Summary of Awards to Date

Investigation of risk criteria and foodborne pathogen reduction practices for irrigation water

Date

Jan. 1, 2015 - Dec. 31, 2015

Funding Agency

Virginia Polytechnic Institute and State University

Amount Awarded

$152,344.00

Investigator

Steven Rideout, Ph.D.
Virginia Polytechnic Institute and State University

Co-Investigator(s)

Renee Boyer, Ph.D., Virginia Tech

Summary

Irrigation water is considered to be one of the main contamination sources of foodborne pathogens on produce.  Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes are three common enteric pathogens that may exist in irrigation water and are reported to be associated with produce contamination. Science-based data are needed to generate practical and accurate prediction methods and to establish effective strategies about decontamination of irrigation water to improve produce food safety. The purpose of this research project is to 1) Investigate practical criteria for the prediction of foodborne pathogens in irrigation pond and well water; 2) Evaluate the efficacy of commercial sanitizers on the decontamination of three common foodborne pathogens, Salmonella spp., E. coli O157:H7, and L. monocytogenes, in irrigation well and pond water; and 3) Provide education and training to stakeholders on improved agricultural practices to reduce the food safety risks in irrigation water. The outcomes of this research will benefit stakeholders especially vegetable and fruit industries to reduce the contamination risks of foodborne pathogens during irrigation and achieve the new requirements of FSMA on produce safety.

Technical Abstract

Current outbreaks of foodborne illnesses associated with vegetables and fruits attract more concerns about produce safety; irrigation water is considered to be one of the main contamination sources of foodborne pathogens on fresh produce. Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes are three common enteric pathogens that may exist in irrigation water and are reported to be associated with produce contamination. Science-based data are needed to generate practical and accurate prediction methods as well as effective decontamination strategies for irrigation water to mitigate contamination of produce by human pathogens at the production level. We propose to achieve research goals by fulfilling the following objectives:

  1. Investigate practical criteria for the prediction of foodborne pathogens in irrigation pond and well water. The spatial and temporal occurrence/population of foodborne pathogens, Salmonella spp., E. coli O157:H7, and L. monocytogenes, in irrigation pond and well water from four farms on the Eastern Shore of Virginia will be monitored and correlation to environmental parameters (temperature, rainfall, flood events, pH, dissolved oxygen, conductivity, and oxidation reduction potential), fecal indicator assessments (population of generic E. coli and fecal coliforms), diversity of bacterial communities, and presence or population of specific bacterial species will be assessed.
  2. Evaluate the efficacy of commercial sanitizers on the decontamination of three common foodborne pathogens, Salmonella spp., E. coli O157:H7, and L. monocytogenes, in irrigation well and pond water. The effects of four sanitizers, Clorox® Regular-Bleach, CDG Solution 3000™, Sanidate 5.0, and Sanidate 12.0 will be tested. Population reduction of foodborne pathogens will be compared after sanitizer treatments. Impacts of bacterial initial concentration levels (population densities of 8 log, 6 log, or 4 log CFU/ml), irrigation water sources (well or pond waters from four farms), water parameters (temperature, pH, dissolved oxygen, conductivity, and oxidation reduction potential), and bacterial communities including population of generic E. coli and fecal coliforms, on the reduction and available active ingredients of tested sanitizers will be also analyzed.
  3. Provide education and training to stakeholders on improved agricultural practices to reduce the food safety risks in irrigation water. Practices to mitigate food safety risks in irrigation water will be shared with stakeholders.

This study will evaluate the efficacy of physicochemical indicators and biological index organisms on the prediction of foodborne pathogen contamination in irrigation pond and well water. Analysis of the relationship between bacterial species and foodborne pathogens will improve current prediction and prevention strategies. Economical and efficient decontamination methods for irrigation water treatment will also be investigated based on the results of proposed study and shared with vegetable and fruit producers and other stakeholders. The outcomes of this research will benefit stakeholders especially vegetable and fruit industries to reduce the contamination risks of foodborne pathogens during the production and achieve the new requirements of FSMA on produce safety.