Irrigation Regime, Fruit Water Congestion and Produce Safety: Parameter Optimization to Reduce Susceptibility of Tomatoes and Peppers to Post-Harvest Contamination, Pathogen Transfer and Proliferation of Salmonella

Recent multi-state outbreaks of vegetable-borne gastrointestinal illnesses demonstrate that
human pathogens can contaminate produce at any stage of production. The fact that the
outbreaks have been sporadic and the uncertainty regarding sources and routes of
contamination argue for the possibility that some event(s) during the production cycle make
vegetables more susceptible to contamination from environmental sources of pathogens. <P>
We
hypothesize that irrigation-determined physical properties of tomatoes and peppers (fruit
wetness, fruit water congestion, etc) may make them more vulnerable to contamination from
various environmental sources, including transfer from rubber gloves or wiping cloths. Fruit
wetness and fruit water congestion also increase susceptibility of vegetables to plant
pathogens, and the association with plant pathogens has been well-documented to promote
growth of Salmonella in vegetables.<P>
The overall goal of this project is to test how irrigation determined
physical properties of tomatoes and peppers affect vulnerability of produce to
infections by Salmonella.<P>
Upon completion of this project, we expect to have defined an
optimal irrigation regime under which yields are maintained, yet the vulnerability of produce to
contamination and proliferation of Salmonella are reduced. Following a successful completion
of the first two production seasons, a full scale on-farm demonstration will be carried out.