Isolation of Escherichia coli from lymph nodes of bovine carcasses and detection of hlyA gene with PCR

A potential source of pathogenic bacteria in ground beef is the lymphatic system, specifically the lymph nodes. The objective of the current study was to determine the prevalence of Escherichia coli in bovine lymph nodes. Bovine lymph nodes (n = 200) were collected from 100 carcasses at a commercial slaugh-terhouse. 192 lymph nodes sampled were obtained from 96 regular slaughter, and the remainder 8 were obtained from 4 emergency slaughter. Subiliaci lymph nodes were collected for this study. E. coli preva-lence in the lymph node samples was high, with an overall prevalence of 59.00%. Lymph nodes from emergency slaughter carcasses had a higher prevalence (75.00%) of E. coli than did those from regular slaughter carcasses (58.33%). hlyA gene was never detected.