Survival of E. Coli on Soil Amendments and Irrigation Water in Leafy Green Field Environments

Fresh market leafy green vegetables periodically are subject to contamination from foodborne human pathogens such as E. coli. Field aspects of such contamination are not well understood, and there is a lack of information on where and how E. coli comes in contact with leafy greens in the field, how E. coli survives there, and how production factors influence this pathogen. It is notable that few in-field projects have been conducted to address such issues as they pertain to commercial environments for leafy greens in California.
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Our plan is to continue to develop field-generated information on the survival of E. coli under actual production environments for coastal California leafy greens. We will validate our initial findings regarding survival of generic and non-toxigenic O157:H7 strains of E. coli when introduced to irrigation water, soil, and plants of a spinach field. With this simulation of a contamination event in spinach, we document survival of E. coli under field conditions; such information will be useful in further improving metrics and regulatory measures.
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We will evaluate survival of generic and non-toxigenic O157:H7 strains when introduced as contaminants in fertilizer inputs (compost, amendments, teas or other extracts) that are subject to soil cultivation and other practices.