A Randomized Study of Microbial Contamination in Ready-to-eat Beef in Shanghai, China

Abstract:

The bacterial contamination of ready-to-eat (RTE) beef products in Shanghai was investigated. Twenty RTE beef samples were randomly collected from five international supermarkets and five street vendors in Shanghai, China. The total number of bacterial colonies was measured using the culture method, and ten colonies from each sample were randomly selected for bacterial classification and identification by 16S rRNA gene sequencing. The average total colony counts of the beef samples collected from the supermarkets and street vendors were 1.08±1.73×108 CFU/g and 2.84±8.49×108 CFU/g, respectively; there was no statistically significant difference (p>0.05) between them, but both were higher than the national standard of China (≤8×104 CFU/g). Pathogens that could cause severe food poisoning were not detected in any sample, but several operational taxonomic units (OTUs) that were closely related to food poisoning, urinary tract infections, pneumonia, mastitis, and bacteremia were detected. The results suggest that RTE foods are an important but often overlooked reservoir for pathogenic microorganisms, and we should strengthen our hygienic practices and management of RTE foods to reduce the risk of food-borne disease caused by them.