Tracking the Sources of Contamination and Evaluating the Effect of Cooking on Bacterial Load in Meat Meals Prepared and Served in Foodservice Establishments

Abstract

In this study, we determined the aerobic plate count, Staphylococcus (Staph.) aureus count, and most probable numbers (MPN) of coliforms, fecal coliforms, and Escherichia (E.) coli, and the presence of Listeria monocytogenes in 120 samples of beef steak and beef burger at various stages of preparation in a randomly selected food serving establishment in Beni-Suef City, Egypt. Additionally, 60 swab samples from knives, cutting boards, and operator's hands were investigated for the same bacteriological criteria. Subsequently, bacterial isolates were subjected to molecular identification by investigating the presence of virulence and antibiotic resistance genes. The results showed that 100 % of meat product samples at various stages of preparation contained aerobic bacterial load and Staph. aureus. Conversely, E. coli and L. monocytogenes were undetectable in meat product samples. Interestingly, 13, 7, and 1 out of 20 swab samples from hands contained coliforms, fecal coliforms, and E. coli, respectively, while knives and cutting boards were free from fecal coliforms and E. coli. Furthermore, contamination with Staph. aureus was reported in 100 % of knives and hand swab samples and 50 % of cutting board swab samples. Furthermore, the only E. coli isolate from a worker's hand contained eaeA gene, but not Stx1 gene, which indicates that it is an enteropathogenic E. coli (EPEC) strain. Moreover, 6 and 5 Staph. aureus isolates from operator hands and beef steak after cooking had coa and mecA genes, respectively, which are responsible for plasma coagulation and methicillin resistance, respectively. To sum up, this food serving establishment does not apply proper food safety guidelines, practices inadequate cleaning and sanitizing and poor personal hygiene, accordingly, it should be faced with a high level of concern and consideration by the legal authorities.