2013-01-01
The purpose of this study was to investigate the mechanism by which a direct electrical current reduced the viability of Staphylococcus epidermidis biofilms in conjunction with ciprofloxacin at physiologic saline conditions meant to approximate those in an infected artificial joint. Biofilms grown in CDC biofilm reactors were exposed to current for 24 hours in 1/10th strength tryptic soy broth containing 9 g/L total NaCl. Dose-dependent log reductions up to 6.7 log10 CFU/cm2 were observed with the application of direct current at all four levels (0.7 to 1.8 mA/cm2) both in the presence and absence of ciprofloxacin. There were no significant differences in log reductions for wells with ciprofloxacin compared to those without at the same current levels. When current exposures were repeated without biofilm or organics in the medium, significant generation of free chlorine was measured. Free chlorine doses equivalent to the 24 hour endpoint concentration for each current level were shown to mimic killing achieved by current application. Current exposure (1.8 mA/cm2) in medium lacking chloride and amended with sulfate, nitrate, or phosphate as alternative electrolytes produced diminished kills of 3, 2, and 0 log reduction, respectively. Direct current also killed Pseudomonas aeruginosa biofilms when NaCl was present. Together these results indicate that electrolysis reactions generating hypochlorous acid from chloride are likely a main contributor to the efficacy of direct current application. A physiologically relevant NaCl concentration is thus a critical parameter in experimental design if direct current is to be investigated for in vivo medical applications. PMID:23390518
-
Meujo, Damaris A F; Kevin, Dion A; Peng, Jiangnan; Bowling, John J; Liu, Jianping; Hamann, Mark T
2010-03-31
An innovative approach to Post-Harvest Processing (PHP) of oysters is introduced focusing on the effects of supercritical carbon dioxide (scCO(2)) on bacterial contaminants trapped in the digestive system of oysters. Oysters were exposed to scCO(2) under two conditions: (1) 100 bar and 37 degrees C for 30 min and (2) 172 bar and 60 degrees C for 60 min. Using FDA standard guidelines for food analysis, variations in the Aerobic Plate Count (APC) were assessed. It was established that exposing oysters to CO(2) at 100 bar and 37 degrees C for 30 min and at 172 bar and 60 degrees C for 60 min induced 2-log and 3-log reductions in the APC respectively. The decrease in the microbial load as a result of treatment with scCO(2) was found to be significant (P=0.002). A release of adductor muscles from the shell was noted in oysters treated at 172 bar and 60 degrees C for 60 min; this was not the case for oysters treated at 100 bar and 37 degrees C for 30 min. A blind study allowing sensory analysis of treated vs. untreated oysters was also completed and no significant change in the physical appearance, smell, or texture was recorded. In this paper, we also report the effect of scCO(2) on several bacterial isolates, including a referenced ATCC strain of a non-pathogenic Vibrio (Vibrio fischeri) as well as several other bacterial isolates cultured from oyster' tissues and found to share biochemical features common to pathogenic Vibrio strains. A complete inactivation (minimum 7-log reduction) was achieved with these latter bacterial isolates. A 6-log reduction was observed with V. fischeri. Copyright 2009 Elsevier B.V. All rights reserved.
-
Efficacy of feed additives against Campylobacter in live broilers during the entire rearing period.
Guyard-Nicodème, M; Keita, A; Quesne, S; Amelot, M; Poezevara, T; Le Berre, B; Sánchez, J; Vesseur, P; Martín, Á; Medel, P; Chemaly, Marianne
2016-02-01
Poultry meat is the major source of human campylobacteriosis, the most frequently reported zoonosis in the EU. The prevalence of Campylobacter colonization in European broiler flocks is 71%. Despite considerable efforts, there is still no effective strategy available to prevent or reduce Campylobacter colonization in broilers. This study tested a wide variety of feed additives to reduce Campylobacter shedding in primary poultry production. Twelve additives containing organic or fatty acids, monoglycerides, plant extracts, prebiotics, or probiotics were tested. For each additive, broilers contaminated with Campylobacter jejuni were fed with an additive free diet (control group) or with a supplemented diet (treated group) and Campylobacter loads compared at three sampling times. No treatment was able to prevent broiler colonization by Campylobacter, and there was a high degree of variation in contamination among the birds. At 14 d of age, eight treatments significantly decreased the colonization level compared to the control group by a maximum of 2 log10 CFU/g. At 35 d of age, three of these treatments still had a significant effect with a maximum reduction of 1.88 log10 CFU/g for a probiotic. At 42 d of age, only one short-chain fatty acid was still significantly efficient with a mean reduction over 2 log10 CFU/g. In addition, a probiotic and a prebiotic-like compound significantly decreased the contamination by a maximum of 3 log10 CFU/g, only at the 42-d sampling period. This study gives promising results regarding the use of feed additives to reduce Campylobacter infection in flocks. Nevertheless, a global approach, combining intervention measures at the different steps of the broiler meat production chain could have a greater impact on the reduction of public health risk. © 2015 Poultry Science Association Inc.
-
Meujo, Damaris A.F.; Kevin, Dion; Peng, Jiangnan; Bowling, John J.; Liu, Jianping; Hamann, Mark T.
2010-01-01
An innovative approach to Post-Harvest Processing (PHP) of oysters is introduced focusing on the effects of supercritical carbon dioxide (scCO2) on bacterial contaminants trapped in the digestive system of oysters. Oysters were exposed to scCO2 under two conditions: (1) 100 bar and 37 °C for 30 minutes and (2) 172 bar and 60 °C for 60 minutes. Using FDA standard guidelines for food analysis, variations in the Aerobic Plate Count (APC) was assessed. It was established that exposing oysters to CO2 at 100 bar and 37 °C for 30 minutes and at 172 bar and 60°C for 60 minutes induced 2-log and 3-log reductions in the APC respectively. The decrease in the microbial load as a result of treatment with scCO2 was found to be significant (P=0.002). A release of adductor muscles from the shell was noted in oysters treated at 172 bar and 60 °C for 60 minutes; this was not the case for oysters treated at 100 bar and 37 °C for 30 minutes. A blind study allowing sensory analysis of treated vs. untreated oysters was also completed and no significant change in the physical appearance, smell, or texture was recorded. In this paper, we also report the effect of scCO2 on several bacterial isolates, including a referenced ATCC strain of a non pathogenic Vibrio (V. fisherii) as well as several other bacterial isolates cultured from oyster’ tissues and found to share biochemical features common to pathogenic Vibrio strains. A complete inactivation (minimum 7-log reduction) was achieved with these latter bacterial isolates. A 6-log reduction was observed with V. fisherii. PMID:20022650
-
Sandvik, Elizabeth L; McLeod, Bruce R; Parker, Albert E; Stewart, Philip S
2013-01-01
The purpose of this study was to investigate the mechanism by which a direct electrical current reduced the viability of Staphylococcus epidermidis biofilms in conjunction with ciprofloxacin at physiologic saline conditions meant to approximate those in an infected artificial joint. Biofilms grown in CDC biofilm reactors were exposed to current for 24 hours in 1/10(th) strength tryptic soy broth containing 9 g/L total NaCl. Dose-dependent log reductions up to 6.7 log(10) CFU/cm(2) were observed with the application of direct current at all four levels (0.7 to 1.8 mA/cm(2)) both in the presence and absence of ciprofloxacin. There were no significant differences in log reductions for wells with ciprofloxacin compared to those without at the same current levels. When current exposures were repeated without biofilm or organics in the medium, significant generation of free chlorine was measured. Free chlorine doses equivalent to the 24 hour endpoint concentration for each current level were shown to mimic killing achieved by current application. Current exposure (1.8 mA/cm(2)) in medium lacking chloride and amended with sulfate, nitrate, or phosphate as alternative electrolytes produced diminished kills of 3, 2, and 0 log reduction, respectively. Direct current also killed Pseudomonas aeruginosa biofilms when NaCl was present. Together these results indicate that electrolysis reactions generating hypochlorous acid from chloride are likely a main contributor to the efficacy of direct current application. A physiologically relevant NaCl concentration is thus a critical parameter in experimental design if direct current is to be investigated for in vivo medical applications.
-
Hoover, Randall; Marra, Andrea; Duffy, Erin; Cammarata, Sue K
2017-01-01
Abstract Background Delafloxacin (DLX) is a broad-spectrum fluoroquinolone antibiotic under FDA review for the treatment of ABSSSI. Previous studies determined DLX bacterial stasis and 1-log10 bacterial reduction free AUC0-24 / MIC (fAUC0-24/MIC) targets for Escherichia coli (EC) and Pseudomonas aeruginosa (PA) in a mouse thigh infection model. The resulting PK/PD targets were used to predict DLX target attainment probabilities (TAP) in humans. Methods Monte Carlo simulations were used to estimate TAP with DLX 300 mg IV, q12hr. Human DLX plasma pharmacokinetics were determined in patients with ABSSSI in a Phase 3 clinical trial. Individual AUC values were analyzed and determined to be log-normally distributed. The parameters of the AUC distribution were used to simulate random values for fAUC24, which then were combined with random MIC values based on 2014–2015 US distributions of skin and soft tissue isolates of EC (n = 108) and PA (n = 40), to calculate PK/PD TAPs. Results DLX fAUC0-24/MIC targets for bacterial stasis and 1-log10 bacterial reduction for EC were 14.5 and 26.2, and for PA were 3.81 and 5.02, respectively. The Monte Carlo simulations for EC predicted TAPs of 98.7% for stasis at an MIC of 0.25 μg/mL, and 99.3% for 1-log10 bacterial reduction at an MIC of 0.12 μg/mL. The simulations for PA predicted TAPs of 97.3% for stasis and 86.5% for 1-log10 bacterial reduction at an MIC of 1 μg/mL. E. coli MIC (ug/mL) Target 0.008 0.015 0.03 0.06 0.12 0.25 0.5 1 Stasis 100 100 100 100 100 97.8 50.4 2.0 1-Log Kill 100 100 100 100 99.3 60.4 5.8 0.0 P. aeruginosa MIC (ug/mL) Target 0.03 0.06 0.12 0.25 0.5 1 2 4 5 Stasis 100 100 100 100 100 97.3 45.9 1.7 0.5 1-Log Kill 100 100 100 100 100 86.5 17.8 0.3 0.1 Conclusion DLX 300 mg IV, q12hr, should achieve fAUC24/MIC ratios that are adequate to treat ABSSSI caused by most contemporary isolates of EC and PA. For EC, isolates with DLX MICs ≤0.25 μg/mL comprised 73% of all isolates. For PA, isolates with DLX MICs ≤1 μg/mL comprised 88% of all isolates. Similar results would be expected for TAP with oral DLX 450 mg, q12hr. Disclosures R. Hoover, Melinta Therapeutics: Consultant, Consulting fee; A. Marra, Melinta Therapeutics: Employee, Salary; E. Duffy, Melinta Therapeutics: Employee, Salary; S. K. Cammarata, Melinta Therapeutics: Employee, Salary
-
Desroche, N; Dropet, C; Janod, P; Guzzo, J
2016-10-02
This study was designed to evaluate the antibacterial activity of a wound dressing which combines polyacrylate fibres and a silver lipido-colloid matrix (UrgoClean Ag, silver polyabsorbent dressing), against biofilm of methicillin-resistant Staphylococcus aureus (MRSA). Samples of silver polyabsorbent dressing and the neutral form of this dressing (UrgoClean) were applied to biofilms of MRSA formed on a collagen I-coated surface, cultured for 24 hours. Different exposure times were tested (1, 2, 4 and 7 days) without dressing change. The biofilm reduction was quantified by using culture methods and by confocal laser scanning microscopy experiments. The application of the silver polyabsorbent dressing resulted in a significant decrease of the biofilm population by a log reduction of 4.6, after 24 hours of exposure. Moreover, the antibiofilm activity was maintained for 7 days with reduction values up to 4 log (reduction of biofilm superior to 99.99%). The application of the neutral dressing also induced a significant reduction of the concentration of sessile cells after 1 day (about 0.90 log). The results obtained with this neutral form of the dressing showed that the polyacrylate fibres were able to exert a mechanical disruption of the biofilm architecture. These in vitro experiments demonstrated that silver polyabsorbent dressing was able to strongly reduce the biofilm of MRSA. The antibiofilm mechanism of this dressing can be explained by a dual action of the polyabsorbent fibres (based on ammonium polyacrylate polymer around an acrylic core) which induced a mechanical disruption of the biofilm matrix and/or a sequestration of sessile cells, and the diffusion of silver ions which produced bactericidal activity. This study was supported by Laboratoires Urgo (Dijon). P. Janod is an employee of Laboratoires Urgo. The company had no influence on the experimental design and the interpretation of the results.
-
Remis, Melissa J; Jost Robinson, Carolyn A
2012-07-01
This article explores spatial and temporal changes in diurnal primate abundance and behavior in response to hunting, logging, and conservation at the Dzanga Sangha Dense Forest Reserve (RDS), Central African Republic over time. We use a combination of line-transect surveys in 2002 and 2009 (N = 540 km) and ethnographic interviews (N = 210) to investigate changes in the status of cercopithecines and colobines at RDS, with additional comparisons to earlier work. This protected area was lightly logged in the 1970s and the park was gazetted in 1990, with multiple-use reserve sectors allocated. Since the park's inception, hunting and the trade of primates have increased, along with human migration, greater accessibility of arms, and reduction of preferred ungulate prey. Primates have declined in both the park and reserve sectors. Our data further suggest that at RDS hunting has had a greater impact on primate diversity and abundance than logging. We have identified changes in species-specific vulnerability to hunting over time, with Cercopithecus nictitans and Lophocebus albigena initially having appeared to be relatively resistant to hunting pressure in 2002. However, subsequently as gun hunting has increased at RDS, these species have become vulnerable. Although monkeys at RDS have been responding behaviorally to increased gun hunting, they are not able to keep pace with changing hunting practices. This study allows us to begin to understand synergistic impacts of hunting and logging, necessary if we are to recommend strategies to better secure the future of primates in multiuse protected areas. © 2012 Wiley Periodicals, Inc.
-
Disinfection of iceberg lettuce by titanium dioxide-UV photocatalytic reaction.
Kim, Youngbong; Choi, Yoonjung; Kim, Soohyun; Park, Jonghyun; Chung, Myongsoo; Song, Kyung Bin; Hwang, Ingyun; Kwon, Kisung; Park, Jiyong
2009-09-01
Securing the physical quality and microbial safety of fresh foods has been a major focus in the food industry. To improve quality and increase the shelf life of fresh produce, disinfection methods have been developed. Titanium dioxide (TiO2) photocatalytic reactions under UV radiation produce hydroxyl radicals that can be used for disinfection of foodborne pathogenic bacteria. We investigated the effects of TiO2-UV photocatalytic disinfection on the shelf life of iceberg lettuce. Counts of natural microflora (total aerobic bacteria, coliforms, psychrotrophic bacteria, and yeasts and molds) and inoculated pathogenic bacteria (Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and Salmonella Typhimurium) on iceberg lettuce were determined after 20-min treatments with TiO2-UV, UV radiation, a sodium hypochlorite (NaOCl) solution, and tap water. TiO2-UV treatment reduced the number of microorganisms by 1.8 to 2.8 log CFU/g compared with reductions of 0.9 to 1.4 and 0.7 to 1.1 log CFU/g obtained with UV radiation and NaOCl treatments, respectively. Treatment with tap water was used as a control and resulted in no reductions. Counts of microflora for iceberg lettuce at 4 and 25 degrees C were determined during a 9-day period. TiO2-UV treatment resulted in 1.2- and 4.3-log increases in the counts of total aerobic bacteria at 4 and 25 degrees C, respectively, compared with 1.3- to 1.6-log and 4.4- to 4.8-log increases due to UV radiation and NaOCl treatments.
-
Sanitizing in Dry-Processing Environments Using Isopropyl Alcohol Quaternary Ammonium Formula.
Kane, Deborah M; Getty, Kelly J K; Mayer, Brian; Mazzotta, Alejandro
2016-01-01
Dry-processing environments are particularly challenging to clean and sanitize because introduced water can favor growth and establishment of pathogenic microorganisms such as Salmonella. Our objective was to determine the efficacy of an isopropyl alcohol quaternary ammonium (IPAQuat) formula for eliminating potential Salmonella contamination on food contact surfaces. Clean stainless steel coupons and conveyor belt materials used in dry-processing environments were spot inoculated in the center of coupons (5 by 5 cm) with a six-serotype composite of Salmonella (approximately 10 log CFU/ml), subjected to IPAQuat sanitizer treatments with exposure times of 30 s, 1 min, or 5 min, and then swabbed for enumeration of posttreatment survivors. A subset of inoculated surfaces was soiled with a breadcrumb-flour blend and allowed to sit on the laboratory bench for a minimum of 16 h before sanitation. Pretreatment Salmonella populations (inoculated controls, 0 s treatment) were approximately 7.0 log CFU/25 cm(2), and posttreatment survivors were 1.31, 0.72, and < 0.7 (detection limit) log CFU/25 cm(2) after sanitizer exposure for 30 s, 1 min, or 5 min, respectively, for both clean (no added soil) and soiled surfaces. Treatment with the IPAQuat formula using 30-s sanitizer exposures resulted in 5.68-log reductions, whereas >6.0-log reductions were observed for sanitizer exposures of 1 and 5 min. Because water is not introduced into the processing environment with this approach, the IPAQuat formula could have sanitation applications in dry-processing environments to eliminate potential contamination from Salmonella on food contact surfaces.
-
Functional changes after treatment of optic pathway paediatric low-grade gliomas
Magli, A; Forte, R; Cinalli, G; Esposito, F; Parisi, S; Capasso, M; Papparella, A
2013-01-01
Objective To evaluate the functional changes after treatment of paediatric optic pathway gliomas (OPGs). Methods All patients with monofocal OPG seen from January 2004 to January 2011 were included. Best corrected visual acuity (BCVA, LogMAR), contrast sensitivity (Hiding-Heidi low-contrast ‘face' test (HH) and Pelli−Robson (PR) contrast sensitivity test), and the Color Test (Ishihara plate) were obtained. Results Twenty-one patients (10 boys and 11 girls with a mean age of 5.5±4.4 years at diagnosis) were included in the study. Neurofibromatosis was present in four cases. Eighteen patients (85.7%) were treated with initial surgery and three patients (14.3%) with initial chemotherapy. BCVA was 0.67±0.8 LogMAR at baseline and 0.62±0.9 LogMAR at last visit (P=0.41). The Color test was not significantly changed at last visit (P=0.62). Contrast sensitivity with the HH test was 9.1±11.1% at baseline and 3.8±6.4% at last visit (P=0.03). Contrast sensitivity with PR chart was 1.33±0.9log at baseline and 1.05±0.7 log at last visit (P=0.005). A reduction in contrast sensitivity at both tests was significantly greater in patients who relapsed than in patients who did not relapse (P=0.001). Conclusion After the treatment of paediatric optic pathway low-grade gliomas, a reduction in contrast sensitivity during follow-up was observed and may be correlated with tumour relapses. PMID:23970029
-
Silver nanoparticle-E. coli colloidal interaction in water and effect on E. coli survival.
Dror-Ehre, A; Mamane, H; Belenkova, T; Markovich, G; Adin, A
2009-11-15
Silver nanoparticles exhibit antibacterial properties via bacterial inactivation and growth inhibition. The mechanism is not yet completely understood. This work was aimed at elucidating the effect of silver nanoparticles on inactivation of Escherichia coli, by studying particle-particle interactions in aqueous suspensions. Stable, molecularly capped, positively or negatively charged silver nanoparticles were mixed at 1 to 60microgmL(-1) with suspended E. coli cells to examine their effect on inactivation of the bacteria. Gold nanoparticles with the same surfactant were used as a control, being of similar size but made up of a presumably inert metal. Log reduction of 5log(10) and complete inactivation were obtained with the silver nanoparticles while the gold nanoparticles did not show any inactivation ability. The effect of molecularly capped nanoparticles on E. coli survival was dependent on particle number. Log reduction of E. coli was associated with the ratio between the number of nanoparticles and the initial bacterial cell count. Electrostatic attraction or repulsion mechanisms in silver nanoparticle-E. coli cell interactions did not contribute to the inactivation process.
-
Zimoch-Korzycka, Anna; Jarmoluk, Andrzej
2017-03-02
The objectives of this study were to optimize the composition of edible food coatings and to extend the shelf-life of pork meat. Initially, nine meat samples were coated with solutions containing chitosan and hydroxypropyl methylcellulose at various cellulase concentrations: 0%, 0.05%, and 0.1%, stored for 0, 7, and 14 days. Uncoated meat served as the controls. The samples were tested for pH, water activity (a w ), total number of microorganisms (TNM), psychrotrophs (P), number of yeast and molds (NYM), colour, and thiobarbituric acid-reactive substances (TBARS). The pH and a w values varied from 5.42 to 5.54 and 0.919 to 0.926, respectively. The reductions in the TNM, P, and NYM after 14 days of storage were approximately 2.71 log cycles, 1.46 log cycles, and 0.78 log cycles, respectively. The enzyme addition improved the stability of the red colour. Significant reduction in TBARS was noted with the inclusion of cellulase in the coating material. Overall, this study provides a promising alternative method for the preservation of pork meat in industry.
-
Removal of contaminants and pathogens from secondary effluents using intermittent sand filters.
Bali, Mahmoud; Gueddari, Moncef; Boukchina, Rachid
2011-01-01
Intermittent infiltration percolation of wastewater through unsaturated sand bed is an extensive treatment technique aimed at eliminating organic matter, oxidizing ammonium and removing pathogens. The main purpose of this study was to determine the depuration efficiencies of a sand filter to remove contaminants from secondary wastewater effluents. Elimination of pathogenic bacteria (total and faecal coliforms, streptococci) and their relationship with the filter depth were investigated. Results showed a high capacity of infiltration percolation process to treat secondary effluents. Total elimination of suspended solids was obtained. Mean removal rate of BOD(5) and COD was more than 97 and more than 81%, respectively. Other water quality parameters such as NH(4)-N, TKN and PO(4)-P showed significant reduction except NO(3)-N which increased significantly in the filtered water. Efficiency of pathogenic bacteria removal was shown to mainly depend on the filter depth. Average reductions of 2.35 log total coliforms, 2.47 log faecal coliforms and 2.11 log faecal streptococci were obtained. The experimental study has shown the influence of the temperature on the output purification of infiltration percolation process.
-
Afari, George K; Hung, Yen-Con; King, Christopher H
2015-08-01
The objective of this study was to determine the efficacy of neutral pH electrolyzed (NEO) water (155 mg/L free chlorine, pH 7.5) in reducing Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on romaine lettuce, iceberg lettuce, and tomatoes washed in an automated produce washer for different times and washing speeds. Tomatoes and lettuce leaves were spot inoculated with 100 μL of a 5 strain cocktail mixture of either pathogen and washed with 10 or 8 L of NEO water, respectively. Washing lettuce for 30 min at 65 rpm led to the greatest reductions, with 4.2 and 5.9 log CFU/g reductions achieved for E. coli O157:H7 and S. Typhimurium respectively on romaine, whereas iceberg lettuce reductions were 3.2 and 4.6 log CFU/g for E. coli O157:H7 and S. Typhimurium respectively. Washing tomatoes for 10 min at 65 rpm achieved reductions greater than 8 and 6 log CFU/tomato on S. Typhimurium and E. coli O157:H7 respectively. All pathogens were completely inactivated in NEO water wash solutions. No detrimental effects on the visual quality of the produce studied were observed under all treatment conditions. Results show the adoption of this washing procedure in food service operations could be useful in ensuring produce safety. © 2015 Institute of Food Technologists®
-
Bhagat, Arpan; Mahmoud, Barakat S M; Linton, Richard H
2011-01-01
Microorganisms, including pathogens of public health significance, have been shown to contaminate orange juice during the mechanical extraction of juice. The problem gets exacerbated when washed oranges have high initial microbial load, due to an insufficient postharvest treatment. The objective of this study was to investigate the reduction of Salmonella enterica on orange surfaces using ClO₂ gas treatments to achieve a 5 log reduction, consistent with the recommendations of the U.S. Department of Agriculture-National Advisory Committee on Microbiological Criteria for Foods. A mixed culture of four Salmonella strains, isolated from previous orange juice outbreaks, was spot inoculated onto orange skin surface areas. The oranges were then treated with 0.1, 0.3, and 0.5 mg/L ClO₂ gas for 2-14 minutes at 22°C and 90%-95% relative humidity. Surviving bacteria on treated areas were recovered and enumerated over treatment time on a nonselective medium, tryptic soy agar, followed by culturing onto a selective medium, xylose lysine deoxycholate agar. A >5 log reduction of Salmonella per sample of orange surface was observed with 0.1 and 0.3 mg/L ClO₂ gas treatments at 14 minutes and a similar log reduction was observed at 0.5 mg/L ClO₂ gas at 10 minutes. This result demonstrates that the treatment of oranges with ClO₂ gas is a promising technology that could be successfully employed for the treatment of whole oranges to reduce the risk of Salmonella outbreaks in orange juice.
-
Residual Viral and Bacterial Contamination of Surfaces after Cleaning and Disinfection
Tuladhar, Era; Hazeleger, Wilma C.; Koopmans, Marion; Zwietering, Marcel H.; Beumer, Rijkelt R.
2012-01-01
Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses, rotavirus, poliovirus, parechovirus, adenovirus, influenza virus, Staphylococcus aureus, and Salmonella enterica from artificially contaminated stainless steel surfaces. After a single wipe with water, liquid soap, or 250-ppm free chlorine solution, the numbers of infective viruses and bacteria were reduced by 1 log10 for poliovirus and close to 4 log10 for influenza virus. There was no significant difference in residual contamination levels after wiping with water, liquid soap, or 250-ppm chlorine solution. When a single wipe with liquid soap was followed by a second wipe using 250- or 1,000-ppm chlorine, an extra 1- to 3-log10 reduction was achieved, and except for rotavirus and norovirus genogroup I, no significant additional effect of 1,000 ppm compared to 250 ppm was found. A reduced correlation between reduction in PCR units (PCRU) and reduction in infectious particles suggests that at least part of the reduction achieved in the second step is due to inactivation instead of removal alone. We used data on infectious doses and transfer efficiencies to estimate a target level to which the residual contamination should be reduced and found that a single wipe with liquid soap followed by a wipe with 250-ppm free chlorine solution was sufficient to reduce the residual contamination to below the target level for most of the pathogens tested. PMID:22941071
-
Residual viral and bacterial contamination of surfaces after cleaning and disinfection.
Tuladhar, Era; Hazeleger, Wilma C; Koopmans, Marion; Zwietering, Marcel H; Beumer, Rijkelt R; Duizer, Erwin
2012-11-01
Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses, rotavirus, poliovirus, parechovirus, adenovirus, influenza virus, Staphylococcus aureus, and Salmonella enterica from artificially contaminated stainless steel surfaces. After a single wipe with water, liquid soap, or 250-ppm free chlorine solution, the numbers of infective viruses and bacteria were reduced by 1 log(10) for poliovirus and close to 4 log(10) for influenza virus. There was no significant difference in residual contamination levels after wiping with water, liquid soap, or 250-ppm chlorine solution. When a single wipe with liquid soap was followed by a second wipe using 250- or 1,000-ppm chlorine, an extra 1- to 3-log(10) reduction was achieved, and except for rotavirus and norovirus genogroup I, no significant additional effect of 1,000 ppm compared to 250 ppm was found. A reduced correlation between reduction in PCR units (PCRU) and reduction in infectious particles suggests that at least part of the reduction achieved in the second step is due to inactivation instead of removal alone. We used data on infectious doses and transfer efficiencies to estimate a target level to which the residual contamination should be reduced and found that a single wipe with liquid soap followed by a wipe with 250-ppm free chlorine solution was sufficient to reduce the residual contamination to below the target level for most of the pathogens tested.
-
Federal Register 2010, 2011, 2012, 2013, 2014
2013-12-05
... the Standard, employers must assure that operating and maintenance instructions are available on... writing that a worker/supervisor received the training the Standard requires. Under paragraph (i)(10)(ii... requirements contained in the Logging Operations Standard (29 CFR 1910.266). DATES: Comments must be submitted...
-
Stuart, James Ian; Delport, Johan; Lannigan, Robert; Zahariadis, George
2014-01-01
BACKGROUND: Disease monitoring of viruses using real-time polymerase chain reaction (PCR) requires knowledge of the precision of the test to determine what constitutes a significant change. Calculation of quantitative PCR confidence limits requires bivariate statistical methods. OBJECTIVE: To develop a simple-to-use graphical user interface to determine the uncertainty of measurement (UOM) of BK virus, cytomegalovirus (CMV) and Epstein-Barr virus (EBV) real-time PCR assays. METHODS: Thirty positive clinical samples for each of the three viral assays were repeated once. A graphical user interface was developed using a spreadsheet (Excel, Microsoft Corporation, USA) to enable data entry and calculation of the UOM (according to Fieller’s theorem) and PCR efficiency. RESULTS: The confidence limits for the BK virus, CMV and EBV tests were ∼0.5 log, 0.5 log to 1.0 log, and 0.5 log to 1.0 log, respectively. The efficiencies of these assays, in the same order were 105%, 119% and 90%. The confidence limits remained stable over the linear range of all three tests. DISCUSSION: A >5 fold (0.7 log) and a >3-fold (0.5 log) change in viral load were significant for CMV and EBV when the results were ≤1000 copies/mL and >1000 copies/mL, respectively. A >3-fold (0.5 log) change in viral load was significant for BK virus over its entire linear range. PCR efficiency was ideal for BK virus and EBV but not CMV. Standardized international reference materials and shared reporting of UOM among laboratories are required for the development of treatment guidelines for BK virus, CMV and EBV in the context of changes in viral load. PMID:25285125
-
Stuart, James Ian; Delport, Johan; Lannigan, Robert; Zahariadis, George
2014-07-01
Disease monitoring of viruses using real-time polymerase chain reaction (PCR) requires knowledge of the precision of the test to determine what constitutes a significant change. Calculation of quantitative PCR confidence limits requires bivariate statistical methods. To develop a simple-to-use graphical user interface to determine the uncertainty of measurement (UOM) of BK virus, cytomegalovirus (CMV) and Epstein-Barr virus (EBV) real-time PCR assays. Thirty positive clinical samples for each of the three viral assays were repeated once. A graphical user interface was developed using a spreadsheet (Excel, Microsoft Corporation, USA) to enable data entry and calculation of the UOM (according to Fieller's theorem) and PCR efficiency. The confidence limits for the BK virus, CMV and EBV tests were ∼0.5 log, 0.5 log to 1.0 log, and 0.5 log to 1.0 log, respectively. The efficiencies of these assays, in the same order were 105%, 119% and 90%. The confidence limits remained stable over the linear range of all three tests. A >5 fold (0.7 log) and a >3-fold (0.5 log) change in viral load were significant for CMV and EBV when the results were ≤1000 copies/mL and >1000 copies/mL, respectively. A >3-fold (0.5 log) change in viral load was significant for BK virus over its entire linear range. PCR efficiency was ideal for BK virus and EBV but not CMV. Standardized international reference materials and shared reporting of UOM among laboratories are required for the development of treatment guidelines for BK virus, CMV and EBV in the context of changes in viral load.
-
Schneider, Jochen; Harrasser, Norbert; Tübel, Jutta; Mühlhofer, Heinrich; Pförringer, Dominik; von Deimling, Constantin; Foehr, Peter; Kiefel, Barbara; Krämer, Christina; Stemberger, Axel; Schieker, Matthias
2018-01-01
Background Surgical sutures can promote migration of bacteria and thus start infections. Antiseptic coating of sutures may inhibit proliferation of adhered bacteria and avoid such complications. Objectives This study investigated the inhibition of viable adhering bacteria on novel antimicrobially coated surgical sutures using chlorhexidine or octenidine, a critical factor for proliferation at the onset of local infections. The medical need, a rapid eradication of bacteria in wounds, can be fulfilled by a high antimicrobial efficacy during the first days after wound closure. Methods As a pretesting on antibacterial efficacy against relevant bacterial pathogens a zone of inhibition assay was conducted with middle ranged concentrated suture coatings (22 μg/cm). For further investigation of adhering bacteria in detail the most clinically relevant Staphylococcus aureus (ATCC®49230™) was used. Absorbable braided sutures were coated with chlorhexidine-laurate, chlorhexidine-palmitate, octenidine-laurate, and octenidine-palmitate. Each coating type resulted in 11, 22, or 33 μg/cm drug content on sutures. Scanning electron microscopy (SEM) was performed once to inspect the coating quality and twice to investigate if bacteria have colonized on sutures. Adhesion experiments were assessed by exposing coated sutures to S. aureus suspensions for 3 h at 37°C. Subsequently, sutures were sonicated and the number of viable bacteria released from the suture surface was determined. Furthermore, the number of viable planktonic bacteria was measured in suspensions containing antimicrobial sutures. Commercially available sutures without drugs (Vicryl®, PGA Resorba®, and Gunze PGA), as well as triclosan-containing Vicryl® Plus were used as control groups. Results Zone of inhibition assay documented a multispecies efficacy of novel coated sutures against tested bacterial strains, comparable to most relevant S. aureus over 48 hours. SEM pictures demonstrated uniform layers on coated sutures with higher roughness for palmitate coatings and sustaining integrity of coated sutures. Adherent S. aureus were found via SEM on all types of investigated sutures. The novel antimicrobial sutures showed significantly less viable adhered S. aureus bacteria (up to 6.1 log) compared to Vicryl® Plus (0.5 log). Within 11 μg/cm drug-containing sutures, octenidine-palmitate (OL11) showed the highest number of viable adhered S. aureus (0.5 log), similar to Vicryl® Plus. Chlorhexidine-laurate (CL11) showed the lowest number of S. aureus on sutures (1.7 log), a 1.2 log greater reduction. In addition, planktonic S. aureus in suspensions were highly inhibited by CL11 (0.9 log) represents a 0.6 log greater reduction compared to Vicryl® Plus (0.3 log). Conclusions Novel antimicrobial sutures can potentially limit surgical site infections caused by multiple pathogenic bacterial species. Therefore, a potential inhibition of multispecies biofilm formation is assumed. In detail tested with S. aureus, the chlorhexidine-laurate coating (CL11) best meets the medical requirements for a fast bacterial eradication. This suture coating shows the lowest survival rate of adhering as well as planktonic bacteria, a high drug release during the first–clinically most relevant– 48 hours, as well as biocompatibility. Thus, CL11 coatings should be recommended for prophylactic antimicrobial sutures as an optimal surgical supplement to reduce wound infections. However, animal and clinical investigations are important to prove safety and efficacy for future applications. PMID:29315313
-
Obermeier, Andreas; Schneider, Jochen; Harrasser, Norbert; Tübel, Jutta; Mühlhofer, Heinrich; Pförringer, Dominik; Deimling, Constantin von; Foehr, Peter; Kiefel, Barbara; Krämer, Christina; Stemberger, Axel; Schieker, Matthias; Burgkart, Rainer; von Eisenhart-Rothe, Rüdiger
2018-01-01
Surgical sutures can promote migration of bacteria and thus start infections. Antiseptic coating of sutures may inhibit proliferation of adhered bacteria and avoid such complications. This study investigated the inhibition of viable adhering bacteria on novel antimicrobially coated surgical sutures using chlorhexidine or octenidine, a critical factor for proliferation at the onset of local infections. The medical need, a rapid eradication of bacteria in wounds, can be fulfilled by a high antimicrobial efficacy during the first days after wound closure. As a pretesting on antibacterial efficacy against relevant bacterial pathogens a zone of inhibition assay was conducted with middle ranged concentrated suture coatings (22 μg/cm). For further investigation of adhering bacteria in detail the most clinically relevant Staphylococcus aureus (ATCC®49230™) was used. Absorbable braided sutures were coated with chlorhexidine-laurate, chlorhexidine-palmitate, octenidine-laurate, and octenidine-palmitate. Each coating type resulted in 11, 22, or 33 μg/cm drug content on sutures. Scanning electron microscopy (SEM) was performed once to inspect the coating quality and twice to investigate if bacteria have colonized on sutures. Adhesion experiments were assessed by exposing coated sutures to S. aureus suspensions for 3 h at 37°C. Subsequently, sutures were sonicated and the number of viable bacteria released from the suture surface was determined. Furthermore, the number of viable planktonic bacteria was measured in suspensions containing antimicrobial sutures. Commercially available sutures without drugs (Vicryl®, PGA Resorba®, and Gunze PGA), as well as triclosan-containing Vicryl® Plus were used as control groups. Zone of inhibition assay documented a multispecies efficacy of novel coated sutures against tested bacterial strains, comparable to most relevant S. aureus over 48 hours. SEM pictures demonstrated uniform layers on coated sutures with higher roughness for palmitate coatings and sustaining integrity of coated sutures. Adherent S. aureus were found via SEM on all types of investigated sutures. The novel antimicrobial sutures showed significantly less viable adhered S. aureus bacteria (up to 6.1 log) compared to Vicryl® Plus (0.5 log). Within 11 μg/cm drug-containing sutures, octenidine-palmitate (OL11) showed the highest number of viable adhered S. aureus (0.5 log), similar to Vicryl® Plus. Chlorhexidine-laurate (CL11) showed the lowest number of S. aureus on sutures (1.7 log), a 1.2 log greater reduction. In addition, planktonic S. aureus in suspensions were highly inhibited by CL11 (0.9 log) represents a 0.6 log greater reduction compared to Vicryl® Plus (0.3 log). Novel antimicrobial sutures can potentially limit surgical site infections caused by multiple pathogenic bacterial species. Therefore, a potential inhibition of multispecies biofilm formation is assumed. In detail tested with S. aureus, the chlorhexidine-laurate coating (CL11) best meets the medical requirements for a fast bacterial eradication. This suture coating shows the lowest survival rate of adhering as well as planktonic bacteria, a high drug release during the first-clinically most relevant- 48 hours, as well as biocompatibility. Thus, CL11 coatings should be recommended for prophylactic antimicrobial sutures as an optimal surgical supplement to reduce wound infections. However, animal and clinical investigations are important to prove safety and efficacy for future applications.
-
Effect of storage temperatures and stresses on the survival of Salmonella spp. in halva.
Osaili, T M; Al-Nabulsi, A A; Nazzal, D S; Shaker, R R
2017-11-01
The presence of Salmonella spp. in halva has been associated with foodborne illnesses and product recalls from the markets. This study investigated the effect of environmental stresses on the survival of Salmonella spp. in halva during storage for 12 months at 10 and 25°C (log (N 0 /N) g -1 ). Halva samples were inoculated with a cocktail of four strains of unstressed, desiccation stressed or heat stressed Salmonella (10 6 -10 7 CFU per gram). In general, survival of Salmonella spp. in halva decreased significantly (P ˂ 0·05) as storage time and temperature increased. At the end of halva shelf life at 10°C, the initial populations of unstressed, desiccation stressed or heat stressed Salmonella spp. decreased by 2·7, 2·6 or 2·8 log CFU per gram (reduction rate c. 0·2 log CFU per month), respectively. While at 25°C, the populations decreased 5·2, 6·7 or 6·3 log CFU per gram, respectively (reduction rate c. 0·4-0·5 log CFU per month). The populations of stressed Salmonella spp. in halva samples were not significantly different (P ≥ 0·05) from populations of unstressed cells during storage at 10 and 25°C, except during the last 3 months of storage at 25°C when populations of unstressed cells were higher (P < 0·05). Exposing Salmonella spp. to desiccation or heat stress prior product contamination may play a role in Salmonella spp. survival in halva during storage. Contamination of halva (tahini halva) with Salmonella from raw materials or during production was documented. Halva and tahini have been involved in salmonellosis outbreaks in different countries. The study demonstrated enhanced survivability of stressed and unstressed Salmonella spp. in halva over a 12-month storage period at 10 and 25°C with lower log reductions than expected. Exposing Salmonella spp. to desiccation or heat stress prior product contamination may play a role in microbial survival in halva during storage. These findings serve as a model to halva producers to implement control measures to prevent Salmonella spp. contamination in halva. © 2017 The Society for Applied Microbiology.
-
Bailey, Emily S; Casanova, Lisa M; Simmons, Otto D; Sobsey, Mark D
2018-07-15
Treated wastewater is increasingly of interest for either nonpotable purposes, such as agriculture and industrial use, or as source water for drinking water supplies; however, this type of advanced treatment for water supply is not always possible for many low resource settings. As an alternative, multiple barriers of physical, chemical and biological treatment with lower cost and simpler operation and maintenance have been proposed as more globally applicable. One such water reclamation system for both non-potable and potable reuse, is that approved by the State of North Carolina "for Type 2" reclaimed water (NCT2RW). NC Type 2 potable reuse systems consist of a sequence of tertiary treatment to produce well oxidized reclaimed water that is then then further treated by two steps of disinfection, typically UV radiation and chlorination. In this case study, the log10 microbial reduction performance of NCT2RW producing water reclamation facilities is evaluated. Based on the results presented here, NCT2RW consistently achieved high (6 for bacteria, 4 for virus and 4 for protozoan parasite surrogates) log10 reductions using the NC proposed treatment methods. Additionally, lower but significant log10 reduction performance was also documented for protozoan parasites and human enteric viruses. Copyright © 2018 Elsevier B.V. All rights reserved.
-
Evaluation of radio-frequency heating in controlling Salmonella enterica in raw shelled almonds.
Jeong, Seul-Gi; Baik, Oon-Doo; Kang, Dong-Hyun
2017-08-02
This study was conducted to investigate the efficacy of radio-frequency (RF) heating to reduce Salmonella enterica serovars Enteritidis, Typhimurium, and Senftenberg in raw shelled almonds compared to conventional convective heating, and the effect of RF heating on quality by measuring changes in the color and degree of lipid oxidation. Agar-grown cells of three pathogens were inoculated onto the surface or inside of raw shelled almonds using surface inoculation or the vacuum perfusion method, respectively, and subjected to RF or conventional heating. RF heating for 40s achieved 3.7-, 6.0-, and 5.6-log reductions in surface-inoculated S. Enteritidis, S. Typhimurium, and S. Senftenberg, respectively, whereas the reduction of these pathogens following convective heating for 600s was 1.7, 2.5, and 3.7 log, respectively. RF heating reduced internally inoculated pathogens to below the detection limit (0.7 logCFU/g) after 30s. However, conventional convective heating did not attain comparable reductions even at the end of treatment (600s). Color values, peroxide values, and acid values of RF-treated (40-s treatment) almonds were not significantly (P>0.05) different from those of nontreated samples. These results suggest that RF heating can be applied to control internalized pathogens as well as surface-adhering pathogens in raw almonds without affecting product quality. Copyright © 2017. Published by Elsevier B.V.
-
Hernández-Hernández, Elvia; Lira-Moreno, César Y; Guerrero-Legarreta, Isabel; Wild-Padua, Graciela; Di Pierro, Prospero; García-Almendárez, Blanca E; Regalado-González, Carlos
2017-06-01
Fresh meat is a highly perishable food. This work aimed to evaluate the influence of Mexican oregano (Lippia graveolens Kunth) incorporated into active coatings (ACs) spread on fresh pork meat as free (FEO), nanoemulsified (NEO), and microencapsulated (MEO) essential oil (EO), on its microbiological, physicochemical and sensory properties during 15 d at 4 ± 1 °C. Thymol and γ-terpinene were identified in the EO. In vitro effect of 2.85 mg EO/cm 2 was tested against Brochothrix thermosphacta, Micrococcus luteus, Lactobacillus plantarum, Pseudomonas fragi, and Salmonella Infantis. FEO antioxidant capacity (DPPH assay) was significantly higher than that of thymol, NEO and MEO (93.53%, 89.92%, 77.79%, and 78.50% inhibition, respectively), and similar to BHA (96.03%) and gallic acid (95.57%). FEO, NEO, and MEO ACs on meat caused growth inhibition of lactic acid bacteria (5 log population reduction) and Pseudomonas spp. (4 log reduction), whereas ≤1.5 log population reduction was observed for B. thermosphacta and Salmonella Infantis. Meat microbiota was more efficiently controlled by MEO than by FEO or NEO. ACs delayed lipid and oxymyoglobin oxidation of fresh pork meat. After 15 d of cold storage meat added with EO coatings was desirable for panelists, whereas untreated (UT) samples were undesirable. Active coatings are a significant alternative method for fresh meat preservation. © 2017 Institute of Food Technologists®.
-
Aghaie, A; Pourfatollah, A A; Bathaie, S Z; Moazzeni, S M; Khorsand Mohammad Pour, H; Sharifi, Z
2008-01-01
The safety of plasma derived medicinal products, such as immunoglobulin, depends on viral inactivation steps that are incorporated into the production process. Several attempts have been made to validate the effectiveness of these inactivation methods against a range of physio-chemically diverse viruses. Treatment with solvent/detergent (S/D) and pasteurization (P) has been continuously used in our IgG production and these methods were analysed in this study as models of viral inactivation. Bovine Viral Diarrhoea Virus (BVDV), Herpes Simplex Virus (HSV) and Vesicular Stomatitis Virus (VSV) were employed as models of HCV, HBV and HIV respectively. Polio and Reo viruses also were used as stable viruses to chemical substances. The infectivity of a range of viruses before and after treatment with two methods of viral inactivation was measured by end point titration and their effectiveness expressed as Logarithmic Reduction Factors (LRF). Solvent/detergent treatment reduced the amount of enveloped viruses by 5-6 logs. The reduction factor was between 5-6 logs for all viruses used in the pasteurization process. A final log reduction factor was obtained as the sum of the two individual methods. Both inactivation methods have advantages and disadvantages with respect to their ability to inactivate viruses. Thus,combination of two robust virus inactivation steps, solvent/detergent and pasteurization, increases the safety margin of immunoglobulin preparations.
-
Ultrasonic cleaning of conveyor belt materials using Listeria monocytogenes as a model organism.
Tolvanén, Riina; Lunden, Janne; Korkeala, Hannu; Wirtanen, Gun
2007-03-01
Persistent Listeria monocytogenes contamination of food industry equipment is a difficult problem to solve. Ultrasonic cleaning offers new possibilities for cleaning conveyors and other equipment that are not easy to clean. Ultrasonic cleaning was tested on three conveyor belt materials: polypropylene, acetal, and stainless steel (cold-rolled, AISI 304). Cleaning efficiency was tested at two temperatures (30 and 45 degrees C) and two cleaning times (30 and 60 s) with two cleaning detergents (KOH, and NaOH combined with KOH). Conveyor belt materials were soiled with milk-based soil and L. monocytogenes strains V1, V3, and B9, and then incubated for 72 h to attach bacteria to surfaces. Ultrasonic cleaning treatments reduced L. monocytogenes counts on stainless steel 4.61 to 5.90 log units; on acetal, 3.37 to 5.55 log units; and on polypropylene, 2.31 to 4.40 log units. The logarithmic reduction differences were statistically analyzed by analysis of variance using Statistical Package for the Social Sciences software. The logarithmic reduction was significantly greater in stainless steel than in plastic materials (P < 0.001 for polypropylene, P = 0.023 for acetal). Higher temperatures enhanced the cleaning efficiency in tested materials. No significant difference occurred between cleaning times. The logarithmic reduction was significantly higher (P = 0.013) in cleaning treatments with potassium hydroxide detergent. In this study, ultrasonic cleaning was efficient for cleaning conveyor belt materials.
-
Utilization and cost for animal logging operations
Suraj P. Shrestha; Bobby L. Lanford
2001-01-01
Forest harvesting with animals is a labor-intensive operation. Due to the development of efficient machines and high volume demands from the forest products industry, mechanization of logging developed very fast, leaving behind the traditional horse and mule logging. It is expensive to use machines on smaller woodlots, which require frequent moves if mechanically...
-
40 CFR 146.22 - Construction requirements.
Code of Federal Regulations, 2010 CFR
2010-07-01
... caliper logs before casing is installed; and (B) A cement bond, temperature, or density log after the...; and (C) A cement bond, temperature, or density log after the casing is set and cemented. (g) At a... drinking water. The casing and cement used in the construction of each newly drilled well shall be designed...
-
Robust Spatial Autoregressive Modeling for Hardwood Log Inspection
Dongping Zhu; A.A. Beex
1994-01-01
We explore the application of a stochastic texture modeling method toward a machine vision system for log inspection in the forest products industry. This machine vision system uses computerized tomography (CT) imaging to locate and identify internal defects in hardwood logs. The application of CT to such industrial vision problems requires efficient and robust image...
-
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Data logging. 90.412 Section 90.412....412 Data logging. (a) A computer or any other automatic data collection (ADC) device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection...
-
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Data logging. 89.409 Section 89.409... Data logging. (a) A computer or any other automatic data processing device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection records the...
-
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Data logging. 89.409 Section 89.409... Data logging. (a) A computer or any other automatic data processing device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection records the...
-
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Data logging. 90.412 Section 90.412....412 Data logging. (a) A computer or any other automatic data collection (ADC) device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection...
-
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Data logging. 89.409 Section 89.409... Data logging. (a) A computer or any other automatic data processing device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection records the...
-
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Data logging. 90.412 Section 90.412....412 Data logging. (a) A computer or any other automatic data collection (ADC) device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection...
-
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Data logging. 89.409 Section 89.409... Data logging. (a) A computer or any other automatic data processing device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection records the...
-
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Data logging. 90.412 Section 90.412....412 Data logging. (a) A computer or any other automatic data collection (ADC) device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection...
-
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Data logging. 89.409 Section 89.409... Data logging. (a) A computer or any other automatic data processing device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection records the...
-
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Data logging. 90.412 Section 90.412....412 Data logging. (a) A computer or any other automatic data collection (ADC) device(s) may be used as long as the system meets the requirements of this subpart. (b) Determine from the data collection...
-
Bonifácio, D; Martins, C; David, B; Lemos, C; Neves, M G P M S; Almeida, A; Pinto, D C G A; Faustino, M A F; Cunha, Â
2018-03-22
The aim of this work is to assess the potential of curcumin in the photosensitization of biofilms of Listeria. Biofilms of Listeria innocua, were irradiated with blue light in the presence of a curcumin-rich extract of Curcuma longa or commercial curcumin. Similar experiments were conducted with planktonic cells, for comparison. A reduction of 4·9 log in the concentration of viable biofilm cells was obtained with 3·7 mg l -1 of commercial curcumin. Planktonic cells were much more susceptible (6·1 log reduction). A tetracationic porphyrin, used as a reference photosensitizer (PS), caused a very modest inactivation of the biofilm (1·1 log) and complete inactivation of the planktonic form (>8 log). Curcumin is an effective PS for the photodynamic control of Listeria biofilms and the inactivation efficiency attained with this natural compound is higher than with the porphyrin. This result may point to a better performance of type I PSs against bacterial biofilms by circumventing the limitations to singlet-oxygen diffusion imposed by the extracellular matrix. Curcumin represents a promising alternative to the control of bacteria and bacterial biofilms in food products particularly in the case of meat products in which turmeric is used as spice. © 2018 The Society for Applied Microbiology.
-
Grasso, Elizabeth M; Uribe-Rendon, Roberto M; Lee, Ken
2011-01-01
During the past decade there were more than 50 reported outbreaks involving leafy green vegetables contaminated with foodborne pathogens. Leafy greens, including cabbage, are fresh foods rarely heated before consumption, which enables foodborne illness. The need for improved safety of fresh food drives the demand for nonthermal food processes to decrease the risk of pathogens while maintaining fresh quality. This study examines the efficacy of electron-beam (e-beam) irradiation in decreasing indigenous microflora on fresh-cut cabbage and determines the optimal dosage to pasteurize fresh-cut cabbage inoculated with Escherichia coli K-12. Fresh-cut cabbage (100 g) was inoculated with ∼8 log E. coli K-12 and e-beam irradiated at doses of 0, 1.0, 2.3, or 4.0 kGy. At 2.3 kGy there was <1.0 log indigenous microflora remaining, indicating greater than a 4.0-log reduction by e-beam. At a 4.0-kGy dose there was >7-log reduction of E. coli K-12 in the fresh-cut cabbage. The D(10)-value for E. coli K-12 in fresh-cut cabbage was 0.564 kGy. E-beam irradiation is thus a viable nonthermal treatment that extends the shelf life and increases the safety of fresh cabbage by reducing or eliminating indigenous microflora and unwanted pathogens.
-
Buckley, David; Dharmasena, Muthu; Fraser, Angela; Pettigrew, Charles; Anderson, Jeffery; Jiang, Xiuping
2018-06-15
Carpets and other soft surfaces have been associated with prolonged and reoccurring human norovirus (HuNoV) outbreaks. Environmental hygiene programs are important to prevent and control HuNoV outbreaks. Despite our knowledge of HuNoV transmission via soft surfaces, no commercially available disinfectants have been evaluated on carpets. Our aim was to adapt a current standardized method for virucidal testing by assessing two disinfection technologies, silver dihydrogen citrate (SDC) and steam vapor, against one HuNoV surrogate, feline calicivirus (FCV), on wool and nylon carpets. First, we evaluated the effect of both technologies on the appearance of carpet. Next, we evaluated the efficacy of SDC in suspension and the efficacy of SDC and steam vapor against FCV on a glass surface, each with and without serum. Lastly, we tested both technologies on two types of carpet, wool and nylon. Both carpets exhibited no obvious color changes; however, SDC treatments left a residue while steam vapor left minor abrasions to fibers. SDC in suspension and on glass reduced FCV by 4.65 log 10 and >4.66 log 10 PFU, respectively, but demonstrated reduced efficacy in the presence of serum. However, SDC was only efficacious against FCV on nylon (3.62-log 10 PFU reduction) and not wool (1.82-log 10 PFU reduction). Steam vapor reduced FCV by >4.93 log 10 PFU on glass in 10 s and >3.68 log 10 PFU on wool and nylon carpet carriers in 90 s. There was a limited reduction of FCV RNA under both treatments compared to that of infectivity assays, but RNA reductions were higher in samples that contained serum. IMPORTANCE Human noroviruses (HuNoV) account for ca. 20% of all diarrheal cases worldwide. Disease symptoms may include diarrhea and vomit, with both known to contribute to transmission. The prevention and control of HuNoV are difficult because they are environmentally resilient and resistant to many disinfectants. Several field studies have linked both hard and soft surfaces to HuNoV outbreaks. However, many disinfectants efficacious against HuNoV surrogates are recommended for hard surfaces, but no commercially available products have demonstrated efficacy against these surrogates on soft surfaces. Our research objectives were to evaluate liquid and steam-based technologies in suspension and on hard surface carriers in addition to adapting and testing a protocol for assessing the virucidal effects of disinfection technologies on carpet carriers. These results will inform both the government and industry regarding a standard method for evaluating the virucidal effects of disinfectants on carpet while demonstrating their efficacy relative to suspension and hard-surface tests. Copyright © 2018 American Society for Microbiology.
-
15. Photocopy of photograph (4 x 5 inch reduction of ...
15. Photocopy of photograph (4 x 5 inch reduction of 1939 3-1/4 x 5-1/2 inch print, photographer unknown; in Recreation files, Supervisor's Office, Mt. Baker-Snoqualmie National Forest) GENERAL VIEW, LOOKING SOUTHWEST, SHOWING INTERPRETIVE LOG AND PROTECTION ASSISTANT'S HOUSE IN BACKGROUND. - Glacier Ranger Station, Washington State Route 542, Glacier, Whatcom County, WA
-
Short-term effects of fuel reduction on pileated woodpeckers in northeastern Oregon—a pilot study.
Evelyn L. Bull; Abe A. Clark; Jay F. Shepherd
2005-01-01
To determine the short-term effects (1 to 3 years posttreatment) of fuel reduction on pileated woodpeckers (Dryocopus pileatus) in northeastern Oregon, we compared measures of abundance of logs, snags, stumps, and of woodpecker foraging in mixed-conifer stands that had undergone the following treatments: prescribed burning after mechanical fuel...
-
N. Sasaki; G.P. Asner; Yude Pan; W. Knorr; P.B. Durst; H.O. Ma; I. Abe; A.J. Lowe; L.P. Koh
2016-01-01
The REDD+ scheme of the United Nations Framework Conventionon Climate Change has provided opportunities to manage tropical forests for timber production and carbon emission reductions. To determine the appropriate loggingtechniques, we analyzed potential timber production and carbon emission reductions under two logging techniques over a 40-year period of selective...
-
Tsuji, Brian T; Harigaya, Yoriko; Lesse, Alan J; Forrest, Alan; Ngo, Dung
2013-01-01
AFN-1252, a potent enoyl-ACP reductase (FabI) inhibitor, is under development for the treatment of Staphylococcus aureus infections. The activity of AFN-1252 against two isolates of S. aureus, MSSA 26213 and MRSA S186, was studied in an in vitro pharmacodynamic model simulating AFN-1252 pharmacokinetics in man. Reductions in bacterial viable count over the first 6 hours were generally 1–2 logs and maximal reductions in viable count were generally achieved at fAUC/MIC ratios of 100–200. Maximum reductions in viable count against MSSA 29213 and MRSA S186 were approximately 4 logs, achieved by 450 mg q12h (fAUC/MIC = 1875) dosing at 28 hours. Staphylococcal resistance to AFN-1252 did not develop throughout the 48-hour experiments. As multidrug resistance continues to increase, these studies support the continued investigation of AFN-1252 as a targeted therapeutic for staphylococcal infections. PMID:23433442
-
Loraine, Gregory; Chahine, Georges; Hsiao, Chao-Tsung; Choi, Jin-Keun; Aley, Patrick
2012-05-01
Cavitating jet technologies (DynaJets®) were investigated as a means of disinfection of gram-negative Escherichia coli, Klebsiellapneumoniae, Pseudomonas syringae, and Pseudomonas aeruginosa, and gram-positive Bacillus subtilis. The hydrodynamic cavitating jets were found to be very effective in reducing the concentrations of all of these species. In general, the observed rates of disinfection of gram-negative species were higher than for gram-positive species. However, different gram-negative species also showed significant differences (P. syringae 6-log(10) reduction, P. aeruginosa 2-log(10) reduction) under the same conditions. Disinfection of E. coli repeatedly showed five orders of magnitude reduction in concentration within 45-60-min at low nozzle pressure (2.1 bar). Optimization of nozzle design and operating pressures increased disinfection rates per input energy by several orders of magnitude. The power efficiencies of the hydrodynamic cavitating jets were found to be 10-100 times greater than comparable ultrasonic systems. Copyright © 2011 Elsevier B.V. All rights reserved.
-
New Approach To Produce Water Free of Bacteria, Viruses, and Halogens in a Recyclable System▿
Ahmed, Abd El-Shafey I.; Cavalli, Gabriel; Bushell, Michael E.; Wardell, John N.; Pedley, Steve; Charles, Katarina; Hay, John N.
2011-01-01
The antimicrobial activity of a new cross-linked N-halamine polymer against bacteria and viruses was evaluated. The polymer achieved a 9-log10 reduction of bacteria (both Escherichia coli and Staphylococcus aureus) in 1.5 h and a 5-log10 reduction of bacteriophage PRD1 in 3 h. At the same time, the ability of the nonhalogenated polymer to trap halide ions was examined. The polymer was incorporated into a multifiltration system to study the ability to produce water free of bacteria, viruses, and halide ions. The antimicrobial activity, useful lifetime, halide ion level, and recycling possibilities of the system were quantified on a laboratory scale. A design for a large-scale multifiltration system based on this polymer is proposed. PMID:21115711
-
NASA Technical Reports Server (NTRS)
Havelund, Klaus; Smith, Margaret H.; Barringer, Howard; Groce, Alex
2012-01-01
LogScope is a software package for analyzing log files. The intended use is for offline post-processing of such logs, after the execution of the system under test. LogScope can, however, in principle, also be used to monitor systems online during their execution. Logs are checked against requirements formulated as monitors expressed in a rule-based specification language. This language has similarities to a state machine language, but is more expressive, for example, in its handling of data parameters. The specification language is user friendly, simple, and yet expressive enough for many practical scenarios. The LogScope software was initially developed to specifically assist in testing JPL s Mars Science Laboratory (MSL) flight software, but it is very generic in nature and can be applied to any application that produces some form of logging information (which almost any software does).
-
Mathieu, Didier
2017-09-01
Two new models are introduced to predict the solubility of chemicals in octanol (S oct ), taking advantage of the extensive character of log(S oct ) through a decomposition of molecules into so-called geometrical fragments (GF). They are extensively validated and their compliance with regulatory requirements is demonstrated. The first model requires just a molecular formula as input. Despite an extreme simplicity, it performs as well as an advanced random forest model involving 86 descriptors, with a root mean square error (RMSE) of 0.64 log units for an external test set of 100 molecules. For the second one, which requires the melting point T m as input, introducing GF descriptors reduces the RMSE from about 0.7 to <0.5 log units, a performance that could previously be obtained only through the use of Abraham descriptors. A script is provided for easy application of the models, taking into account the limits of their applicability domains. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
47 CFR 76.1704 - Proof-of-performance test data.
Code of Federal Regulations, 2011 CFR
2011-10-01
...-performance test data. (a) The proof of performance tests required by § 76.601 shall be maintained on file at... subscribers, subject to the requirements of § 76.601(d). Note to § 76.1704: If a signal leakage log is being... log must be retained for the period specified in § 76.601(d). ...
-
47 CFR 76.1704 - Proof-of-performance test data.
Code of Federal Regulations, 2010 CFR
2010-10-01
...-performance test data. (a) The proof of performance tests required by § 76.601 shall be maintained on file at... subscribers, subject to the requirements of § 76.601(d). Note to § 76.1704: If a signal leakage log is being... log must be retained for the period specified in § 76.601(d). ...
-
76 FR 13526 - Reducing Regulatory Burden; Retrospective Review Under Executive Order 13563
Federal Register 2010, 2011, 2012, 2013, 2014
2011-03-14
... participate using an existing social media account such as Facebook or Twitter. For further information, see... either SPAM/Inappropriate or Duplicate (log-in required); (6) Share ideas through a Twitter feed or on your Facebook page (log-in required for IdeaScale, as well as an active Facebook and/or Twitter account...
-
Gehr, Ronald; Wagner, Monika; Veerasubramanian, Priya; Payment, Pierre
2003-11-01
The City of Montreal Wastewater Treatment Plant uses enhanced physicochemical processes (ferric and/or alum coagulation) for suspended solids and phosphorus removal. The objective of this study was to assess the ability of peracetic acid (PAA), UV, or ozone to inactivate the indicator organisms fecal coliforms, Enterococci, MS-2 coliphage, or Clostridium perfringens in the effluent from this plant. PAA doses to reach the target fecal coliform level of 9000 CFU/100mL exceeded 6 mg/L; similar results were obtained for enterococci, and no inactivation of Clostridium perfringens was observed. However a 1-log reduction of MS-2 occurred at PAA doses of 1.5 mg/L and higher. It was expected that this effluent would have a high ozone demand, and would require relatively high UV fluences, because of relatively high effluent COD, iron and suspended solids concentrations, and low UV transmittance. This was confirmed herein. For UV, the inactivation curve for fecal coliforms showed the typical two-stage shape, with the target of 1000 CFU/100 mL (to account for photoreactivation) occurring in the asymptote zone at fluences >20 mJ/cm(2). In contrast, inactivation curves for MS-2 and Clostridium perfringens were linear. Clostridium perfringens was the most resistant organism. For ozone, inactivation was already observed before any residuals could be measured. The transferred ozone doses to reach target fecal coliform levels ( approximately 2-log reduction) were 30-50 mg/L. MS-2 was less resistant, but Clostridium perfringens was more resistant than fecal coliforms. The different behaviour of the four indicator organisms studied, depending on the disinfectant, suggests that a single indicator organism might not be appropriate. The required dose of any of the disinfectants is unlikely to be economically viable, and upstream changes to the plant will be needed.
-
Symonds, E M; Verbyla, M E; Lukasik, J O; Kafle, R C; Breitbart, M; Mihelcic, J R
2014-11-15
Wastewater treatment ponds (WTP) are one of the most widespread treatment technologies in the world; however, the mechanisms and extent of enteric virus removal in these systems are poorly understood. Two WTP systems in Bolivia, with similar overall hydraulic retention times but different first stages of treatment, were analyzed for enteric virus removal. One system consisted of a facultative pond followed by two maturation ponds (three-pond system) and the other consisted of an upflow anaerobic sludge blanket (UASB) reactor followed by two maturation (polishing) ponds (UASB-pond system). Quantitative polymerase chain reaction with reverse transcription (RT-qPCR) was used to measure concentrations of norovirus, rotavirus, and pepper mild mottle virus, while cell culture methods were used to measure concentrations of culturable enteroviruses (EV). Limited virus removal was observed with RT-qPCR in either system; however, the three-pond system removed culturable EV with greater efficiency than the UASB-pond system. The majority of viruses were not associated with particles and only a small proportion was associated with particles larger than 180 μm; thus, it is unlikely that sedimentation is a major mechanism of virus removal. High concentrations of viruses were associated with particles between 0.45 and 180 μm in the UASB reactor effluent, but not in the facultative pond effluent. The association of viruses with this size class of particles may explain why only minimal virus removal was observed in the UASB-pond system. Quantitative microbial risk assessment of the treated effluent for reuse for restricted irrigation indicated that the three-pond system effluent requires an additional 1- to 2-log10 reduction of viruses to achieve the WHO health target of <10(-4) disability-adjusted life years (DALYs) lost per person per year; however, the UASB-pond system effluent may require an additional 2.5- to 4.5-log10 reduction of viruses. Copyright © 2014 Elsevier Ltd. All rights reserved.
-
Analysis of Hospital Processes with Process Mining Techniques.
Orellana García, Arturo; Pérez Alfonso, Damián; Larrea Armenteros, Osvaldo Ulises
2015-01-01
Process mining allows for discovery, monitoring, and improving processes identified in information systems from their event logs. In hospital environments, process analysis has been a crucial factor for cost reduction, control and proper use of resources, better patient care, and achieving service excellence. This paper presents a new component for event logs generation in the Hospital Information System or HIS, developed at University of Informatics Sciences. The event logs obtained are used for analysis of hospital processes with process mining techniques. The proposed solution intends to achieve the generation of event logs in the system with high quality. The performed analyses allowed for redefining functions in the system and proposed proper flow of information. The study exposed the need to incorporate process mining techniques in hospital systems to analyze the processes execution. Moreover, we illustrate its application for making clinical and administrative decisions for the management of hospital activities.
-
Semi-inclusive wino and higgsino annihilation to LL'
Baumgart, Matthew; Vaidya, Varun
2016-03-31
Here, we systematically compute the annihilation rate for winos and higgsinos into the final state relevant for indirect detection experiments, γ + X. The radiative corrections to this process receive enhancement from the large Bloch-Nordsieck-Violating Sudakov logarithm, log(2Mmore » $${\\chi }$$/M W). We resum the double logs and include single logs to fixed order using a formalism that combines nonrelativistic and soft-collinear effective field theories. For the wino case, we update an earlier exclusion adapting results of the HESS experiment. At the thermal relic mass of 3 TeV, LL' corrections result in a ~30% reduction in rate relative to LL. But, single logs do not save the wino, and it is still excluded by an order of magnitude. Finally, experimental cuts produce an endpoint region which, our results show, significantly effects the higgsino rate at its thermal-relic mass near 1 TeV and is deserving of further study.« less
-
Beuchat, Larry R; Pettigrew, Charles A; Tremblay, Mario E; Roselle, Brian J; Scouten, Alan J
2004-08-01
Chlorine, ClO2, and a commercial raw fruit and vegetable sanitizer were evaluated for their effectiveness in killing vegetative cells and spores of Bacillus cereus and spores of Bacillus thuringiensis. The ultimate goal was to use one or both species as a potential surrogate(s) for Bacillus anthracis in studies that focus on determining the efficacy of sanitizers in killing the pathogen on food contact surfaces and foods. Treatment with alkaline (pH 10.5 to 11.0) ClO2 (200 microg/ml) produced by electrochemical technologies reduced populations of a five-strain mixture of vegetative cells and a five-strain mixture of spores of B. cereus by more than 5.4 and more than 6.4 log CFU/ml respectively, within 5 min. This finding compares with respective reductions of 4.5 and 1.8 log CFU/ml resulting from treatment with 200 microg/ml of chlorine. Treatment with a 1.5% acidified (pH 3.0) solution of Fit powder product was less effective, causing 2.5- and 0.4-log CFU/ml reductions in the number of B. cereus cells and spores, respectively. Treatment with alkaline ClO2 (85 microg/ml), acidified (pH 3.4) ClO2 (85 microg/ml), and a mixture of ClO2 (85 microg/ml) and Fit powder product (0.5%) (pH 3.5) caused reductions in vegetative cell/spore populations of more than 5.3/5.6, 5.3/5.7, and 5.3/6.0 log CFU/ml, respectively. Treatment of B. cereus and B. thuringiensis spores in a medium (3.4 mg/ml of organic and inorganic solids) in which cells had grown and produced spores with an equal volume of alkaline (pH 12.1) ClO2 (400 microg/ml) for 30 min reduced populations by 4.6 and 5.2 log CFU/ml, respectively, indicating high lethality in the presence of materials other than spores that would potentially react with and neutralize the sporicidal activity of ClO2.
-
Samelis, John; Sofos, John N.; Kendall, Patricia A.; Smith, Gary C.
2001-01-01
Depending on its composition and metabolic activity, the natural flora that may be established in a meat plant environment can affect the survival, growth, and acid tolerance response (ATR) of bacterial pathogens present in the same niche. To investigate this hypothesis, changes in populations and ATR of inoculated (105 CFU/ml) Listeria monocytogenes were evaluated at 35°C in water (10 or 85°C) or acidic (2% lactic or acetic acid) washings of beef with or without prior filter sterilization. The model experiments were performed at 35°C rather than lower (≤15°C) temperatures to maximize the response of inoculated L. monocytogenes in the washings with or without competitive flora. Acid solution washings were free (<1.0 log CFU/ml) of natural flora before inoculation (day 0), and no microbial growth occurred during storage (35°C, 8 days). Inoculated L. monocytogenes died off (negative enrichment) in acid washings within 24 h. In nonacid (water) washings, the pathogen increased (approximately 1.0 to 2.0 log CFU/ml), irrespective of natural flora, which, when present, predominated (>8.0 log CFU/ml) by day 1. The pH of inoculated water washings decreased or increased depending on absence or presence of natural flora, respectively. These microbial and pH changes modulated the ATR of L. monocytogenes at 35°C. In filter-sterilized water washings, inoculated L. monocytogenes increased its ATR by at least 1.0 log CFU/ml from days 1 to 8, while in unfiltered water washings the pathogen was acid tolerant at day 1 (0.3 to 1.4 log CFU/ml reduction) and became acid sensitive (3.0 to >5.0 log CFU/ml reduction) at day 8. These results suggest that the predominant gram-negative flora of an aerobic fresh meat plant environment may sensitize bacterial pathogens to acid. PMID:11375145
-
Bruce, Alison; Fairley, Lesley; Chambers, Bette; Wright, John; Sheldon, Trevor A
2016-02-16
To estimate the prevalence of poor vision in children aged 4-5 years and determine the impact of visual acuity on literacy. Cross-sectional study linking clinical, epidemiological and education data. Schools located in the city of Bradford, UK. Prevalence was determined for 11,186 children participating in the Bradford school vision screening programme. Data linkage was undertaken for 5836 Born in Bradford (BiB) birth cohort study children participating both in the Bradford vision screening programme and the BiB Starting Schools Programme. 2025 children had complete data and were included in the multivariable analyses. Visual acuity was measured using a logMAR Crowded Test (higher scores=poorer visual acuity). Literacy measured by Woodcock Reading Mastery Tests-Revised (WRMT-R) subtest: letter identification (standardised). The mean (SD) presenting visual acuity was 0.14 (0.09) logMAR (range 0.0-1.0). 9% of children had a presenting visual acuity worse than 0.2logMAR (failed vision screening), 4% worse than 0.3logMAR (poor visual acuity) and 2% worse than 0.4logMAR (visually impaired). Unadjusted analysis showed that the literacy score was associated with presenting visual acuity, reducing by 2.4 points for every 1 line (0.10logMAR) reduction in vision (95% CI -3.0 to -1.9). The association of presenting visual acuity with the literacy score remained significant after adjustment for demographic and socioeconomic factors reducing by 1.7 points (95% CI -2.2 to -1.1) for every 1 line reduction in vision. Prevalence of decreased visual acuity was high compared with other population-based studies. Decreased visual acuity at school entry is associated with reduced literacy. This may have important implications for the children's future educational, health and social outcomes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
-
40 CFR 146.12 - Construction requirements.
Code of Federal Regulations, 2013 CFR
2013-07-01
... potential, porosity, and gamma ray logs before the casing is installed; (B) Fracture finder logs; and (C) A... wells: (1) Fluid pressure; (2) Temperature; (3) Fracture pressure; (4) Other physical and chemical...
-
40 CFR 146.12 - Construction requirements.
Code of Federal Regulations, 2012 CFR
2012-07-01
... potential, porosity, and gamma ray logs before the casing is installed; (B) Fracture finder logs; and (C) A... wells: (1) Fluid pressure; (2) Temperature; (3) Fracture pressure; (4) Other physical and chemical...
-
40 CFR 146.12 - Construction requirements.
Code of Federal Regulations, 2014 CFR
2014-07-01
... potential, porosity, and gamma ray logs before the casing is installed; (B) Fracture finder logs; and (C) A... wells: (1) Fluid pressure; (2) Temperature; (3) Fracture pressure; (4) Other physical and chemical...
-
Collazo, Cyrelys; Abadías, Maribel; Colás-Medà, Pilar; Iglesias, María Belén; Granado-Serrano, Ana Belén; Serrano, José; Viñas, Inmaculada
2017-12-04
To further gain insight into the mechanism by which the biopreservative bacterium Pseudomonas graminis CPA-7 develops its antimicrobial activity, we have examined the effect that the prior interaction stablished by this bacterium and two foodborne pathogens on fresh-cut pear, has on their capacity to colonize human epithelial cells (Caco-2 cell line) which is crucial for establishing infection. CPA-7 inhibited the growth of L. monocytogenes and S. enterica subsp. enterica ser. Enteritidis by 5.5 and 3.1 log 10 , respectively, after 7d of interaction at 10°C. Furthermore, CPA-7 attenuated the adherence of S. enterica to Caco-2 cells by 0.8 log 10 regardless of the pre-adaptation on the fruit. Conversely, the adhesiveness of L. monocytogenes was not influenced by the interaction with the antagonist but it was reduced by 0.5 log 10 after incubation on the food matrix. Pathogen-antagonist-food matrix interaction was associated to a significant reduction of the relative invasiveness of both pathogens, by 1.3 log 10 in the case of L. monocytogenes and to an undetectable level (below 5CFU/g fruit) for S. enterica. CPA-7 can adhere to and internalize into intestinal epithelium which enables it for competition. Its adherence positively correlates to the multiplicity of infection (MOI) with respect to Caco-2 cells, increasing by 0.6 log 10 in an MOI range of 0.1:1 to 100:1. For the same levels of inoculum, internalized cells could only be detected after 7d of pre-adaptation in the fruit (pH4.5-5.0). However, the combination of gastrointestinal digestion and habituation on the fruit resulted in a significant reduction of CPA-7 populations (by 2 log 10 more after 7d of incubation than on inoculation day) as well as in the decrease of its adhesiveness (by 0.8 log 10 ) and invasiveness (to undetectable levels). Copyright © 2017 Elsevier B.V. All rights reserved.
-
Jelden, Katelyn C; Gibbs, Shawn G; Smith, Philip W; Hewlett, Angela L; Iwen, Peter C; Schmid, Kendra K; Lowe, John J
2017-06-01
An ultraviolet germicidal irradiation (UVGI) generator (the TORCH, ClorDiSys Solutions, Inc.) was used to compare the disinfection of surface coupons (plastic from a bedrail, stainless steel, and chrome-plated light switch cover) in a hospital room with walls coated with ultraviolet (UV)-reflective paint (Lumacept) or standard paint. Each surface coupon was inoculated with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus faecalis (VRE), placed at 6 different sites within a hospital room coated with UV-reflective paint or standard paint, and treated by 10 min UVC exposure (UVC dose of 0-688 mJ/cm 2 between sites with standard paint and 0-553 mJ/cm 2 with UV-reflective paint) in 8 total trials. Aggregated MRSA concentrations on plastic bedrail surface coupons were reduced on average by 3.0 log 10 (1.8 log 10 Geometric Standard Deviation [GSD]) with standard paint and 4.3 log 10 (1.3 log 10 GSD) with UV-reflective paint (p = 0.0005) with no significant reduction differences between paints on stainless steel and chrome. Average VRE concentrations were reduced by ≥4.9 log 10 (<1.2 log 10 GSD) on all surface types with UV-reflective paint and ≤4.1 log 10 (<1.7 log 10 GSD) with standard paint (p < 0.05). At 5 aggregated sites directly exposed to UVC light, MRSA concentrations on average were reduced by 5.2 log 10 (1.4 log 10 GSD) with standard paint and 5.1 log 10 (1.2 log 10 GSD) with UV-reflective paint (p = 0.017) and VRE by 4.4 log 10 (1.4 log 10 GSD) with standard paint and 5.3 log 10 (1.1 log 10 GSD) with UV-reflective paint (p < 0.0001). At one indirectly exposed site on the opposite side of the hospital bed from the UVGI generator, MRSA concentrations on average were reduced by 1.3 log 10 (1.7 log 10 GSD) with standard paint and 4.7 log 10 (1.3 log 10 GSD) with UV-reflective paint (p < 0.0001) and VRE by 1.2 log 10 (1.5 log 10 GSD) with standard paint and 4.6 log 10 (1.1 log 10 GSD) with UV-reflective paint (p < 0.0001). Coating hospital room walls with UV-reflective paint enhanced UVGI disinfection of nosocomial bacteria on various surfaces compared to standard paint, particularly at a surface placement site indirectly exposed to UVC light.
-
... medication. Protein Synthesis Inhibitor Therapy. Omacetaxine (Synribo®) a non-TKI, chemotherapy drug, is approved for chronic and ... as BCR-ABL 10%. This reduction is approximately equivalent to a major cytogenetic response. {{ A 2-log ...
-
Reiss, Rebecca A; Guerra, Peter; Makhnin, Oleg
2016-01-01
Chlorinated solvent contamination of potable water supplies is a serious problem worldwide. Biostimulation protocols can successfully remediate chlorinated solvent contamination through enhanced reductive dechlorination pathways, however the process is poorly understood and sometimes stalls creating a more serious problem. Whole metagenome techniques have the potential to reveal details of microbial community changes induced by biostimulation. Here we compare the metagenome of a tetrachloroethene contaminated Environmental Protection Agency Superfund Site before and after the application of biostimulation protocols. Environmental DNA was extracted from uncultured microbes that were harvested by on-site filtration of groundwater one month prior to and five months after the injection of emulsified vegetable oil, nutrients, and hydrogen gas bioamendments. Pair-end libraries were prepared for high-throughput DNA sequencing and 90 basepairs from both ends of randomly fragmented 400 basepair DNA fragments were sequenced. Over 31 millions reads were annotated with Metagenome Rapid Annotation using Subsystem Technology representing 32 prokaryotic phyla, 869 genera, and 3,181 species. A 3.6 log 2 fold increase in biomass as measured by DNA yield per mL water was measured, but there was a 9% decrease in the number of genera detected post-remediation. We apply Bayesian statistical methods to assign false discovery rates to fold-change abundance data and use Zipf's power law to filter genera with low read counts. Plotting the log-rank against the log-fold-change facilitates the visualization of the changes in the community in response to the enhanced reductive dechlorination protocol. Members of the Archaea domain increased 4.7 log 2 fold, dominated by methanogens. Prior to remediation, classes Alphaproteobacteria and Betaproteobacteria dominated the community but exhibit significant decreases five months after biostimulation. Geobacter and Sulfurospirillum replace " Sideroxydans " and Burkholderia as the most abundant genera. As a result of biostimulation, Deltaproteobacteria and Epsilonproteobacteria capable of dehalogenation, iron and sulfate reduction, and sulfur oxidation increase. Matches to thermophilic, haloalkane respiring archaea is evidence for additional species involved in biodegradation of chlorinated solvents. Additionally, potentially pathogenic bacteria increase, indicating that there may be unintended consequences of bioremediation.
-
Tornevi, Andreas; Simonsson, Magnus; Forsberg, Bertil; Säve-Söderbergh, Melle; Toljander, Jonas
2016-10-01
Outbreaks of acute gastrointestinal illnesses (AGI) have been linked to insufficient drinking water treatment on numerous occasions in the industrialized world, but it is largely unknown to what extent public drinking water influences the endemic level of AGI. This paper aimed to examine endemic AGI and the relationship with pathogen elimination efficacy in public drinking water treatment processes. For this reason, time series data of all telephone calls to the Swedish National Healthcare Guide between November 2007 and February 2014 from twenty Swedish cities were obtained. Calls concerning vomiting, diarrhea or abdominal pain (AGI calls) were separated from other concerns (non-AGI calls). Information on which type of microbial barriers each drinking water treatment plant in these cities have been used were obtained, together with the barriers' theoretical pathogen log reduction efficacy. The total log reduction in the drinking water plants varied between 0.0 and 6.1 units for viruses, 0.0-14.6 units for bacteria and 0.0-7.3 units regarding protozoans. To achieve one general efficacy parameter for each plant, a weighted mean value of the log reductions (WLR) was calculated, with the weights based on how commonly these pathogen groups cause AGI. The WLR in the plants varied between 0.0 and 6.4 units. The effect of different pathogen elimination efficacy on levels of AGI calls relative non-AGI calls was evaluated in regression models, controlling for long term trends, population size, age distribution, and climatological area. Populations receiving drinking water produced with higher total log reduction was associated with a lower relative number of AGI calls. In overall, AGI calls decreased by 4% (OR = 0.96, CI: 0.96-0.97) for each unit increase in the WLR. The findings apply to both groundwater and surface water study sites, but are particularly evident among surface water sites during seasons when viruses are the main cause of AGI. This study proposes that the endemic level of gastroenteritis can indeed be reduced with more advanced treatment processes at many municipal drinking water treatment plants. Copyright © 2016 Elsevier Ltd. All rights reserved.
-
Efficacy of sanitizers in reducing Salmonella on pecan nutmeats during cracking and shelling.
Beuchat, Larry R; Mann, David A; Alali, Walid Q
2013-05-01
Studies were done to evaluate the efficacy of chlorine (200 to 1,000 μg/ml), lactic acid (0.5 to 2%), levulinic acid (0.5 to 2%), sodium dodecyl sulfate (SDS, 0.05%), lactic acid plus SDS, levulinic acid plus SDS, and a mixed peroxyacid sanitizer (Tsunami 200, 40 and 80 μg/ml) in killing Salmonella on or in immersion- and on surface-inoculated pecan nutmeats (U.S. Department of Agriculture medium pieces and mammoth halves). The addition of SDS to treatment solutions containing lactic acid or levulinic acid resulted in generally higher reductions of Salmonella, but differences in these reductions were not always significant. Lactic and levulinic acids (2%) containing SDS (0.05%) were equivalent in killing Salmonella on immersion-inoculated nutmeats. Tsunami 200 (40 μg/ml) was less lethal or equivalent to 1 or 2% lactic and levulinic acids, with or without 0.05% SDS. Reductions did not exceed 1.1 log CFU/g of immersion-inoculated pieces and halves, regardless of sanitizer concentration or treatment time (up to 20 min). Reductions on surface-inoculated pieces and halves were 0.7 to 2.6 log CFU/g and 1.2 to 3.0 log CFU/g, respectively. Treatment with 2% lactic acid plus SDS (0.05%) and Tsunami (80 μg/ml) was most effective in killing Salmonella on surface-inoculated pieces; treatment of halves with chlorine (1,000 μg/ml) or lactic acid (1 or 2%), with or without SDS, was most efficacious. Exposure of immersion-inoculated pecan pieces to chlorine (200 μg/ml), lactic acid (2%) and levulinic acid (2%) with or without SDS, and Tsunami (80 μg/ml) during intermittent vacuum (18 ± 2 mbar) and ambient atmospheric pressure treatments for up to 20 min reduced Salmonella by only 0.1 to 1.0 log CFU/g. These studies emphasize the importance of preventing contamination of pecan nutmeats with Salmonella. Once nuts are contaminated, the lethality of sanitizers tested in this study is minimal.
-
Assessment of the efficacy of the first water system for emergency hospital use.
Long, Sharon C; Olstadt, Jeremy
2011-03-01
The First Water Responder B package water treatment device was evaluated for its ability to reduce the levels of spiked indicators and pathogens (Escherichia coli, MS2 coliphage, murine adenovirus, and Cryptosporidium oocysts) in a surface water to partially evaluate its appropriateness to be used to provide safe drinking water to hospitals during emergency situations. Lake water was collected in 50-L carboys and spiked with selected indicators and pathogens (E coli, MS2 coliphage, murine adenovirus, and Cryptosporidium oocysts) at 2 different spike levels (low and high). This water was treated using the First Water Responder B, and the microorganisms were enumerated before and after treatment using US Environmental Protection Agency and Standard Methods. Microbial removal efficiencies were compared with Environmental Protection Agency guidelines. E coli spikes ranged from 2.9 to 1059 colony-forming units (CFU)/100 mL with removals to below detection limits (1 CFU/100 mL) to 2.8 CFU/100 mL or 0.98 to 3.5 log(10) reductions. MS2 coliphage spikes ranged from 3 plaque-forming units (PFU) to 837 PFU/100 mL with removals to below detection limits (1 PFU/100 mL) to 11.7 PFU/100 mL or 0.65 to 1.9 log(10) reductions. Murine adenovirus spikes ranged from 203 to 8410 most probable number (MPN) of infectious units/100 mL with removals to below detection limits (23 MPN infectious units/100 mL) to 1370 MPN infectious units/100 mL or 0.79 to >1.2 log(10) reductions. Cryptosporidium parvum oocyst spikes ranged from 52 to 853 oocysts per liter with removals to below detection limits (<1 oocyst per liter) to 0.3 oocysts per liter or >2.2 to 3.4 log(10) reductions. Although the First Water system could remove a significant portion of the spiked organisms, it is recommended that this point-of-use system be coupled with chemical disinfection in a multiple-barrier approach to provide water of the highest reasonably achievable quality for hospital use in emergency situations. ©2011 American Medical Association. All rights reserved.
-
Haughton, P N; Lyng, J G; Cronin, D A; Morgan, D J; Fanning, S; Whyte, P
2011-04-01
UV light was investigated for the decontamination of raw chicken, associated packaging, and contact surfaces. The UV susceptibilities of a number of Campylobacter isolates (seven Campylobacter jejuni isolates and three Campylobacter coli isolates), Escherichia coli ATCC 25922, and Salmonella enterica serovar Enteritidis ATCC 10376 in liquid media were also investigated. From an initial level of 7 log CFU/ml, no viable Campylobacter cells were detected following exposure to the most intense UV dose (0.192 J/cm(2)) in liquid media (skim milk subjected to ultrahigh-temperature treatment and diluted 1:4 with maximum recovery diluent). Maximum reductions of 4.8 and 6.2 log CFU/ml were achieved for E. coli and serovar Enteritidis, respectively, in liquid media. Considerable differences in susceptibilities were found between the Campylobacter isolates examined, with variations of up to 4 log CFU/ml being observed. UV treatment of raw chicken fillet (0.192 J/cm(2)) reduced C. jejuni, E. coli, serovar Enteritidis, total viable counts, and Enterobacteriaceae by 0.76, 0.98, 1.34, 1.76, and 1.29 log CFU/g, respectively. Following UV treatment of packaging and surface materials, reductions of up to 3.97, 4.50, and 4.20 log CFU/cm(2) were obtained for C. jejuni, E. coli, and serovar Enteritidis, respectively (P < 0.05). Overall, the color of UV-treated chicken was not significantly affected (P ≥ 0.05). The findings of this study indicate that Campylobacter is susceptible to UV technology and that differences in sensitivities exist between investigated isolates. Overall, UV could be used for improving the microbiological quality of raw chicken and for decontaminating associated packaging and surface materials.
-
Kistemann, Thomas; Rind, Esther; Rechenburg, Andrea; Koch, Christoph; Classen, Thomas; Herbst, Susanne; Wienand, Ina; Exner, Martin
2008-10-01
Six sewage treatment plants (STP) were investigated over a 12-month period in order to measure the microbiological load of untreated municipal wastewater and to evaluate the removal efficiencies of different treatment systems. The STP investigated can be classified into three categories: bigger plants with tertiary treatment, smaller plants with enhanced secondary treatment, and very small compact facilities. The plants studied had a considerable quantitative impact on the hydrology of the catchment area; consequently, it was anticipated that the microbiological load of the effluent would also be significant. Eighty samples were taken from the influent and effluent of the STP, regardless of weather conditions, and several bacterial and two parasitological parameters were analysed. The average microbiological reduction of each STP was dependent on its capacity and treatment procedures and varied between 1.9 and 3.5log10. Small compact facilities had a significantly lower removal efficiency (2.0+/-1log10) and discharged treated wastewater with a poorer microbiological quality compared to larger plants with tertiary treatment or with enhanced secondary treatment (2.8log10). Final sand filtration and extensive intermediate settling considerably improved the overall microbiological removal efficiency. During the study period, the microbiological water quality of the receiving water course was not significantly impaired by the discharge of any of the investigated plants; however, the compact facilities showed critical treatment deficiencies. In particular, the reduction of Giardia cysts was insufficient (<1.5log10) compared to that of the bigger plants (>3.0log10). In order to quantify the overall impact of microbiological loads on the receiving watercourse in this catchment area, it is also necessary to assess the pollution from combined sewer overflow basins and diffuse pollution. This will be considered in subsequent studies.
-
NASA Astrophysics Data System (ADS)
Wenger, Amelia S.; Atkinson, Scott; Santini, Talitha; Falinski, Kim; Hutley, Nicholas; Albert, Simon; Horning, Ned; Watson, James E. M.; Mumby, Peter J.; Jupiter, Stacy D.
2018-04-01
Increasing development in tropical regions provides new economic opportunities that can improve livelihoods, but it threatens the functional integrity and ecosystem services provided by terrestrial and aquatic ecosystems when conducted unsustainably. Given the small size of many islands, communities may have limited opportunities to replace loss and damage to the natural resources upon which they depend for ecosystem service provisioning, thus heightening the need for proactive, integrated management. This study quantifies the effectiveness of management strategies, stipulated in logging codes-of-practice, at minimizing soil erosion and sediment runoff as clearing extent increases, using Kolombangara Island, Solomon Islands as a case study. Further, we examine the ability of erosion reduction strategies to maintain sustainable soil erosion rates and reduce potential downstream impacts to drinking water and environmental water quality. We found that increasing land clearing—even with best management strategies in place—led to unsustainable levels of soil erosion and significant impacts to downstream water quality, compromising the integrity of the land for future agricultural uses, consistent access to clean drinking water, and important downstream ecosystems. Our results demonstrate that in order to facilitate sustainable development, logging codes of practice must explicitly link their soil erosion reduction strategies to soil erosion and downstream water quality thresholds, otherwise they will be ineffective at minimizing the impacts of logging activities. The approach taken here to explicitly examine soil erosion rates and downstream water quality in relation to best management practices and increasing land clearing should be applied more broadly across a range of ecosystems to inform decision-making about the socioeconomic and environmental trade-offs associated with logging, and other types of land use change.
-
NASA Astrophysics Data System (ADS)
Kussovski, V.; Mantareva, V.; Angelov, I.; Avramov, L.; Popova, E.; Dimitrov, S.
2012-06-01
The Gram-negative, oral bacterium Aggregatibacter actinomycetemcomitans has been implicated as the causative agent of several forms of periodontal disease in humans. The new periodontal disease treatments are emergence in order to prevent infection progression. Antimicrobial photodynamic therapy (a-PDT) can be a useful tool for this purpose. It involves the use of light of specific wavelength to activate a nontoxic photosensitizing agent in the presence of oxygen for eradication of target cells, and appears effective in photoinactivation of microorganisms. The phthalocyanine metal complexes of Pd(II)- (PdPcC) and Al(III)- (AlPc1) were evaluated as photodynamic sensitizers towards a dental pathogen A. actinomycetemcomitans in comparison to the known methylpyridyloxy-substituted Zn(II) phthalocyanine (ZnPcMe). The planktonic and biofilm-cultivated species of A. actinomycetemcomitans were treated. The photophysical results showed intensive and far-red absorbance with high tendency of aggregation for Pd(II)-phthalocyanine. The dark toxicities of both photosensitizers were negligible at concentrations used (< 0.5 log decrease of viable cells). The photodynamic response for planktonic cultured bacteria was full photoinactivation after a-PDT with ZnPcMe. In case of the newly studied complexes, the effect was lower for PdPcC (4 log) as well as for AlPc1 (1.5-2 log). As it is known the bacterial biofilms were more resistant to a-PDT, which was confirmed for A. actinomycetemcomitans biofilms with 3 log reductions of viable cells after treatment with ZnPcMe and approximately 1 log reduction of biofilms after PdPcC and AlPc1. The initial results suggest that a-PDT can be useful for effective inactivation of dental pathogen A. actinomycetemcomitans.
-
Zollinger, Lilly; Schnyder, Simone; Nietzsche, Sandor; Sculean, Anton; Eick, Sigrun
2015-04-01
The antimicrobial activity of taurolidine was compared with minocycline against microbial species associated with periodontitis (four single strains and a 12-species mixture). Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs), killing as well as activities on established and forming single-species biofilms and a 12-species biofilm were determined. The MICs of taurolidine against single species were always 0.31 mg/ml, the MBCs were 0.64 mg/ml. The used mixed microbiota was less sensitive to taurolidine, MIC and the MBC was 2.5 mg/ml. The strains and the mixture were completely killed by 2.5 mg/ml taurolidine, whereas 256 μg/ml minocycline reduced the bacterial counts of the mixture by 5 log10 colony forming units (cfu). Coating the surface with 10 mg/ml taurolidine or 256 μg/ml minocycline prevented completely biofilm formation of Porphyromonas gingivalis ATCC 33277 but not of Aggregatibacter actinomycetemcomitans Y4 and the mixture. On 4.5 d old biofilms, taurolidine acted concentration dependent with a reduction by 5 log10 cfu (P. gingivalis ATCC 33277) and 7 log10 cfu (A. actinomycetemcomitans Y4) when applying 10 mg/ml. Minocycline decreased the cfu counts by 1-2 log10 cfu independent of the used concentration. The reduction of the cfu counts in the 4.5 d old multi-species biofilms was about 3 log10 cfu after application of any minocycline concentration and after using 10 mg/ml taurolidine. Taurolidine is active against species associated with periodontitis, even within biofilms. Nevertheless a complete elimination of complex biofilms by taurolidine seems to be impossible and underlines the importance of a mechanical removal of biofilms prior to application of taurolidine. Copyright © 2014 Elsevier Ltd. All rights reserved.
-
Dynamics of Tree Species Diversity in Unlogged and Selectively Logged Malaysian Forests.
Shima, Ken; Yamada, Toshihiro; Okuda, Toshinori; Fletcher, Christine; Kassim, Abdul Rahman
2018-01-18
Selective logging that is commonly conducted in tropical forests may change tree species diversity. In rarely disturbed tropical forests, locally rare species exhibit higher survival rates. If this non-random process occurs in a logged forest, the forest will rapidly recover its tree species diversity. Here we determined whether a forest in the Pasoh Forest Reserve, Malaysia, which was selectively logged 40 years ago, recovered its original species diversity (species richness and composition). To explore this, we compared the dynamics of secies diversity between unlogged forest plot (18.6 ha) and logged forest plot (5.4 ha). We found that 40 years are not sufficient to recover species diversity after logging. Unlike unlogged forests, tree deaths and recruitments did not contribute to increased diversity in the selectively logged forests. Our results predict that selectively logged forests require a longer time at least than our observing period (40 years) to regain their diversity.
-
Chloroxyanion residue quantification in cantaloupes treated with chlorine dioxide gas
USDA-ARS?s Scientific Manuscript database
Previous studies show that treatment of cantaloupes with chlorine dioxide (ClO2) gas at 5 mg/L for 10 minutes, results in a significant reduction (p<0.05) in initial microflora, an increase in shelf life without any alteration in color, and a 4.6 and 4.3 log reduction of E. coli O157:H7 and L. monoc...
-
Spacecraft Sterilization Using Non-Equilibrium Atmospheric Pressure Plasma
NASA Technical Reports Server (NTRS)
Cooper, Moogega; Vaze, Nachiket; Anderson, Shawn; Fridman, Gregory; Vasilets, Victor N.; Gutsol, Alexander; Tsapin, Alexander; Fridman, Alexander
2007-01-01
As a solution to chemically and thermally destructive sterilization methods currently used for spacecraft, non-equilibrium atmospheric pressure plasmas are used to treat surfaces inoculated with Bacillus subtilis and Deinococcus radiodurans. Evidence of significant morphological changes and reduction in viability due to plasma exposure will be presented, including a 4-log reduction of B. subtilis after 2 minutes of dielectric barrier discharge treatment.
-
A source strength model for prescribed fires in coniferous logging slash.
D.V. Sandberg; Janice Peterson
1984-01-01
Emission reduction has become an essential part of the effort to reduce air pollution from forest slash burning. The State of Washington has set a goal of reducing emissions by 35 percent by 1990, leaving the choice of emission reduction techniques to forest managers. Several thousand harvested areas are burned each year in the Northwest, encompassing a wide variety...
-
Marois-Fiset, Jean-Thomas; Carabin, Anne; Lavoie, Audrey
2013-01-01
The effects of temperature and pH on the water treatment performance of a point-of-use (POU) coagulant/disinfectant product were evaluated. Cold temperatures (∼5°C) reduced the bactericidal efficiency of the product with regard to Escherichia coli and total coliform log10 reductions. PMID:23335762
-
Vilela, Simone Furgeri Godinho; Junqueira, Juliana Campos; Barbosa, Junia Oliveira; Majewski, Marta; Munin, Egberto; Jorge, Antonio Olavo Cardoso
2012-06-01
The organization of biofilms in the oral cavity gives them added resistance to antimicrobial agents. The action of phenothiazinic photosensitizers on oral biofilms has already been reported. However, the action of the malachite green photosensitizer upon biofilm-organized microorganisms has not been described. The objective of the present work was to compare the action of malachite green with the phenothiazinic photosensitizers (methylene blue and toluidine blue) on Staphylococcus aureus and Escherichia coli biofilms. The biofilms were grown on sample pieces of acrylic resin and subjected to photodynamic therapy using a 660-nm diode laser and photosensitizer concentrations ranging from 37.5 to 3000 μM. After photodynamic therapy, cells from the biofilms were dispersed in a homogenizer and cultured in Brain Heart Infusion broth for quantification of colony-forming units per experimental protocol. For each tested microorganism, two control groups were maintained: one exposed to the laser radiation without the photosensitizer (L+PS-) and other treated with the photosensitizer without exposure to the red laser light (L-PS+). The results were subjected to descriptive statistical analysis. The best results for S. aureus and E. coli biofilms were obtained with photosensitizer concentrations of approximately 300 μM methylene blue, with microbial reductions of 0.8-1.0 log(10); 150 μM toluidine blue, with microbial reductions of 0.9-1.0 log(10); and 3000 μM malachite green, with microbial reductions of 1.6-4.0 log(10). Greater microbial reduction was achieved with the malachite green photosensitizer when used at higher concentrations than those employed for the phenothiazinic dyes. Copyright © 2011 Elsevier Ltd. All rights reserved.
-
Virucidal Influence of Ionic Liquids on Phages P100 and MS2
Fister, Susanne; Mester, Patrick; Sommer, Julia; Witte, Anna K.; Kalb, Roland; Wagner, Martin; Rossmanith, Peter
2017-01-01
An increasing number of publications describe the potential of ionic liquids (ILs) as novel antimicrobials, antibacterial coatings and even as active pharmaceutical ingredients. Nevertheless, a major research area, notably their impact on viruses, has so far been neglected. Consequently the aim of this study was to examine the effects of ILs on the infectivity of viruses. A systematic analysis to investigate the effects of defined structural elements of ILs on virus activity was performed using 55 ILs. All structure activity relationships (SARs) were tested on the human norovirus surrogate phage MS2 and phage P100 representing non-enveloped DNA viruses. Results demonstrate that IL SAR conclusions, established for prokaryotes and eukaryotes, are not readily applicable to the examined phages. A virus-type-dependent IL influence was also apparent. Overall, four ILs, covering different structural elements, were found to reduce phage P100 infectivity by ≥4 log10 units, indicating a virucidal effect, whereas the highest reduction for phage MS2 was about 3 log10 units. Results indicate that future applications of ILs as virucidal agents will require development of novel SARs and the obtained results serve as a good starting point for future studies. PMID:28883814
-
Himathongkham, S; Riemann, H; Bahari, S; Nuanualsuwan, S; Kass, P; Cliver, D O
2000-01-01
Exponential inactivation was observed for Salmonella typhimurium and Escherichia coli O157:H7 in poultry manure with decimal reduction times ranging from half a day at 37 C to 1-2 wk at 4 C. There was no material difference in inactivation rates between S. typhimurium and E. coli O157:H7. Inactivation was slower in slurries made by mixing two parts of water with one part of manure; decimal reduction times (time required for 90% destruction) ranged from 1-2 days at 37 C to 6-22 wk at 4 C. Escherichia coli O157:H7 consistently exhibited slightly slower inactivation than S. typhimurium. Log decimal reduction time for both strains was a linear function of storage temperature for manure and slurries. Chemical analysis indicated that accumulation of free ammonia in poultry manure was an important factor in inactivation of the pathogens. This finding was experimentally confirmed for S. typhimurium by adding ammonia directly to peptone water or to bovine manure, which was naturally low in ammonia, and adjusting pH to achieve predetermined levels of free ammonia.
-
Less and less-influence of volume on hand coverage and bactericidal efficacy in hand disinfection.
Kampf, Günter; Ruselack, Sigunde; Eggerstedt, Sven; Nowak, Nicolas; Bashir, Muhammad
2013-10-10
Some manufacturers recommend using 1.1 mL per application of alcohol-based handrubs for effective hand disinfection. However, whether this volume is sufficient to cover both hands, as recommended by the World Health Organization, and fulfills current efficacy standards is unknown. This study aimed to determine hand coverage for three handrubs (two gels based on 70% v/v and 85% w/w ethanol and a foam based on 70% v/v ethanol) applied at various volumes. Products were tested at product volumes of 1.1 mL, 2 mL, 2.4 mL as well as 1 and 2 pump dispenser pushes; the foam product was tested in addition at foam volumes of 1.1 mL, 2 mL, and 2.4 mL. Products were supplemented with a fluorescent dye and 15 participants applied products using responsible application techniques without any specific steps but the aim of completely covering both hands. Coverage quality was determined under ultraviolet light by two blinded investigators. Efficacy of the three handrubs was determined according to ASTM E 1174-06 and ASTM E 2755-10. For each experiment, the hands of 12 participants were contaminated with Serratia marcescens and the products applied as recommended (1.1 mL for 70% v/v ethanol products; 2 mL for the 85% w/w ethanol product). Log10-reduction was calculated. Volumes < 2 mL yielded high rates of incomplete coverage (67%-87%) whereas volumes ≥ 2 mL gave lower rates (13%-53%). Differences in coverage were significant between the five volumes tested for all handrubs (p < 0.001; two-way ANOVA) but not between the three handrubs themselves (p = 0.796). Application of 1.1 mL of 70% v/v ethanol rubs reduced contamination by 1.85 log10 or 1.60 log10 (ASTM E 1174-06); this failed the US FDA efficacy requirement of at least 2 log10. Application of 2 mL of the 85% w/w ethanol rub reduced contamination by 2.06 log10 (ASTM E 1174-06), fulfilling the US FDA efficacy requirement. Similar results were obtained according to ASTM E 2755-10. Our data indicated that handrubs based on 70% ethanol (v/v) with a recommended volume of 1.1 mL per application do not ensure complete coverage of both hands and do not achieve current ASTM efficacy standards.
-
40 CFR 141.715 - Microbial toolbox options for meeting Cryptosporidium treatment requirements.
Code of Federal Regulations, 2010 CFR
2010-07-01
... filter performance 0.5-log credit for combined filter effluent turbidity less than or equal to 0.15 NTU...) Individual filter performance 0.5-log credit (in addition to 0.5-log combined filter performance credit) if individual filter effluent turbidity is less than or equal to 0.15 NTU in at least 95 percent of samples each...
-
40 CFR 141.715 - Microbial toolbox options for meeting Cryptosporidium treatment requirements.
Code of Federal Regulations, 2011 CFR
2011-07-01
... filter performance 0.5-log credit for combined filter effluent turbidity less than or equal to 0.15 NTU...) Individual filter performance 0.5-log credit (in addition to 0.5-log combined filter performance credit) if individual filter effluent turbidity is less than or equal to 0.15 NTU in at least 95 percent of samples each...
-
40 CFR 141.715 - Microbial toolbox options for meeting Cryptosporidium treatment requirements.
Code of Federal Regulations, 2012 CFR
2012-07-01
... filter performance 0.5-log credit for combined filter effluent turbidity less than or equal to 0.15 NTU...) Individual filter performance 0.5-log credit (in addition to 0.5-log combined filter performance credit) if individual filter effluent turbidity is less than or equal to 0.15 NTU in at least 95 percent of samples each...
-
Federal Register 2010, 2011, 2012, 2013, 2014
2010-02-01
... V H less than or equal to 87 knots CAS. 8. Remove the requirement for all flight instructors to log... certificate must log within 60 days prior to taking the practical test. 16. Remove expired ultralight... flight training an applicant for a sport pilot certificate must log within the preceding 2 calendar...
-
R. Edward Thomas
2013-01-01
Determining the defects located within a log is crucial to understanding the tree/log resource for efficient processing. However, existing means of doing this non-destructively requires the use of expensive x-ray/CT (computerized tomography), MRI (magnetic resonance imaging), or microwave technology. These methods do not lend themselves to fast, efficient, and cost-...
-
Tinidazole inhibitory and cidal activity against anaerobic periodontal pathogens.
Alou, L; Giménez, M J; Manso, F; Sevillano, D; Torrico, M; González, N; Granizo, J J; Bascones, A; Prieto, J; Maestre, J R; Aguilar, L
2009-05-01
The in vitro activity of tinidazole against anaerobic periodontal pathogens (25 Prevotella buccae, 18 Prevotella denticola, 10 Prevotella intermedia, 6 Prevotella melaninogenica, 5 Prevotella oralis, 10 Fusobacterium nucleatum and 8 Veillonella spp.) was determined by agar dilution. MIC(90) values (minimum inhibitory concentration for 90% of the organisms) were 8 microg/mL for Veillonella spp., 4 microg/mL for P. intermedia, 2 microg/mL for P. buccae, 1 microg/mL for Fusobacterium spp. and 0.5 microg/mL for other Prevotella spp. Cidal activity was studied by killing curves with tinidazole and amoxicillin (alone and in combination) at concentrations similar to those achieved in crevicular fluid (41.2 microg/mL tinidazole and 14.05 microg/mL amoxicillin) against an inoculum of ca. 10(7)colony-forming units/mL of four bacterial groups, each one composed of four different strains of the following periodontal isolates: Prevotella spp., Fusobacterium spp. and Veillonella spp. (anaerobes) and one amoxicillin-susceptible Streptococcus spp. (facultative) in a proportion of 1:1:1:1. When only beta-lactamase-negative Prevotella or Fusobacterium strains were tested, significantly higher reductions were found with amoxicillin (>4 log reduction at 48 h) versus controls. The presence of beta-lactamase-positive Prevotella spp. or F. nucleatum strains rendered amoxicillin inactive (no reductions at 48 h), with no differences from controls. Amoxicillin+tinidazole produced >3 log reduction at 24h and >4 log reduction at 48 h regardless of the presence or not of beta-lactamase-positive strains. The presence in crevicular fluid of beta-lactamases produced by beta-lactamase-positive periodontal pathogens may have ecological and therapeutic consequences since it may protect beta-lactamase-negative periodontal pathogens from amoxicillin treatment. In vitro, tinidazole offered high antianaerobic activity against beta-lactamase-positive and -negative periodontal pathogens, avoiding amoxicillin inactivation.
-
Natural inactivation of Escherichia coli in anoxic and reduced groundwater
Lisle, John T.
2016-01-01
Aquifer recharge zones with geochemical characteristics observed in this study complement above ground engineered processes (e.g., filtration, disinfection), while increasing the overall indicator microorganism log-reduction rate of a facility.
-
Fisher, K; Rowe, C; Phillips, C A
2007-05-01
To test the effect of oils and vapours of lemon, sweet orange and bergamot and their components against three Arcobacter butzleri strains. The disc diffusion method was used to screen the oils and vapours against three strains of A. butzleri. In vitro bergamot was the most inhibitory essential oil (EO) and both citral and linalool were effective. On cabbage leaf, the water isolate was the least susceptible to bergamot EO, citral and linalool (1-2 log reduction), with the chicken isolate being the most susceptible (6-8 log reduction). However, the latter appeared not to be susceptible to vapours over 24 h although type strain and water isolate populations reduced by 8 logs. On chicken skin, the effectiveness of the oils was reduced compared with that on cabbage leaf. Bergamot was the most effective of the oils tested and linalool the most effective component. All strains tested were less susceptible in food systems than in vitro. Arcobacter isolates vary in their response to EO suggesting that the results of type strain studies should be interpreted with caution. Bergamot EO has the potential for the inhibition of this 'emerging' pathogen.
-
Clinical use of photodynamic antimicrobial chemotherapy for the treatment of deep carious lesions
NASA Astrophysics Data System (ADS)
Guglielmi, Camila De Almeida B.; Simionato, Maria Regina L.; Ramalho, Karen Müller; Imparato, José Carlos P.; Pinheiro, Sérgio Luiz; Luz, Maria A. A. C.
2011-08-01
The purpose of this study was to assess photodynamic antimicrobial chemotherapy (PACT) via irradiation, using a low power laser associated with a photosensitization dye, as an alternative to remove cariogenic microorganisms by drilling. Remaining dentinal samples in deep carious lesions on permanent molars (n = 26) were treated with 0.01% methylene blue dye and irradiated with a low power laser (InGaAIP - indium gallium aluminum phosphide; λ = 660 nm; 100 mW; 320 Jcm-2 90 s; 9J). Samples of dentin from the pulpal wall region were collected with a micropunch before and immediately after PACT and kept in a transport medium for microbiological analysis. Samples were cultured in plates of Brucella blood agar, Mitis Salivarius Bacitracin agar and Rogosa SL agar to determine the total viable bacteria, mutans streptococci and Lactobacillus spp. counts, respectively. After incubation, colony-forming units were counted and microbial reduction was calculated for each group of bacteria. PACT led to statistically significant reductions in mutans streptococci (1.38 log), Lactobacillus spp. (0.93 log), and total viable bacteria (0.91 log). This therapy may be an appropriate approach for the treatment of deep carious lesions using minimally invasive procedures.
-
In Vitro and In Vivo Synergy of the Oxadiazole Class of Antibacterials with β-Lactams.
Janardhanan, Jeshina; Meisel, Jayda E; Ding, Derong; Schroeder, Valerie A; Wolter, William R; Mobashery, Shahriar; Chang, Mayland
2016-09-01
The oxadiazole antibacterials target the bacterial cell wall and are bactericidal. We investigated the synergism of ND-421 with the commonly used β-lactams and non-β-lactam antibiotics by the checkerboard method and by time-kill assays. ND-421 synergizes well with β-lactam antibiotics, and it also exhibits a long postantibiotic effect (4.7 h). We also evaluated the in vivo efficacy of ND-421 in a murine neutropenic thigh infection model alone and in combination with oxacillin. ND-421 has in vivo efficacy by itself in a clinically relevant infection model (1.49 log10 bacterial reduction for ND-321 versus 0.36 log10 for linezolid with NRS119) and acts synergistically with β-lactam antibiotics in vitro and in vivo, and the combination of ND-421 with oxacillin is efficacious in a mouse neutropenic thigh methicillin-resistant Staphylococcus aureus (MRSA) infection model (1.60 log10 bacterial reduction). The activity of oxacillin was potentiated in the presence of ND-421, as the strain would have been resistant to oxacillin otherwise. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
-
Nei, Daisuke; Enomoto, Katsuyoshi; Nakamura, Nobutaka
2015-08-01
Contamination of spices by pathogenic and/or spoilage bacteria can be deleterious to consumer's health and cause deterioration of foods, and inactivation of such bacteria is necessary for the food industry. The present study examined the effect of gaseous acetic acid treatment in reducing Escherichia coli O157:H7, Salmonella Enteritidis and Bacillus subtilis populations inoculated on fenugreek seeds and black pepper. Treatment with gaseous acetic acid at 0.3 mmol/L, 0.6 mmol/L and 4.7 mmol/L for 1-3 h significantly reduced the populations of E. coli O157:H7 and Salmonella Enteritidis on black pepper and fenugreek seeds at 55 °C (p < 0.05). The gas treatments at 4.7 mmol/L were more effective in inactivating the pathogens than the treatment at 0.3 mmol/L. An approximately 5.0 log reduction was obtained after 3 h of treatment with 4.7 mmol/L acetic acid. No significant reductions in the population of B. subtilis spores inoculated on fenugreek seeds and black pepper were obtained after the gas treatments at 0.3 mmol/L or 0.6 mmol/L (p > 0.05). However, the gas treatment at 4.7 mmol/L significantly reduced B. subtilis spores (p < 0.05), and 4.0 log CFU/g and 3.5 log CFU/g reductions on fenugreek seeds and black pepper, respectively, were obtained after 3 h of treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.
-
Han, Jung H; Patel, Dhaval; Kim, Jung Eun; Min, Sea C
2014-11-01
An antimicrobial sachet containing microcellular foam starch (MFS) with embedded rosemary oil and thyme oil was developed to reduce bacterial growth in shredded mozzarella cheese. The efficacy of the volatiles of oils at various concentrations in reducing Listeria monocytogenes as well as the release of the oils from the MFS have been also determined in this study. The cheese, inoculated with a cocktail of 5 strains of L. monocytogenes (approximately 3 log CFU/g), was packaged in a Nylon/EVOH/PE bag. A paper sachet containing MFS embedded with rosemary oil and thyme oil, separately or together, was inserted into the bag. Rosemary and thyme oil volatiles released from the sachet restricted the growth of L. monocytogenes, resulting in a 2.5 log CFU/g reduction on day 9 at 10 °C. The volatile oils also showed inhibitory effects on the growth of lactic acid bacteria (LAB) and total aerobic bacteria (TAB). After 15 d at 10 °C, the numbers of LAB and TAB in the samples containing the sachet with both oils experienced a 1.2 and 1.4 log CFU/g reduction, respectively, compared to untreated samples. Nonetheless, the sachet treatment produced a distinct odor, unfavorably received by the panelists. The results suggest the potential for application of the sachet system for the reduction of growth of L. monocytogenes, LAB, and TAB in food products. © 2014 Institute of Food Technologists®
-
Lindenmayer, D B; Ought, K
2006-08-01
The two major forms of disturbance in the montane ash eucalypt forests of the Central Highlands of Victoria (southeastern Australia) are clearfell logging and unplanned wildfires. Since the 1930s wildfire has been followed by intensive and extensive salvage-logging operations, which may proceed for many years after a wildfire has occurred. Although applied widely, the potential effects of salvage logging on native flora and fauna have been poorly studied. Our data indicate that the abundance of large trees with hollows is significantly reduced in forests subject to salvage harvesting. This has implications for thepersistence of an array of such cavity-using vertebrates as the endangered arboreal marsupial, Leadbeater's possum (Gymnobelidues leadbeateri). Salvage logging also reduces the prevalence of multiaged montane ash forests--places that typically support the highest diversity of arboreal marsupials and forest birds. Limited research has been conducted on the effects of salvage logging on plants; thus, we constructed hypotheses about potential impacts for further testing based on known responses to clearfell logging and key life history attributes. We predict many species, such as vegetatively resprouting tree ferns, will decline, as they do after clearfelling. We also suggest that seed regenerators, which typically regenerate well after fire or conventional clearfelling, will decline after salvage logging because the stimulation for germination (fire) takes place prior to mechanical disturbance (logging). Understoryplant communities in salvage-logged areas will be dominated by a smaller suite of species, and those that are wind dispersed, have viable soil-stored seed remaining after salvage logging, or have deep rhizomes are likely to be advantaged. We recommend the following improvements to salvage-logging policies that may better incorporate conservation needs in Victorian montane ash forests: (1) exemption of salvage logging from some areas (e.g., old-growth stands and places subject to only partial stand damage); (2) increased retention of biological legacies on burned areas through variations in the intensity of salvage logging; and (3) reduction in the levels of physical disturbance on salvage-logged areas, especially through limited seedbed preparation and mechanical disturbance.
-
Vinson, C C; Kanashiro, M; Sebbenn, A M; Williams, T C R; Harris, S A; Boshier, D H
2015-08-01
The impact of logging and subsequent recovery after logging is predicted to vary depending on specific life history traits of the logged species. The Eco-gene simulation model was used to evaluate the long-term impacts of selective logging over 300 years on two contrasting Brazilian Amazon tree species, Dipteryx odorata and Jacaranda copaia. D. odorata (Leguminosae), a slow growing climax tree, occurs at very low densities, whereas J. copaia (Bignoniaceae) is a fast growing pioneer tree that occurs at high densities. Microsatellite multilocus genotypes of the pre-logging populations were used as data inputs for the Eco-gene model and post-logging genetic data was used to verify the output from the simulations. Overall, under current Brazilian forest management regulations, there were neither short nor long-term impacts on J. copaia. By contrast, D. odorata cannot be sustainably logged under current regulations, a sustainable scenario was achieved by increasing the minimum cutting diameter at breast height from 50 to 100 cm over 30-year logging cycles. Genetic parameters were only slightly affected by selective logging, with reductions in the numbers of alleles and single genotypes. In the short term, the loss of alleles seen in J. copaia simulations was the same as in real data, whereas fewer alleles were lost in D. odorata simulations than in the field. The different impacts and periods of recovery for each species support the idea that ecological and genetic information are essential at species, ecological guild or reproductive group levels to help derive sustainable management scenarios for tropical forests.
-
Vinson, C C; Kanashiro, M; Sebbenn, A M; Williams, T CR; Harris, S A; Boshier, D H
2015-01-01
The impact of logging and subsequent recovery after logging is predicted to vary depending on specific life history traits of the logged species. The Eco-gene simulation model was used to evaluate the long-term impacts of selective logging over 300 years on two contrasting Brazilian Amazon tree species, Dipteryx odorata and Jacaranda copaia. D. odorata (Leguminosae), a slow growing climax tree, occurs at very low densities, whereas J. copaia (Bignoniaceae) is a fast growing pioneer tree that occurs at high densities. Microsatellite multilocus genotypes of the pre-logging populations were used as data inputs for the Eco-gene model and post-logging genetic data was used to verify the output from the simulations. Overall, under current Brazilian forest management regulations, there were neither short nor long-term impacts on J. copaia. By contrast, D. odorata cannot be sustainably logged under current regulations, a sustainable scenario was achieved by increasing the minimum cutting diameter at breast height from 50 to 100 cm over 30-year logging cycles. Genetic parameters were only slightly affected by selective logging, with reductions in the numbers of alleles and single genotypes. In the short term, the loss of alleles seen in J. copaia simulations was the same as in real data, whereas fewer alleles were lost in D. odorata simulations than in the field. The different impacts and periods of recovery for each species support the idea that ecological and genetic information are essential at species, ecological guild or reproductive group levels to help derive sustainable management scenarios for tropical forests. PMID:24424164
-
Thermal inactivation of Salmonella spp. in pork burger patties.
Gurman, P M; Ross, T; Holds, G L; Jarrett, R G; Kiermeier, A
2016-02-16
Predictive models, to estimate the reduction in Escherichia coli O157:H7 concentration in beef burgers, have been developed to inform risk management decisions; no analogous model exists for Salmonella spp. in pork burgers. In this study, "Extra Lean" and "Regular" fat pork minces were inoculated with Salmonella spp. (Salmonella 4,[5],12,i:-, Salmonella Senftenberg and Salmonella Typhimurium) and formed into pork burger patties. Patties were cooked on an electric skillet (to imitate home cooking) to one of seven internal temperatures (46, 49, 52, 55, 58, 61, 64 °C) and Salmonella enumerated. A generalised linear logistic regression model was used to develop a predictive model for the Salmonella concentration based on the internal endpoint temperature. It was estimated that in pork mince with a fat content of 6.1%, Salmonella survival will be decreased by -0.2407log10 CFU/g for a 1 °C increase in internal endpoint temperature, with a 5-log10 reduction in Salmonella concentration estimated to occur when the geometric centre temperature reaches 63 °C. The fat content influenced the rate of Salmonella inactivation (P=0.043), with Salmonella survival increasing as fat content increased, though this effect became negligible as the temperature approached 62 °C. Fat content increased the time required for patties to achieve a specified internal temperature (P=0.0106 and 0.0309 for linear and quadratic terms respectively), indicating that reduced fat pork mince may reduce the risk of salmonellosis from consumption of pork burgers. Salmonella serovar did not significantly affect the model intercepts (P=0.86) or slopes (P=0.10) of the fitted logistic curve. This predictive model can be applied to estimate the reduction in Salmonella in pork burgers after cooking to a specific endpoint temperature and hence to assess food safety risk. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.
-
Petti, S; Messano, G A
2016-05-01
Traditional cleaning and disinfection methods are inefficient for complete decontamination of hospital surfaces from meticillin-resistant Staphylococcus aureus (MRSA). Additional methods, such as nano-TiO2-based photocatalytic disinfection (PCD), could be helpful. To evaluate anti-MRSA activity of PCD on polyvinyl chloride (PVC) surfaces in natural-like conditions. Two identical PVC surfaces were used, and nano-TiO2 was incorporated into one of them. The surfaces were contaminated with MRSA isolated from hospitalized patients using a mist sprayer to simulate the mode of environmental contamination caused by a carrier. MRSA cell density was assessed before contamination until 180min after contamination using Rodac plates. The differences between test and control surfaces in terms of MRSA density and log MRSA density reduction were assessed using parametric and non-parametric statistical tests. Five strains were tested, and each strain was tested five times. The highest median MRSA densities [46.3 and 43.1 colony-forming units (cfu)/cm(2) for control and test surfaces, respectively] were detected 45min after contamination. Median MRSA densities 180min after contamination were 10.1 and 0.7cfu/cm(2) for control and test surfaces, respectively (P<0.01). Log MRSA density reduction attributable to PCD was 1.16logcfu/cm(2), corresponding to 93% reduction of the baseline MRSA contamination. The disinfectant activity remained stable throughout the 25 testing occasions, despite between-test cleaning and disinfection. The anti-MRSA activity of PCD was compatible with the benchmark for surface hygiene in hospitals (<1cfu/cm(2)), but required 3h of exposure to photocatalysis. Thus, PCD could be considered for non-clinical surfaces. However, for clinical surfaces, PCD should be regarded as supplemental to conventional decontamination procedures, rather than an alternative. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
-
Sommers, Christopher H; Cooke, Peter H
2009-04-01
Yersinia pestis is the causative agent of plague. Although rare, pharyngeal plague in humans has been associated with consumption or handling of meat prepared from infected animals. The risks of contracting plague from consumption of deliberately contaminated food are currently unknown. Gamma radiation is a penetrating form of electromagnetic radiation, and UVC radiation is used for decontamination of liquids or food surfaces. Gamma radiation D10-values (the radiation dose needed to inactivate 1 log unit pathogen) were 0.23 (+/-0.01) and 0.31 (+/-0.03) kGy for avirulent Y. pestis inoculated into Butterfield's phosphate buffer and onto frankfurter surfaces, respectively, at 0 degree C. A UVC radiation dose of 0.25 J/cm2 inactivated avirulent Y. pestis suspended in Butterfield's phosphate buffer. UVC radiation doses of 0.5 to 4.0 J/cm2 inactivated 0.97 to 1.20 log units of the Y. pestis surface inoculated onto frankfurters. A low gamma radiation dose of 1.6 kGy could provide a 5-log reduction and a UVC radiation dose of 1 to 4 J/cm2 would provide a 1-log reduction of Y. pestis surface inoculated onto frankfurters. Y. pestis was capable of growth on frankfurters during refrigerated storage (10 degrees C). Gamma radiation of frankfurters inhibited the growth of Y. pestis during refrigerated storage, and UVC radiation delayed the growth of Y. pestis.
-
Walkling-Ribeiro, Markus; Anany, Hany; Griffiths, Mansel W
2015-01-01
Pulsed electric fields (PEF), heat-assisted PEF (H-PEF), and virulent bacteriophage (VP) are non-thermal techniques for pathogen inactivation in liquids that were investigated individually, and in combination (PEF/VP, H-PEF/VP) to control enterohemorrhagic Escherichia coli (EHEC) O157:H7 in Luria-Bertani broth (LBB) and Ringer's solution (RS). Treated cells were subsequently incubated at refrigeration (4°C) and temperature-abuse conditions (12°C) for 5 days. When EHEC cells grown in LBB were subjected to non-thermal processing and subsequently stored at 12°C for 5 days, reductions in count of between 0.1 and 0.6 log cycles were observed and following storage at 4°C the decrease in counts varied between 0.2 and 1.1 log10 . For bacteria cells suspended in RS values ranged from 0.1 to ≥3.9 log cycles at both storage temperatures. The most effective treatments were H-PEF and H-PEF/VP, both producing a >3.4 log cycle reduction of cells suspended in non-nutrient RS. Analysis of EHEC recovery on selective and non-selective media indicated no occurrence of sub-lethal damage for VP, PEF/VP, and H-PEF/VP-treated cells. The findings indicate that combining PEF and lytic phage may represent a suitable alternative to conventional fluid decontamination following further process optimization. © 2014 American Institute of Chemical Engineers.
-
Maltodextrin enhances biofilm elimination by electrochemical scaffold
Sultana, Sujala T.; Call, Douglas R.; Beyenal, Haluk
2016-01-01
Electrochemical scaffolds (e-scaffolds) continuously generate low concentrations of H2O2 suitable for damaging wound biofilms without damaging host tissue. Nevertheless, retarded diffusion combined with H2O2 degradation can limit the efficacy of this potentially important clinical tool. H2O2 diffusion into biofilms and bacterial cells can be increased by damaging the biofilm structure or by activating membrane transportation channels by exposure to hyperosmotic agents. We hypothesized that e-scaffolds would be more effective against Acinetobacter baumannii and Staphylococcus aureus biofilms in the presence of a hyperosmotic agent. E-scaffolds polarized at −600 mVAg/AgCl were overlaid onto preformed biofilms in media containing various maltodextrin concentrations. E-scaffold alone decreased A. baumannii and S. aureus biofilm cell densities by (3.92 ± 0.15) log and (2.31 ± 0.12) log, respectively. Compared to untreated biofilms, the efficacy of the e-scaffold increased to a maximum (8.27 ± 0.05) log reduction in A. baumannii and (4.71 ± 0.12) log reduction in S. aureus biofilm cell densities upon 10 mM and 30 mM maltodextrin addition, respectively. Overall ~55% decrease in relative biofilm surface coverage was achieved for both species. We conclude that combined treatment with electrochemically generated H2O2 from an e-scaffold and maltodextrin is more effective in decreasing viable biofilm cell density. PMID:27782161
-
Ortega-Ramirez, Luis A; Silva-Espinoza, Brenda A; Vargas-Arispuro, Irasema; Gonzalez-Aguilar, Gustavo A; Cruz-Valenzuela, M Reynaldo; Nazzaro, Filomena; Ayala-Zavala, J Fernando
2017-05-01
Cymbopogon citratus and Allium cepa essential oils (EOs) are rich in terpenes and sulfur compounds respectively, both with antibacterial activity and different cell targets, supporting the idea that their combination can increase their efficacy. Major constituents of C. citratus were geranial and neral, while A. cepa presented dipropyl disulfide and dipropyl trisulfide. Cymbopogon citratus and A. cepa EOs inhibited the in vitro growth of Escherichia coli O157:H7 (minimal inhibitory concentrations of 2.21 and 5.13 g L -1 respectively), Salmonella Choleraesuis (3.04 and 1.28 g L -1 ), Listeria monocytogenes (1.33 and 2.56 g L -1 ) and Staphylococcus aureus (0.44 and 5.26 g L -1 ). Application of the EO combination to spinach caused a greater reduction in E. coli (2.34 log colony-forming units (CFU) g -1 ), S. Choleraesuis (2.94 log CFU g -1 ), L. monocytogenes (2.06 log CFU g -1 ) and S. aureus (1.37 log CFU g -1 ) compared with higher doses of individual EOs; a similar effect was observed for romaine lettuce. Individual and combined EOs caused a reduction in flavor acceptability level; however, no significant differences were found among odor acceptability of control vegetables and those treated with the EO combination and C. citratus EO. Leafy vegetables treated with the EO combination showed higher antibacterial protection and odor acceptability compared with individual EO treatments. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.