Evaluation of The Prevalence and Persistence of Shiga Toxin-producing E. Coli (stec) On Organic Mixed Crop-livestock Farms That Integrate Sheep Grazing Within Vegetable Fields

The overall aim of this study is to assess the prevalence and persistence of STEC in sheep and in soil within small to medium-sized farm environments, so that farmers can address on-farm food safety issues involved with grazing production field. The objectives include: 1) To determine the baseline prevalence of STEC in sheep in bio-diversified California farms; 2) To assess the persistence and concentration of generic E. coli, total coliforms and STEC in the soil (from Day 0 to harvest); 3) To analyze factors that may affect E. coli persistence; 4) To identify good agricultural practices (GAP) that prevent cross-contamination.