Edward Atwill

　　Western Institute for Food Safety and Security, School of Veterinary Medicine, University of California, Davis,

　　Zoonotic pathogens present in the feces and urine of wild and domestic animals have a long history of causing human enteric disease through consumption of contaminated foods of animal origin, occupational exposure, and inadequately treated drinking water. More recently, there is a growing realization that many fruits, vegetables, and nuts that are consumed raw or after minimal processing are vulnerable to pathogen contamination.

　　There are several scenarios that could allow animal waste to contaminate produce: (1) improperly processed animal composts used as soil amendment, (2) irrigation water that is contaminated with microbial pathogens from animal waste, and (3) direct defecation of domestic animals and wildlife into the produce field. Regarding composts, there is a continuing need to diversify cost-effective technologies for liquid and solid manure management systems common to intensified animal agriculture. Cost-effective methods to protect and insure the microbiological quality of irrigation water remain poorly developed for many regions of the world. Numerous management techniques have been developed to safeguard surface irrigation supplies from fecal contamination of extensive livestock populations. Lastly, recent food-borne outbreaks traced to human consumption of raw fruits and vegetables exposed to wildlife feces highlight the need for new biosecurity protocols that prevent animal defecation into fields of produce. These issues are a few examples of the many challenges still facing the public health community in the area of produce food safety, wildlife biodiversity and irrigation water quality.