By Phil Tocco
From an agronomic perspective, compost is unmatched as a soil builder and can greatly contribute to overall plant and soil health. From a food safety perspective, improperly composted material can be a hazard. Proper composting of animal-based parent material is essential to ensure a reduced risk of contamination. Improper composting can result in applying a product that could pose a food safety risk.
The Food Safety Modernization Act’s (FSMA) Produce Safety Rule calls compost a biological soil amendment (BSA). The particular biological soil amendments the U.S. Food and Drug Administration (FDA) has particular concern with are biological soil amendments of animal origin (BSAAO).
The FDA has determined composting is an effective BSAAO treatment process and can be safely used for use in covered activities under the Produce Safety Rule. Careful attention needs to be given to process controls, handling and conveyance practices to comply, however. The FDA offers two examples of a scientifically validated composting process for BSAAO material: An aerated static pile reaching 131 degrees Fahrenheit for three consecutive days, or a turned compost pile reaching 131 F for 15 days not necessarily consecutive, which must be turned at least five times to ensure processing to completion.
After the temperature requirements are met, there is an expectation that all compost will be cured. In the definition of curing used by the FDA for the rule, the temperature must fall below and stay below 131 F. Curing is finished when the temperature of the pile is the same as ambient air temperature.
If compost is produced on site, there is an expectation that temperature measurements and number of turnings (if turned) will be monitored and logged somewhere, possibly in a food safety manual, which must be available upon request. If compost is purchased, the seller must provide documentation at least annually that the treatment process has been scientifically validated and carried out with appropriate process controls, as well as documentation that the compost has been handled and stored correctly prior to delivery or receipt. There is no requirement that any compost needs to be tested for pathogens. This may be different if the same farm is seeking GAP certification.
If you have specific questions about compost use or have difficulty tailoring GAPs to your farm, contact Michigan State University Extension’s Agrifood Safety Work Group at gaps@msu.edu or 517-788-4292. To obtain more information on GAP compliant compost use, ask for guidance document AFSM027-01.
Source:msu.edu