QUANTITATIVE ANALYSIS OF VERTICAL TRANSLOCATION AND LATERAL CROSS-CONTAMINATION OF ESCHERICHIA COLI O157:H7 DURING MECHANICAL TENDERIZATION OF BEEF

Quantitative vertical translocation and lateral cross-contamination of Escherichia coli O157:H7 during mechanical tenderization of beef meat were investigated using a restaurant-style meat tenderizer, which was first used to tenderize a surface-inoculated sample, and then an additional four uninoculated samples. It was observed that the vertically translocated bacteria (in log(10) cfu/g) was directly proportional to the logarithm of the tenderization depth, with an average translocation coefficient of 3.14 +/- 0.66 log(10) cfu/g per log(10) 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 log(10) 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.