Quantitative Risk Assessment for Escherichia coli O157:H7 in Fresh-cut Lettuce

Abstract

A farm-to-fork quantitative microbial risk assessment (QMRA) model was developed to estimate the risk of illnesses associated with <italic>Escherichia coli </italic> O157:H7 in fresh-cut lettuce, and to evaluate the effects of potential intervention strategies on reducing public health risks. Assuming a prevalence of 0.1% of lettuce entering the processing plant, the baseline model reflecting current industry practices predicted an average of 2,160 cases per year in the United States. For each of the additional intervention strategies evaluated, health risks were reduced by 11- to 18-fold. Treatment with ultrasound and organic acid combination was the most effective, reducing the mean number of cases by approximately 18-fold compared to baseline model. The developed risk model can be used to estimate the public health risk of<italic>E. coli</italic> O157:H7 from fresh-cut lettuce and to evaluate different potential intervention strategies to mitigate such risk.