Safe Produce Production Using Manure

Fresh produce associated cases of food borne illness reported annually in the United States has doubled during the past two decades. Contamination of produce during pre-harvest production can occur from several sources: raw manure, improperly composted or treated manure, or contaminated soil and/or water. The objectives of this project are to identify technologies and conditions that reduce pathogen populations in manure and to determine the fate of pathogens on vegetables grown in manure-amended soils. The effectiveness of three manure treatment technologies (composting, alkaline stabilization, and soldier fly maggot digestion) to reduce pathogens in raw manure (chicken and bovine) will be compared. Pathogens to be studied include: E. cold 0157:H7, Enterococcus faecium/fecalis, Salmonella spp., and Listeria monocytogenes. In addition, the fate of these pathogens relative to the harvestable commodity when the raw or treated manures are applied to soil for growth of selected vegetables will be quantified. Pathogen content and survival in compost and manure "tea" and on harvestable, market-ready plant parts sprayed with such "tea" will also be evaluated. There will be three phases to the project:Phase 1: Efficacy of treatment technologies and corresponding conditions to inactivate in manure. Phase II: Fate of pathogens in soil and on vegetables that are grown in environmental chambers under simulated field environment conditions for vegetable production. Phase III: Fate of avirulent Salmonella spp. and L. innocua, under field conditions in which vegetables are grown where manure fertilization and irrigation water are the sources of Listeria and Salmonella contamination.