Assessment of current practices of organic farmers regarding biological soil amendments of animal origin in a multi-regional U.S. study

Certified organic producers use biological soil amendments of animal origin (BSAAOs) to improve soil fertility and quality. Criteria for prevention of microbial contamination of crops have been based on the time interval between the application and crop harvesting. The objective of this study was to assess current practices related to the use of BSAAOs and food safety risks in organic agriculture, with a focus on produce commodities covered under the Produce Safety Rule. A total of 666 producers com-pleted the survey (571 online and 95 hardcopy); 89.2% (594/666) of the respondents produced fresh produce. Eighty-two percent of the producers were certified organic and represent relatively small-to medium-size farms. BSA-AOs were applied by 46.8% of producers growing produce that is typically consumed fresh. Fifty-eight percent of the farmers reported the use of raw manure. This survey showed that multiple factors related to on-farm manure management practices, which may directly affect survival and persistence of pathogens in manure-amended soils, vary by region and by state in the U.S. Thus, mitigation practices to decrease the risk of potential microbial contamination to fresh produce resulting from application of untreated manure must take into account multiple factors across different regions. This survey provides a framework for risk mitigation strategies to reduce microbial contamination of fresh produce in systems using BSAAOs, mainly untreated manure, in organic agriculture.