To culture or not to culture: careful assessment of metabarcoding data is necessary when evaluating the microbiota of a modified-atmosphere-packaged vegetarian meat alternative throughout its shelf-life period.

BACKGROUND: As the increased consumption of ready-to-eat meat alternatives is a fairly recent trend, little is known about the composition and dynamics of the microbiota present on such products. Such information is nonetheless valuable in view of spoilage and food safety prevention. Even though refrigeration and modified-atmosphere-packaging (MAP) can extend the shelf-life period, microbial spoilage can still occur in these products. In the present study, the microbiota of a vegetarian alternative to poultry-based charcuterie was investigated during storage, contrasting the use of a culture-dependent method to a culture-independent metagenetic method. RESULTS: The former revealed that lactic acid bacteria (LAB) were the most abundant microbial group, specifically at the end of the shelf-life period, whereby Latilactobacillus sakei was the most abundant species. Metabarcoding analysis, in contrast, revealed that DNA of Xanthomonas was most prominently present, which likely was an artifact due to the presence of xanthan gum as an ingredient, followed by Streptococcus and Weissella. CONCLUSIONS: Taken together, these results indicated that Lb. sakei was likely the most prominent specific spoilage organisms (SSO) and, additionally, that the use of metagenetic analysis needs to be interpreted with care in this specific type of product. In order to improve the performance of metagenetics in food samples with a high DNA matrix but a low bacterial DNA load, selective depletion techniques for matrix DNA could be explored.

Monitoring of Hygiene in Institutional Kitchens in Belgium.

ABSTRACT: Microbiological contamination of food during preparation and storage is a risk factor in institutional kitchens. In this Belgian study, hygiene practices in 40 institutional kitchens from four public sectors (10 hospitals, 10 schools, 10 retirement homes, and 10 child care centers) were evaluated to determine whether differences in these practices exist between these sectors. Contamination levels were also analyzed at several critical contact points. A data collection instrument and microbiological analysis of hand contact surfaces, food contact surfaces, and kitchen utensils were used. Hand washing resulted in only a slight reduction in total aerobic bacteria counts (TACs), and all microorganisms evaluated except E. coli were still present at countable levels. Enterobacteriaceae were found on one-third of the cleaned cutting boards. Cleaned work surfaces had the highest average TAC of all cleaned surfaces. Only slight improvements in TACs and Enterobacteriaceae and B. cereus counts were observed between used and cleaned work surfaces. The results from the data collection instrument revealed that child care centers had the lowest hygiene scores, whereas the other three sectors were fairly similar, with hospitals scoring highest. The low hygiene score for the child care centers was verified by comparing the results for cleaned surfaces among the sectors. The average TAC on surfaces was highest for child care centers and lowest for hospitals. Child care centers also had the second highest total mean counts and the highest number of total surface samples positive for Enterobacteriaceae. The highest number of surface samples positive for Staphylococcus aureus was also found in child care centers. This study highlights some areas of concern for hygiene improvement in institutional kitchens, differences between public sectors, and similarities in conclusions about hygiene based on the scores from the survey instrument and the results of the microbiological analyses.