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Why was the work done: To (i) determine whether microbial pathogens were present in packaged alcohol-free and low alcohol beers, (ii) to assess whether pathogens can survive or grow in non-alcoholic beers, and (iii) to determine the impact of pH and bitterness on their growth and survival of pathogens in alcoholfree beer. How was the work done:: 50 alcohol-free and low alcohol beers, available in the UK, were screened for pathogens and analysed for ABV, pH and bitterness (IBU). One of the alcohol-free beers (with the lowest IBU) was adjusted to 25 and 50 IBU and pH 3.8, 4.2, 4.6 and 4.9. Challenge testing of these beers was performed with Escherichia coli O157, Salmonella Enteritidis, Bacillus cereus and Clostridium botulinum. In addition, the heat resistance (D60 value) of the pathogens, spoilage bacteria and Saccharomyces cerevisiae ascospores in these beers was determined. What are the main findings: Salmonella, E. coli, Enterobacteriaceae, Bacillus cereus and sulphite reducing Clostridia were not found in any of the 50 beers. However, two emerging opportunistic pathogens (Cupriavidus gilardii and Sphingomonas paucimobilis) were found in the low alcohol keg beers. None of the pathogens used in this study could grow in the alcohol-free beer at low pH (pH 3.8). E. coli O157 was unable to grow at pH 4.2 but could grow at pH 4.6 but only with reduced levels of carbon dioxide and increased oxygen. Salmonella Enteritidis was able to grow at pH 4.2 and 4.6 but also with reduced levels of CO2 and increased O2. Although Bacillus cereus and C. botulinum were unable to grow in any of the tested conditions, both pathogens were able to survive. Survival and/or growth of the microorganisms was impacted by pH; bitterness had no effect. Why is the work important: Salmonella Enteritidis and E. coli O157 only grew in alcohol free beer at a higher pH (4.2 and 4.6 for Salmonella and 4.6 for E. coli) together with with reduced levels of CO2 and increased O2. This suggests that packaged beer with appreciable levels of carbon dioxide and negligible levels of oxygen will not support the growth of pathogens. However, draught alcohol free beer may be vulnerable to pathogens. [ABSTRACT FROM AUTHOR]

Background: The CompactDry "Nissui" YMR is a ready-to-use dry media sheet using a chromogenic medium with selective agents for the detection and enumeration of yeasts and molds in products after incubation at 256 ± 1°C for 3 days. Objective: The CompactDry "Nissui" YMR method was validated in order to achieve AOAC Performance Tested Methods℠ certification. Method: The performance of the CompactDry "Nissui" YMR was compared to that of ISO 21527-1:2008 for 10 matrixes including cooked prawns, deli vegetable salad, tuna pâté, fermented yogurt drink, spinach and ricotta quiche, egg custard tarts, fruit and vegetable smoothie, cream cheese, egg salad sandwich, and deli pasta salad. Performance indicators included repeatability, difference of means (DOM), and inclusivity/exclusivity. Results: After log10 transformation of the data, the relative standard deviation of repeatability (RSDr) was <10% for all 30 materials (10 matrixes each at 3 levels) analyzed by the CompactDry "Nissui" YMR method and for 29 of the 30 matrix/level combinations analyzed by the reference method. The DOM ranged from -0.284 (-0.310, -0.257) log10 CFU/g to 0.307 (-0.013, 0.627) log10 CFU/g. Method equivalence was demonstrated in 29 of the 30 matrix/level combinations based on the 90% confidence interval of the DOM being within (-0.5, 0.5). All 51 inclusivity strains showed expected or atypical results, and all 32 exclusivity organisms showed no growth on the medium. The method was shown to be robust to changes in sample volume, incubation temperature, and incubation time, and data are presented supporting product consistency and a 24-month shelf life. Conclusions: The CompactDry "Nissui" YMR method is validated for the determination of yeasts and molds in a variety of matrixes. Highlights: The CompactDry "Nissui" YMR method is equivalent to the ISO 21527-1:2008 reference method and is suitable for Performance Tested MethodsSM certification for the matrixes tested. [ABSTRACT FROM AUTHOR]

The MC-Media Pad ACplus™ is a dry, rehydratable film medium for the enumeration of aerobic bacterial colonies. The performance of the method in a variety of foods was compared to that of U.S. reference methods: U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) Microbiology Laboratory Guidebook (MLG) Chapter 3.02 "Quantitative Analysis of Bacteria in Foods as Sanitary Indicators" (USDA/FSIS MLG 3.02); Standard Methods for the Examination of Dairy Products (SMEDP) Chapter 6 "Microbiological Count Methods, Standard Plate Count Method" (SMEDP 6); AOAC Official MethodSM 966.23 Microbiological Methods; and ISO 4833-1:2013 "Microbiology of the food chain--Horizontal method for the enumeration of microorganisms--Part 1: Colony count at 30 degrees C by the pour plate technique." The validated matrixes included raw chicken breast and raw ground pork for USDA/FSIS MLG 3.02; cream cheese and yogurt drink for SMEDP 6; parsley, vegetable juice, prawns, tuna pate, sandwiches, and pasta salad for AOAC Method 966.23, and raw chicken breast, raw ground pork, cream cheese, yogurt drink, parsley, vegetable juice, prawns, tuna pate, sandwiches, and pasta salad for ISO 4833-1:2013. In each matrix study, five replicates at each of three contamination levels were tested as paired test portions. All 10 matrixes were compared to the appropriate U.S. reference methods under MC-Media Pad ACplus standard-usage conditions (35 ± 1°C for 48 ± 2 h). Across all matrixes, the difference of mean log10 values ranged from-0.43 to 0.44, within the acceptable range of -0.50 to 0.50. The candidatemethod repeatability SD (sr) varied from0.03 to 0.23 log10 CFU/g, comparing favorably to the reference method SD, which ranged from 0.06 to 0.30 log10 CFU/g. Seven matrixes were compared to the appropriate U.S. reference methods under MCMedia Pad ACplus rapid-usage conditions (35 ± 1°Cfor 24 ± 2 h).Of the 21 matrix/concentration combinations, only three instances of difference of mean >0.5 log were observed. The ranges of sr values of the rapid-usage candidatemethod (0.023-0.324) and the reference method (0.013-0.236) were similar for the seven matrixes tested. All 10 matrixes were compared to the International Organization for Standardization (ISO) reference method under MC-Media Pad ACplus alternate-method conditions (30 ± 1°C for 72 ± 3 h). All 10 matrixes yielded a mean difference between methods of <0.5 log, and the ranges of sr values were similar between the candidate alternate method (0.037-0.378) and the ISO reference method (0.037-0.437). The product consistency study demonstrated no significant difference between lots of product and supported the 2-year shelf life. Robustness testing yielded no significant differences when small variations were made in sample volume, incubation temperature, and incubation time. Thus, the data show equivalent or better performance of theMC-Media Pad ACplus method compared to the relevant reference methods in support of AOAC Performance Tested MethodSM certification. [ABSTRACT FROM AUTHOR]

MC-Media Pad SA (formerly known as Sanita-kun SA) is a dry rehydratable film medium for the enumeration of Staphylococcus aureus. The performance of the method in a variety of foods was compared with that of ISO 6888-1: 1999, Microbiology of Food and Animal Feeding Stuffs - Horizontal Method for the Enumeration of Coagulase-Positive Staphylococci (Staphylococcus aureus and Other Species) - Part 1: Technique Using Baird-Parker Agar Medium. The validated matrixes included pastrami, a sliced cooked chicken roll, cooked prawns, cold-smoked salmon, pasta salad, sandwich spread, fresh uncooked pasta, infant cereal, custard, and raw-milk Brie cheese. In the matrix study, five replicates at each of three contamination levels were tested as paired test portions. Across all matrixes, the difference in mean log10 values ranged from -0.32 to 0.10, which was within the acceptable range of -0.50 to 0.50. Thus, all 10 matrixes met the acceptance criterion at all concentration levels. Further, only two matrixes, cooked prawns and raw-milk Brie cheese, had 95% confidence limits outside the -0.50 to 0.50 criterion, and these were at the lowest concentration level for each matrix. The candidate method sr varied from 0.03 to 0.22 log10 CFU/g. This compares favorably with the reference method SD, which ranged from 0.06 to 0.30 log10 CFU/g. The candidate and reference methods detected 51 of 53 inclusivity strains, with both methods not detecting the same two strains. The candidate method did not detect any of the 32 exclusivity strains, whereas the reference method did not detect 30 of the 32 exclusivity strains; the 2 strains detected by the reference method were S. delphini and S. hyicus, both developing atypical colonies on Baird-Parker plates. The product consistency study demonstrated no significant difference between lots of product and supported the 1 year shelf life. Robustness testing yielded no significant differences when small variations were made in sample volume, incubation temperature, and incubation time. Thus, the data show equivalent or better performance of the Sanita-kun SA/MC-Media Pad SA method compared with the International Organization for Standardization reference method, in support of AOAC Performance Tested MethodSM certification. [ABSTRACT FROM AUTHOR]

Background: The CompactDry "Nissui" BC is a ready-to-use dry media sheet using a chromogenic medium with selective agents for the detection and enumeration of Bacillus cereus in products after incubation at 30±°C for 24±2h. Objective: The CompactDry "Nissui" BC method was validated to achieve AOAC Performance Tested Methods℠ certification. Method: The performance of the CompactDry "Nissui" BC was compared to that of ISO 7932:2004 for 10 matrixes, including panna cotta, double cream, dried baby food, dried vegetable soup mix, seafood sticks, salmon pa? te', sliced ham, pork liver pa? te', ham and cheese sandwich, and Caesar pasta salad with chicken and bacon. Performance indicators included repeatability, difference of means (DOM), and inclusivity/exclusivity. Results: After log10 transformation of the data, the relative standard deviation of repeatability (RSDr) was ≤9.2% for 28 of the 30 materials (10 matrixes each at three contamination levels) analyzed by the CompactDry "Nissui" BC method and ≤13% for 27 of the 30 matrix/level combinations analyzed by the reference method. Method equivalence was demonstrated in 28 of the 30 matrix/level combinations based on the 90% confidence interval of the DOM being within (-0.5, 0.5). For inclusivity, 47 of 50 strains tested showed typical colonies and confirmed positive. For exclusivity, 28 of 33 strains tested resulted in no growth or were negative, and five were positive. Inclusivity and exclusivity results were similar on the reference method agar. The method was shown to be robust to changes in sample volume, incubation temperature, and incubation time, and data are presented supporting product consistency and 18-month shelf life. Conclusions: The CompactDry "Nissui" BC method is validated for the determination of Bacillus cereus in a variety of matrixes. Highlights: The CompactDry "Nissui" BC method is equivalent to the ISO 7932:2004 reference method and is suitable for Performance Tested MethodsSM certification for the matrixes tested. [ABSTRACT FROM AUTHOR]

Background: SolerisVR Enterobacteriaceae is a growth-based, automated method for detection of Enterobacteriaceae in food. Objective: A study was conducted to validate the Soleris method for detection of Enterobacteriaceae in select foods (pasteurized milk, yogurt, mozzarella cheese, ice cream, dried milk, pasteurized liquid egg, frozen cooked chicken, deli ham, lettuce, and dry dog food) at a threshold of ≥ 10 CFU/g of product. Methods: Inclusivity and exclusivity of the Soleris method were assessed by testing 55 and 38 target and non-target bacterial strains, respectively. Matrix testing was performed with one naturally contaminated and nine inoculated foods. Efficacy of the Soleris method was compared to that of the ISO 21528-2:2017 direct plating reference method using probability of detection analysis. Independent laboratory testing was conducted to verify method performance in two matrixes (yogurt and deli ham). Method robustness, stability, and lot-to-lot consistency of the Soleris reagents were also assessed. Results: Inclusivity of the Soleris test was 91% and exclusivity was 100%. In matrix testing, there were no significant differences in the number of positive results obtained with the Soleris and reference methods for any of the matrixes examined. Overall, of 370 test portions, there were 176 positive results by the Soleris method and 177 positive results by the reference procedure. Conclusions: Soleris Enterobacteriaceae is an effective method for detection of Enterobacteriaceae in the foods evaluated, with performance equivalent to that of the ISO 21528-2:2017 reference method. Highlights: The Soleris method offers the advantages of labor savings and results within 18 h. [ABSTRACT FROM AUTHOR]