EAST LANSING, Mich. — Compost can greatly contribute to overall plant and soil health, adding beneficial bacteria and fungi as well as providing organic material and available nutrients. From a food safety perspective, improperly prepared compost from animal manure, animal mortality or post-consumer food residue used in growing fresh produce may be risky. Proper storage of composted animal derived materials is essential to ensure a reduced risk of contamination. The Produce Safety Rule as part of the Food Safety Modernization Act is fairly strict as to what constitutes appropriate storage conditions under the rule.
The Produce Safety Rule proposes that storage of the final composted product be done in a manner that prevents a reintroduction of fresh animal derived materials. From the produce rule’s perspective, ensuring animals do not have access to compost piles and avoiding the mixing of piles of different ages are important to the integrity of the final product.
Applying compost can also be done in a manner that can reduce risk or enhance it. In general, if compost is applied in a manner that minimizes the potential for contact with the harvestable portion of the crop, it would be considered a lower risk than a broadcast application over the top of a crop. Aim to minimize direct contact of compost with the crop as much as practical.
If you have specific questions about food safety aspects of compost use or have difficulty tailoring good agricultural practices (GAPs) to your farm, contact the Michigan State University Extension Agrifood Safety Work Group at firstname.lastname@example.org or 517-788-4292.
Funding for this article was made possible in part by the Food and Drug Administration through grant PAR-16-137. The views expressed in the written materials do not necessarily reflect the official policies of the Department of Health and Human Services, nor does any mention of trade names, commercial practices or organization imply endorsement by the United States Government.
— Phil Tocco, Michigan State University Extension
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