Risk assessment of Escherichia coli O157:H7 along the farm-to-fork fresh-cut romaine lettuce supply chain
This study models E. coli O157:H7 contamination in romaine lettuce from farm to fork, finding that contaminated irrigation water, especially from overhead spray systems, is the biggest pre-harvest risk factor. While less frequent, wildlife intrusions, runoff, and contaminated soil amendments also contribute to pre-harvest contamination, with time-temperature abuse during postharvest handling exacerbating the risk.