The SARS-CoV-2 pandemic has presented new challenges to food manufacturers. During the early phase of the pandemic, several large outbreaks of coronavirus disease 2019 (COVID-19) occurred in food manufacturing plants resulting in deaths and economic loss, with approximately 15% of personnel diagnosed as asymptomatic for COVID-19. Spread by asymptomatic and presymptomatic individuals has been implicated in large outbreaks of COVID-19. In March 2020, we assisted in implementation of environmental monitoring programs for SARS-CoV-2 in zones 3 and 4 of 116 food production facilities. All participating facilities had already implemented measures to prevent symptomatic personnel from coming to work. During the study period, from 17 March to 3 September 2020, 1.23% of the 22,643 environmental samples tested positive for SARS-CoV-2, suggesting that infected individuals were actively shedding virus. Virus contamination was commonly found on frequently touched surfaces such as doorknobs, handles, table surfaces, and sanitizer dispensers. Most processing plants managed to control their environmental contamination when they became aware of the positive findings. Comparisons of positive test results for plant personnel and environmental surfaces in one plant revealed a close correlation. Our work illustrates that environmental monitoring for SARS-CoV-2 can be used as a surrogate for identifying the presence of asymptomatic and presymptomatic personnel in workplaces and may aid in controlling infection spread. HIGHLIGHTS
Vibrio parahaemolyticus infections in the United States have been linked to consumption of raw oysters. Depuration has the potential to reduce contamination in live oysters after harvest. This study investigated the impact of depuration flow rate to reduce V. parahaemolyticus in raw oysters. Pacific oysters (n = 35 per trial) were inoculated with a cocktail of V. parahaemolyticus (10290, 10292, 10293, BE 98‐2029, and 027‐1c1) in freshly prepared artificial seawater (70 L). The inoculated oysters were depurated with flow rates of 15, 20, 25, and 35 L/min at 12.5 °C for up to 5 days and V. parahaemolyticus contamination was determined using a three‐tube most probable number (MPN) method. V. parahaemolyticus reductions were as flow rate moderately increased from 15 L/min (2.39 log MPN/g reduction in 5 days) to 35 L/min (3.39 log MPN/g reduction). These results suggest that depuration efficacy can be enhanced by increasing depuration flow rate to 35 L/min. Practical applications Vibrio parahaemolyticus can contaminate raw shellfish, including oysters, during their production and lead to outbreaks of foodborne illness. Depuration, a post‐harvest process, may be used by the shellfish industry to reduce the persistence of V. parahaemolyticus. Previous studies have demonstrated that the depuration process can reduce V. parahaemolyticus in oysters; however, further optimization of the process is necessary to achieve US Food Drug Administration's targeted reduction goal (>3.52 log MPN/g). This study evaluated the impact of depuration flow rate on the reduction of V. parahaemolyticus in Pacific oysters. Increasing flow rates (15–35 L/min) during depuration enhanced the clearance of V. parahaemolyticus in these oysters; however, these conditions were unable to consistently achieve the target of >3.52 log MPN/g reduction. This study provides a reference for the industry on the variability of V. parahaemolyticus in individual oysters and demonstrates that practical modifications (i.e., flow rate) can be implemented in depuration systems to maximize bacterial clearance.
The SARS-CoV-2 pandemic has presented new challenges to food manufacturers. In addition to preventing the spread of microbial contamination of food, with SARS-CoV-2, there is an additional focus on preventing SARS-CoV-2 infections in food plant personnel. During the early phase of the pandemic, several large outbreaks of Covid-19 occurred in food manufacturing plants resulting in deaths and economic loss. In March of 2020, we assisted in implementation of environmental monitoring programs for SARS-CoV-2 in 116 food production facilities. All participating facilities had already implemented measures to prevent symptomatic personnel from coming to work. During the study period, from March 17, 2020 to September 3, 2020, 1.23% of the 22,643 environmental samples tested positive for SARS-CoV-2, suggesting that infected individuals are actively shedding virus. Virus contamination was commonly found on frequently touched surfaces. Most plants managed to control their environmental contamination when they became aware of the positive findings. Comparisons of the personnel test results to environmental contamination in one plant showed a good correlation between the two. Our work illustrates that environmental monitoring for SARS-CoV-2 can be used as a surrogate for identifying the presence of asymptomatic and pre-symptomatic personnel in workplaces and may aid in controlling infection spread.HighlightsEnvironmental contamination by SARS-CoV-2 virus was detected in food plantsOut of 22,643 environmental swabs, 278 (1.23%) were positive for SARS-CoV-2Frequently touched surfaces had the most contaminationSurface testing for SARS-CoV-2 may indicate presence of asymptomatic carriers
Background The Enterobacteriaceae and generic Escherichia coli are routinely enumerated in foods as part of product release criteria, or in the case of swabs, for environmental monitoring. Objective Microbiologique Microfilm™ EBEc is intended to provide a rapid and easy-to-use method for simultaneous enumeration of Enterobacteriaceae and E. coli on foods and environmental surfaces. Methods: This study evaluated the performance of Microfilm™ EBEc against ISO methods (ISO 21528-2:2017 for Enterobacteriaceae and ISO 16649-2: 2001 for E. coli) in 20 food matrixes and two environmental surfaces. Inclusivity, exclusivity, lot-to-lot reproducibility, ruggedness and stability studies were also performed on Microfilm™ EBEc. Results No significant differences and high correlation coefficients (R2) were observed between the Microfilm™ EBEc and the corresponding ISO methods in spiked food matrixes and environmental samples. Inclusivity studies showed expected results for all the E. coli and Enterobacteriaceae strains tested. In terms of exclusivity testing, all the strains tested failed to grow on Microfilm™ EBEc. A lot-to-lot study showed no significant differences in mean difference (log10) counts among the three lots of the Microfilm™ EBEc. Ruggedness studies showed no significant differences in mean difference (log10) counts at varying incubation temperatures and times. Stability studies on the Microfilm™ EBEc showed that it is stable at 2–25°C for 12 months, and at 45°C for 6 weeks. Conclusions The results of this study indicate that the Microfilm™ EBEc is equivalent to the corresponding ISO methods for enumeration of Enterobacteriaceae and E. coli. Highlights: Microfilm™ EBEc offers a convenient and relatively fast test method for simultaneous enumeration of Enterobacteriaceae and E. coli in 24 h and has an advantage over the corresponding ISO methods that require two assays on the same sample for enumeration of Enterobacteriaceae and E. coli Gram-negative indicator groups.
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