#02-140

Complete

Date Full Report Received

01/11/2003

Date Abstract Report Received

12/19/2006

Investigation

Institution:
Primary Investigator:

Previous laboratory studies have demonstrated that snap/blast chilling is known to significantly reduce some bacterial populations on pork surfaces, including Salmonella, Campylobacter, E. coli, and coliforms. However, very little information exists as to whether reductions observed under commercial conditions can be attributed to chilling parameters. In this study, individual carcass sponge samples from 386 carcasses were obtained; 188 samples from warm carcasses and 198 samples from chilled carcasses. Chilled carcasses were subjected to snap/blast chilling (followed by conventional chilling) or conventional chilling and evaluated for mesophilic aerobic plate counts (APC), generic E. coli (EC), coliforms (CF), as well as the presence/absence of Salmonella spp., Campylobacter spp., and Listeria monocytogenes. Carcass samples were obtained from one very small, three small, and three large pork processing establishments. Of these, three establishments used conventional chilling only and four establishments used snap/blast chilling, followed by conventional chilling. Overall, warm carcasses sampled with the USDA three-site sampling procedure exhibited approximately 10 million APC, 85 EC, and 170 CF in a 300 square cm area. Salmonella spp., L. monocytogenes, and Campylobacter spp. also were present on 2.1%, 1.2%, and 7.4% of the warm carcasses, respectively. Chilled carcasses exhibited approximately 160,000 APC, 2 EC, and 3 CF in a 300 square cm area. Pathogen prevalence on the chilled carcasses was 4.3% Salmonella spp., 0.05% L. monocytogenes, and 0.0% Campylobacter spp. In addition to microbial populations, chilling parameters, and carcass surface temperature data were collected. Based on these findings, the use of snap/blast- or conventional chilling processes that reduce pathogenic bacteria may provide processors with an additional means to control pathogens in/on freshly slaughtered pork, thereby improving the microbiological safety of pork products.