Backyard-style compost operations pose higher food safety risks
Nie K, McWright L, Rothwell JG, Mondragon-Becerra M, Malal H
Composting
That bag of compost you're about to dig into your vegetable bed could carry Salmonella or toxin-producing E. coli if it came from a loosely regulated processor instead of a certified facility.
Compost helps gardens grow, but not all compost is made the same way. Researchers tested compost from across California and found that certified, well-regulated facilities almost always killed off harmful germs, while smaller, less-monitored operations sometimes let dangerous bacteria like Salmonella survive. The takeaway: where your compost comes from matters just as much as what's in it.
Key Findings
184 finished compost samples were tested across 35 California organic waste processing sites
69.4% of registered facility samples (75 of 108) met the fecal coliform safety limit of ≤1,000 MPN per gram; no pathogens were detected at these sites
Alternative, less-regulated processing units had significantly higher fecal coliform levels (β = 1.37) and were the only sites where foodborne pathogens like Salmonella and E. coli were found
chevron_right Technical Summary
A California study of compost from 35 facilities found that officially registered composting operations almost always met safety standards for pathogen reduction, while less-regulated alternative composting sites were the only source of dangerous contamination like Salmonella and E. coli.
Abstract Preview
Original paper
Microbial Food Safety Risk in Finished Soil Amendments: A Statewide Cross-Sectional Study of Organic Waste Processing Systems in California.
Organic soil amendments, particularly compost, are widely used in organic agriculture because of their benefits to soil health and environmental sustainability. Commercial compost producers are gen...
open_in_new Read full abstractAbstract copyright held by the original publisher.
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