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The main goals of this project focus on reducing the risk of bacterial pathogen contamination on leafy greens (LGs) and fresh market tomatoes from irrigation/spray water, aged manure and soil amendments, and insect and dust transmission of pathogens from nearby farm animal/compost operations.<P> The project objectives and approaches involve trans-disciplinary and multi-institutional academic, scientific, and extension experts who target the following specific priority objectives: <BR> To evaluate and compare the efficacy and appropriateness of on-farm treatments for surface water sources for crop irrigation and spray on the microbiological quality of harvested LGs and fresh market tomatoes; <BR>To evaluate stability as an indicator of the bacterial pathogen inhibition capacity of manure/compost soil amendments and compost tea feedstocks suitable for use in production of LGs; <BR>To evaluate the transport and fate of fecal indicator microorganisms, such as coliform bacteria, E. coli, and Salmonella, within a small-farm production environment by flying insects and dust to LGs and tomatoes in field plots and high tunnels; <BR> To to provide comprehensive outreach and technical training in Good Agricultural Practices for safe production of LGs and other fresh market produce to area produce growers and others. <P>Outputs: The project's outputs are: 1) the characterization of environmental, growing, and harvesting practices that are associated with bacterial contamination of fresh produce; 2) the development of protocols that ensure the safe production of fresh produce, leafy greens, and tomatoes; 3) the safe production of vegetable crops, i.e., spinach and tomatoes; 4) at least one conference proceeding, five refereed journal articles, six abstracts, three extension bulletins, two videos and CDs; and 5) four graduate and >15 undergraduate students trained in this technology. <P>Expected benefits are: 1) spinach and tomatoes free of pathogens; 2) enhanced crop productivity and quality; and 3) strengthened capacity at UMES, VSU, NC A&T and DSU for microbial and environmental studies and food safety. The potential impacts are: 1) a more profitable production of spinach; 2) enhanced sustainable agriculture; 3) the preservation of vegetable crops and environmental quality; 4) highly trained minorities and underrepresented students and young scientists, including females for the work force; and 5) research model technology adapted by other institutions, in particular 1890 institutions.
Non-Technical Summary: Reducing foodborne illnesses associated with fresh produce is a USDA-NIFA Food Safety strategic goal. Current, industrial-scale production, harvesting, and processing practices for LGs and tomatoes stipulate certain metrics and procedures that required scientific evaluation. They present potential major impediments for small-scale producers serving local communities. The proposed USDA-AMS national marketing agreement for LGs incorporates these industrial-scale metrics without regard to farm scale. Science-based, cost-effective measures are needed to eliminate/reduce field-borne food-safety risk pathogens from contacting/surviving on/in these two commodities without so severely impeding small-scale producers so that they are forced out of business. This project proposes a multi-institutional approach involving research, education, and extension. Need Area - To provide science-based evaluations for key elements of field production, food-safety metrics, and challenges confronting small-scale producers. Our food safety and water quality priority area project focuses on the use of a multi-disciplinary approach to accomplish four objectives: 1) to evaluate the efficacy of on-farm treatments for surface water sources for crop irrigation and spray on the microbiological quality of harvested LGs and tomatoes; 2) to evaluate stability measures for manure-based products used as soil amendments and feedstocks for compost tea with LGs; 3) to evaluate the transport/fate of E. coli and Salmonella to LGs and tomatoes by flying insects and dust within a small-farm; and 4) to provide outreach and technical training to produce growers and others in Good Agricultural Practices related to the safe production of fresh market produce. Expected impacts include the training of more than 20 students (four graduates) and enhanced 1890-institutional capacity in food safety of fresh produce. This project proposes a multi-institutional approach involving research, education, and extension Needs Areas to provide science-based evaluations for key elements of field production food-safety metrics challenges confronting small-scale producers. Our Food Safety and Water Quality priority areas project focuses on the use of a multi-disciplinary approach to accomplish four objectives: 1) Evaluate the efficacy of on-farm treatments for surface water sources for crop irrigation and spray on the microbiological quality of harvested leafy greens and tomatoes; 2) Evaluate stability measures for manure-based products used as soil amendments and feedstocks for compost tea with leafy greens; 3) Evaluate transport/fate of E. coli and Salmonella by flying insects and dust within a small-farm to leafy greens and tomatoes; 4) Provide outreach and technical training to produce growers and others in Good Agricultural Practices related to safe production of fresh market produce. Impacts expected include training of more than 20 students (4 graduates) and enhanced 1890-institutional capacity in food safety of fresh produce. <P> Approach: This project examines three aspects of fresh produce farming situations: 1) evaluation of the efficacy and appropriateness of various types of on-farm treatments for irrigation and spray water on LGs and tomatoes; 2) evaluation of the stability of soil amendments and the survival of E. coli O157:H7 and Salmonella in compost teas prepared from different types of soil amendments; and 3) evaluation of the impact of set-back distances and interventions between animal rearing, manure handling, composting operations, and LGs and tomato production relative to the transport of manure dust or insect vectoring from contaminated sources to crops. This project involves: 1) use of advanced molecular and microbial techniques to detect and quantify pathogens on crops, soil, manure/soil amendments, irrigation/spray water, and insects in fields and high tunnels; 2) specific provision for project quality control and assurance monitoring/reporting and microbial identification confirmations; and 3) verification of the efficacy and cost-benefits of on-site water treatment technologies for small-scale irrigation/spray water for LGs to prevent pathogenic bacterial contamination. Samples of tomatoes and lettuce, soil, animal/poultry manure/litter, insects, water, sediment, and compost will be assayed for the presence of fecal coliforms, generic E. coli, EHEC/STEC strains, and Salmonella. Fecal coliforms and generic E. coli will be detected. S. enterica and EHEC/STEC strain detection assays from fresh produce will conform to techniques described by the FDA, utilizing appropriate pre-enrichment and enrichment protocols adapted to a mini-most probable number method for enumeration of samples suspected to have low density populations. PCR of enriched samples will be used to confirm target microbe presence/absence when culture methods are inconclusive. Field and lab blanks and positive and negative quality controls will be used in each lab for each matrixmicrobe to document detection sensitivity and procedural quality. Produce samples will be assayed in a two-stage modification of the shake-rub-shake method to estimate populations of surface and internalized bacteria. Rinsates of whole fruit (tomatoes) or LGs will be obtained by immersing samples in sterile buffered peptone water in a stomacher bag and manually rubbing them from the outside of the bag 5 min, then sonicating them in a water bath for 15 sec. Buffered peptone water will be added to stomacher bags containing rinsed tomato or LG samples to achieve a 1:10 dilution, and then homogenized for 2 min. Rinsate and homogenate samples will be analyzed separately using standard and enrichment techniques. Aliquots (5-ml) of primary (1:10) dilutions of all samples will be transferred to sterile freezer vials (-80C) for future molecular genetic analysis for target fecal indicators and other. Bacterial colonies will be transferred to suitable culture media, incubated, and examined for confirmation of identity and genotyping. Individual pathogen isolates will be genotyped using pulsed-field gel electrophoresis (PFGE) analysis and compared to those from animal/compost sources to identify potential transmission vectors.