Purpose: This study compares the transmission of coliforms and aerobic bacteria during beef slaughter in small and very small USDA-certified slaughter plants. This study is intended to provide small processors with a better understanding of intervention strategies, their effectiveness and the implications of inadequate interventions on foodborne outbreaks.
Methods: Unit operations (21 steps) in the slaughter process were identified for carcass, equipment and worker swabs. A total of 126 swabs were collected from each plant and samples were transported and analyzed on TSA and VRBA for enumeration within 24 h. All samples were incubated at 37°C for 18 - 24 h prior to enumerations.
Results: Data suggests that each unit operation from slaughter to fabrication of the beef carcasses reduced (P < 0.05) aerobic plate counts, total coliforms including E. coli. Comparison of a USDA-certified plant and a small processor indicate that there is a higher (P < 0.05) prevalence of coliforms and aerobic bacteria in the USDA-certified plant. Both slaughter plants demonstrated negative results during enumeration on VRBA in end product sampling, indicating the absence of coliforms. Microbial counts present after hide removal and prior to evisceration indicate transmission of bacteria via environmental factors, however, continued sampling is needed to clarify these correlations and the food safety gaps in beef slaughter.
Significance: The results of this study will be used to develop training modules for small processers and improve food safety in very small beef slaughter plants. Reducing foodborne illness will be achieved with continued open dialogue with small processers, strengthening extension and research efforts.