Organic Soil Amendments and Food Safety for Fresh Organic Produce.

Use of raw, composted, aged, or treated animal manure, or other organic residuals is integral to many organic cropping systems, including those that produce fresh fruits and vegetables. Although application of organic soil amendments is a well-documented approach to enhance soil productivity, it can pose a potential food safety risk from pathogenic microorganisms that survive and contact fresh produce grown on manure-amended soils. During the past decade, outbreaks of human gastroenteritis, complicating illnesses, and deaths have been associated with consumption of fresh produce, particularly leafy greens (including herbs), cantaloupes, tomatoes, peppers, green onions, and berries contaminated with pathogens usually considered to have originated from fecal sources. Various produce grower groups and commercial buyers, as well as state, federal, and international agencies have responded by establishing recommendations for pre- and post-harvest handling of fresh fruits and vegetables. Increasingly these groups are requiring on-farm audits to ensure fresh produce is grown and handled using best available practices to avoid contamination by zoonotic pathogens. The U.S. Food and Drug Administration's new regulations authorized by Congress in the Food Modernization Act of 2011 are expected to deal with use of organic soil amendments. Research results on manure pathogen survival in pre- and post-harvest conditions in organic production of leafy greens will be presented. The influence of manure and bacterial types and concentrations on survival and persistence of pathogenic bacteria in conventional and organic systems will be discussed.