Prevalence of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella in two geographically distant commercial beef processing plants in the United States

For two large beef processing plants, one located in the southern United States (plant A) and one located in the northern United States (plant B), prevalence of Escherichia coli O157:H7, Listeria spp., Listeria monocytogenes, and Salmonella was determined for hide, carcass, and facility environmental samples over the course of 5 months. The prevalence of E. coli O157: H7 (68.1 versus 55.9%) and Salmonella (91.8 versus 50.3%) was higher (P, 0.05), and the prevalence of Listeria spp. (37.7 versus 75.5%) and L. monocytogenes (0.8 versus 18.7%) was lower (P, 0.05) for the hides of cattle slaughtered at plant A versus plant B. Similarly, the prevalence of Salmonella (52.0 versus 25.3%) was higher (P, 0.05) and the prevalence of Listeria spp. (12.0 versus 40.0%) and L. monocytogenes (1.3 versus 14.7%) was lower (P, 0.05) for the fence panels of the holding pens of plant A versus plant B. The prevalence of E. coli O157:H7 (3.1 versus 10.9%), Listeria spp. (4.5 versus 14.6%), and L. monocytogenes (0.0 versus 1.1%) was lower (P, 0.05) for preeviscerationcarcasses sampled at plant A versus plant B. Salmonella (both plants), Listeria spp. (plant B), and L. monocytogenes (plant B) were detected on fabrication oor conveyor belts (product contact surfaces) late during the production day. For plant B, 21 of 148 (14.2%) late-operational fabrication oor conveyor belt samples were L. monocytogenes positive. For plant B, E. coli O157:H7 and L. monocytogenes were detected in preoperational fabrication oor conveyor belt samples. Overall results suggest that there are regional differ