Effects of Antimicrobial Interventions on Indicator Organisms during Beef Carcass Dressing

Beef slaughter establishments employ many interventions to help minimize the occurrence of pathogens in their products. This study explored the effectiveness of various common interventions on microbial load using the results of the Beef-Veal Carcass Baseline Survey conducted in 2014 to 2015. The Food Safety and Inspection Service analyzed swab samples taken from 1,135 carcasses at 139 establishments. These included paired samples from post-hide removal (before evisceration) and prechill (after evisceration). Samples were tested for pathogens (Salmonella and Shiga toxin-producing Escherichia coli) and indicators (E. coli, Enterobacteriaceae, coliforms, and aerobic count [AC]). The sample size for pathogen-positive samples was small, impeding the establishment of a direct correlation between interventions and pathogens. However, we observed associations between pathogen-positive rate and log AC, indicating similar intervention effectiveness of pathogens and indicators in this study. Generally, the use of interventions reduced indicator concentrations. Each intervention produced a range of effectiveness, suggesting that how interventions are applied may be as important as which interventions are applied. The range of effectiveness for single interventions was a 0.4- to 1.9-log AC reduction; for multihurdle interventions, it ranged from 1.6- to 2.9-log AC reduction. The results of this study may be used by slaughter establishments to help identify effective intervention options for pathogen reduction.