Conservation Practices and Food Safety in California.

Outbreaks of foodborne illness associated with the consumption of leafy green produce have heightened concerns in California about the potential role that wild vertebrates and irrigation water have in contaminating produce with microbial pathogens. In particular, concern has focused on wildlife species that have direct access to the produce production environment and surface irrigation water supplies that are either exposed to fecal contamination and/or reused as can occur with tail-water recovery systems or sediment basins. In the absence of scientific data, the default response by many growers under heavy regulatory and legal pressure has been to minimize all perceived sources of microbial risk. This can result in widespread trapping and removal of wildlife from the production environment, elimination of wildlife and riparian habitat in proximity to production fields, biosecurity measures for pre-irrigation reservoirs, and discouragement of reusing irrigation water even during a drought year due to the perceived risk of elevated bacterial concentrations in reused water sources. This presentation will present information regarding the comparative food safety risks of wildlife intrusion into fields of produce and the potential role of pre-irrigation reservoirs, foliar irrigation systems and reuse of irrigation water on microbial contamination of leafy green produce. For example, many wildlife species forage as a group directly in fields of produce leading to in-field defecation, which substantially elevates the risk of microbial contamination compared to larger animal species that do not have direct access to produce fields due to fencing. Foliar applied irrigation is capable of creating soil and fecal splash from the furrow onto nearby produce, substantially elevating the food safety risk. Drip irrigation systems avoid this erosive process and have other obvious water conservation benefits. Ultimately, our society will need to weight the potential health risks against the agricultural and environmental benefits of maintaining various conservation practices in leafy green production systems and come to consensus on the design of good agricultural practices that achieve healthy food, sustainable agriculture, and environmental conservation.