Assessment of organic produce farming research and outreach needs regarding food safety risks, raw manure and compost applications

Authors: DE MELO RAMOS, THAIS - University Of California, Davis; JAY-RUSSELL, MICHELE - University Of California, Davis; Millner, Patricia; SHADE, JESSICA - The Organic Center; MISIEWICZ, TRACY - The Organic Center; SORGE, ULRIKE - University Of Minnesota; HUTCHINSON, MARK - University Of Maine Cooperative Extension; LILLEY, JASON - University Of Maine Cooperative Extension; PIRES, ALDA - University Of California, Davis

Submitted to: Frontiers in Sustainable Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2019
Publication Date: 9/6/2019
Citation: De Melo Ramos, T., Jay-Russell, M., Millner, P.D., Shade, J., Misiewicz, T., Sorge, U., Hutchinson, M., Lilley, J., Pires, A.F. 2019. Assessment of organic produce farming research and outreach needs regarding food safety risks, raw manure and compost applications. Frontiers in Sustainable Food Systems. 3:73. https://doi.org/10.3389/fsufs.2019.00073.
DOI: https://doi.org/10.3389/fsufs.2019.00073

Interpretive Summary: Use of biological soil amendments of animal origin (BSAAOs) to maintain soil health and provide crop nutrients is an especially important practice used by organic farmers who are certified by the USDA’s National Organic Program (NOP), because use of synthetic chemical fertilizers on these organic farms is prohibited. However, application of untreated or partially composted animal manure (“raw manure”) to soil may provide a pathway by which foodborne illness pathogens, including E. coli O157:H7, Salmonella spp., Campylobacter spp., Listeria and Cryptosporidium parvum, could contaminate fresh produce, either by splash, wind, or direct contact with the amended soil. For produce typically consumed raw (without cooking), such contamination is a food safety hazard. This study was conducted to determine knowledge, attitudes, behaviors, and practices of organic farmers about the use of BSAAOs, including rotational grazing and composting, in organic and sustainable agriculture with a focus on fresh produce (e.g., vegetables, nuts and fruits) commodities covered under the USA, Produce Safety Rule. Three evaluation tools were implemented to gather data: 1) a national workshop held at the University of California-Davis (UC Davis); 2) multiple in-person focus group (listening) sessions conducted at locations across the United States; and an online survey. This study revealed a consensus among all of the audiences that there is a need for more science-based data on the time-interval dynamics as related to soil quality conditions and their association with survival and transfer of foodborne pathogens from soils amended with raw manure to organic fresh produce. This study highlights the continued need to strenghten outreach and educational tools to help producers implement mitigation strategies to reduce food safety risks related to use of raw or partially composted manure in organically-grown produce. This study will inform and aid prioritization of research and outreach programs aimed at improving food safety for organic vegetable, fruit, and nut growers who use untreated animal-based soil inputs, including amendments and rotational grazing.

Technical Abstract: The use of biological soil amendments of animal origin (BSAAOs) to improve soil fertility and quality, plays an important role in organic agriculture in the U.S. However, use of untreated manure application may introduce foodborne pathogens and consequently increase the risk of fresh produce contamination. Certified organic farms follow the USDA-National Organic Program (NOP) standards, which stipulate a 90- or 120-day waiting period between incorporating raw manure into the soil and crop harvest, depending on whether the edible portions of the crops come into indirect or direct contact, respectively, with the soil. To determine knowledge, attitudes, behaviors, and practices of organic farmers related to use of biological soil amendments, we employed three evaluation tools: a national workshop held at the University of California-Davis (UC Davis); multiple in-person focus group (listening) sessions conducted at multiple locations across the United States; and an online survey. Results reveal that all of the audiences were unanimous regarding the need for more science-based data time-interval dynamics associated with the survival of foodborne pathogens in soil amended with untreated animal-biological amendments in from contaminating organic fresh produce systems. This study highlights the need for development of outreach and educational tools intended to help producers implementing mitigation strategies to reduce food safety risks related to BSAAOs in organically-grown produce covered by the Produce Safety Rule. This study informs and will aid prioritization of research and particularly outreach programs aimed at improving food safety strategies and practices for organic vegetable, fruit, and nut growers who use untreated animal-based soil inputs, including amendments and rotational grazing.