Jul. 1, 2013 - Jun. 30, 2014Amount Awarded
Faith Critzer, Ph.D.
University of Tennessee
Water used for frost protection and irrigation is one of the most likely points of pathogen contamination during fruit and vegetable production. Previous studies have focused on chemical rather than microbiological water-‐quality parameters. Consequently, a knowledge gap exists regarding surface water sanitary quality and the risks associated with the timing and method of application. In response to FDA’s proposed standards for surface water quality, we propose to evaluate the transfer and survival of organisms of public health concern (Shiga Toxigenic E. coli [STEC]) as well as indicator microorganisms (E. coli and fecal coliforms) in the field using cantaloupe as a model crop. A pond, accessed by cattle and with populations of all organisms of interest, will be utilized as the irrigation source for this study. Both drip and spray irrigation methods will be evaluated on bare-‐ground as well as plasticulture systems.
There is currently a need to understand the transfer and survival of foodborne pathogens as well as indicator organisms from surface water that is naturally contaminated with foodborne pathogens as well as high microbial loads of generic Escherichia coli and fecal coliforms. This project team will establish plasticulture and bare-‐ground research plots with cantaloupe as the model crop, and compare irrigation regimes from a pond that also serves to water beef cattle, with high populations of fecal coliforms, generic E. coli as well as the presence of Shiga Toxigenic E. coli (STEC).
During irrigation, water will pass through a sand filter and then be divided across two irrigation delivery systems (drip and overhead). Water samples will be taken from the pond and from the irrigation discharge to evaluate target organism populations. The team’s research will determine the transfer of STEC, E. coli, and fecal coliforms and survival of these organisms on cantaloupe. Fruit will be sampled during early, peak, and late harvest. Cantaloupe will provide a warm season model crop and will demonstrate differences in potential pathogen contamination between drip and overhead irrigation, as well as bare-‐ground and plasticulture systems. Yield and quality will also be compared to evaluate treatment impacts.
This research will act as a precursor to a complimentary proposal submitted by this team to the Center for Produce Safety. If funded, this work would allow our team to begin site setup and troubleshoot any issues with methodology prior to work beginning on the CPS project. In addition, this research will allow us to leverage an additional season of transfer and survival data for cantaloupe and untreated surface irrigation water.