Quantitative analysis of vertical translocation and lateral cross-contamination of Escherichia coli O157:H7 during mechanical tenderization of beef

Authors: Huang, Lihan; Sheen, Shiowshuh - Allen

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2010
Publication Date: 2/1/2011
Citation: Huang, L., Sheen, S. 2011. Quantitative analysis of vertical translocation and lateral cross-contamination of Escherichia coli O157:H7 during mechanical tenderization of beef. Journal of Food Safety. 31:108-114.

Interpretive Summary: E. coli O157:H7 is a deadly pathogen that can cause major outbreaks of foodborne poisoning in the U.S. The outbreaks caused by this microorganism are primarily associated with ground beef, but mechanically tenderized beef steaks also can be contaminated. This study investigated the translocation and cross-contamination of E. coli O157:H7 during mechanical tenderization of subprimal beef meat. The results of this work can be used for risk assessment of mechanical tenderization of beef products and for the formulation of science-based food safety policies.

Technical Abstract: Quantitative vertical translocation and lateral cross-contamination of Escherichia coli O157:H7 during mechanical tenderization of beef meat was investigated using a restaurant-style meat tenderizer, which was first used to tenderize a surface-inoculated sample, and then additional 4 uninoculated samples. It was observed that the vertically translocated bacteria (in log10 cfu/g) was directly proportional to the logarithm of the tenderization depth, with an average translocation coefficient of -3.14 +/- 0.66 log10 cfu/g per log10 mm of depth. For lateral cross-contamination, the bacterial counts recovered from the top layers of the first four pieces of meat decreased by approximately 0.5 log10 cfu/g after each tenderization. There was no decrease in the bacterial counts recovered from the top layers after the 4th tenderization. More tenderization studies were needed to quantitatively analyze the trend of lateral cross-contamination. However, it is evident that both vertical translocation and lateral cross-contamination can occur during mechanical tenderization of meat.