DETERMINING THE SURVIVAL CHARACTERISTICS OF SELECTED FOODBORNE PATHOGEN STRAINS IN MANURE-AMENDED AGRICULTURAL SOILS

Produce continues to be linked to foodborne outbreaks since many fruits and vegetables are consumed raw without a processing step that could inactivate microorganisms (2). Over a 15-year period beginning in 1990, produce was linked to 713 outbreaks and 34,049 cases of foodborne illnesses (3). Most recently in the US, outbreaks related to Escherichia coli O157:H7, O145, O26, Salmonella serovars, and Listeria monocytogenes have been linked to tomatoes, peppers, cantaloupe, mangoes, cucumbers, spinach, lettuce, and sprouts (4-19).The Food Safety Modernization Act (FSMA; which incorporates seven different food safety rules) was passed by Congress and signed into law by president Obama in 2011. FSMA emphasizes a preventive approach to food safety rather than responding and reacting to outbreaks (or contamination events). One of the seven rules in FSMA, the Produce Safety Rule (PSR), regulates the standards for the growing, harvesting, packing and holding of produce for human consumption (20). As of November 27, 2015, the final Produce Safety Rule was published in the federal registrar and provides standards for agricultural water, biological soil amendments, sprouts, worker health and hygiene, domestic and wild animals, equipment, building and tools, and other areas. In the final rule, the Food and Drug Administration (FDA) deferred action on the appropriate time interval or intervals between the application of untreated biological soil amendments of animal origin (including raw manure) and crop harvesting. While GAPs are voluntary, FSMA PSR compliance will be mandatory for many (as outlined by their size and profits, 20). Thus, the purpose of this project is to determine the survival characteristics of selected foodborne pathogen strains, specifically Salmonella spp. (12 strains), Escherichia coli (E. coli) O157 (8 strains), and non-O157 Shiga toxin-producing E. coli (STEC) (7 strains) in raw manure-amended agricultural soils. We will use raw poultry manure to study the survival of Salmonella and we will use raw cattle manure for the study of E. coli O157 and non-O157 STEC. The raw biological soil amendment and pathogen pair was selected, as prior studies have shown those biological soil amendments may contain the respected pathogen (25, 26). Additionally, the project will evaluate the survival of these pathogens in two different soil types commonly found on the Delmarva Peninsula (sandy-loam) and mainland Virginia (clay-loam) (37). The data will also be used to develop models for use of raw manure in agricultural settings and provide recommendations (to growers, produce industry) for their application to fields where produce will be grown. Specific objectives include:Salmonella survival "strain variability" (12 strains) in two types of soil (sandy and clay) with simulated soil moistureE. coli O157 survival "strain variability" (8 strains) in two types of soil (sandy and clay) with simulated soil moistureNon-O157 STEC survival "strain variability" (7 strains) in two types of soil (sandy and clay) with simulated soil moistureDevelopment of models to provide guidance on factors that influence the likelihood of pathogen survival in manure-amended soils