Purpose: The purpose of this study was to quantify the relative impact of cross-contamination from the cutting and conveyor equipment surface in slaughter house on E. coli O157:H7 contamination on end beef products and subsequent health risks associated with its consumption.
Methods: A QMRA model was developed to evaluate the public health risk associated with consumption of ground beef and other beef products. Three potential contamination sources were evaluated and compared, including hides, gut and cross-contamination. The concentration of E. coli O157: H7 were then incorporated into a dose-response model, to estimate and compare the public health risks associated with the consumption of different beef products. Attributable risks to the evaluated potential contamination sources were evaluated as well.
Results: When all the contamination sources were considered, the model predicted the mean probability of illness associated with consumption of ground beef to be 6.3 × 10-4 with a 95% C.I. (1.25 × 10-5 - 8.9 × 10-2). When cross-contamination was not modelled, the mean probability of illness associated with consumption of ground beef was calculated as 3.9 × 10-4 with a 95% C.I. (1.9 × 10-6 - 1.6 × 10-2), indicating 38.1% of the ground beef relevant E. coli O157: H7 infections can be attributable to the cross-contamination in processing plant.
Significance: The findings suggest that relative risks of E. coli O157:H7 infection associated with consumption of beef products could be significantly higher as a result of cross-contamination from cutting & conveyor equipment surface.