Project Summary

Microbial Mapping II. Determining Microbiological Counts on Beef Carcasses, Wholesale Cuts and Retail Cuts, to Assist Those in the Fabrication, Distribution and Retailing Sectors to Deliver Safe Beef to Retail Customers

Principle Investigator(s):
J.N. Sofos, M. L. Kain, K. E. Belk and G. C. Smith
Colorado State University
Completion Date:
February 1999


Layman’s Summary 

Previous research has demonstrated that beef packers have invested enormous time and resources, and are generally succeeding, in efforts to decrease the presence of pathogens on carcasses. While several factors, such as handling, fabrication, packaging and distribution of beef products can cause further contamination, it is important to find out where the potential contamination is most likely to occur. This study evaluated the microbial profile of beef carcasses, wholesale cuts and retail cuts as they moved through the beef chain. 

A total of six slaughter/dressing facilities were evaluated across the United States. Beef cuts from the various sectors were evaluated for aerobic plate count (APC), total coliform count (TCC), generic Escherichia coli (ECC) and the presence/absence of Salmonella and Listeria monocytogenes. Retail cuts were also evaluated for Staphylococcus aureuscounts (SAC). 

There were differences in microbial counts between plants and cut type. The subprimals (wholesale cuts) sampled at retail stores had higher counts than the subprimals sampled at the plant for APC, however, the subprimals at retail had lower TCC and ECC than those cuts sampled at the plant, indicating that handling conditions and temperature were under control during transportation and distribution. The low recovery of SAC on retail products indicates some, but low, product contamination from retail employees. The low recovery of ECC at all stages of the process indicates minimal fecal/ingesta contamination of the carcasses and subprimals. Salmonella incidences were also very low for all cuts sampled. However, there is a concern regarding the level of Listeria monocytogenes contamination that occurred at the fabrication and retail stages of beef distribution.