A systems approach to determine the fate of Escherichia coli O157:H7 on fresh and fresh-cut iceberg lettuce and spinach
Doering, Helga J.
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The systems approach was used to determine the fate of Escherichia coli O157:H7 on iceberg lettuce and spinach under conditions that mimic those from field to finished bagged product. Spinach and lettuce were inoculated with E. coli O157:H7 and processed and held under conditions typical of those in the fresh or fresh-cut produce industry (washed in chlorine water, packaged, and held to mimic retail distribution). Results showed immediately cooling (p < 0.0001), washing in chlorine water (p < 0.0001), and continually practice of the cold chain (p < 0.0001) led to lower populations of E. coli O157:H7 and background microflora. At 4°C storage the E. coli O157:H7 populations decreased by at least 1.5 logs in retail bags over time up to 18 days. Longer times before cooling down and higher temperatures increased E. coli O157:H7 and background microflora populations over time. In retail bags, stored at higher temperature (25 or 32°C), microbial populations increased rapidly and the product quality quickly declined.