Microbiological contamination of raw beef trimmings and ground beef

Abstract

To survey the microbiological quality of beef trimmings and final-ground beef, samples were collected from eight commercial grinding facilities, including trimmings from fed-cattle, culled-beef cows, culled-dairy cows, imported-beef trimmings and finished-ground products. Trim samples (core and purge) and ground product samples (n=586) were evaluated for aerobic plate (APC), total coliform (TCC), Escherichia coli (ECC) and Staphylococcus aureus counts and the presence of Salmonella spp. and Listeria monocytogenes. As fat content in the trimmings increased, APC also increased. Trimmings from fed-cattle had higher (P<0.05) APC and TCC than trimmings from culled-beef cows, culled-dairy cows and imported trimmings. Purge samples produced higher (P<0.05) APC, TCC and ECC than core samples, but there were no difference (P>0.05) across fat percentages in APC, TCC, ECC or S. aureus counts. Final-ground beef samples had a 13.6 and 1.5 % incidence of L. monocytogenes and Salmonella spp., respectively. The results of this study indicate specific areas of potential that ground beef processors could capitalize upon to further improve the microbiological quality of their finished product. Ground beef processors should focus their efforts on reducing the microbial counts on incoming raw materials, especially those containing large proportions of subcutaneous fat, and processors should no longer incorporate the purge component of raw materials into ground beef. From this study, it is also apparent that ground beef processors should implement sanitation and manufacturing procedures that address L. monocytogenes contamination.