FDA Releases Risk Assessment of Foodborne Illness Associated with Pathogens from Produce Grown in Fields Amended with Untreated Biological Soil Amendments of Animal Origin

Constituent Update

March 12, 2026

The Food and Drug Administration is releasing a risk assessment that was conducted to evaluate and quantify the risk of human illness associated with consumption of produce grown in fields or other growing areas with untreated biological soil amendments of animal origin (BSAAO), including raw manure. Results of the risk assessment will be used to inform policy decisions regarding appropriate standards for the use of raw manure and other untreated BSAAO when growing produce.

Pathogens on produce, such as Shiga toxin-producing Escherichia coli (STEC) O157:H7, Salmonella, and STEC non-O157 can cause human illness. The survival rate of pathogens from untreated BSAAO and their risk of contaminating crops are determined by various factors, including environmental conditions and agricultural practices. The FDA’s risk assessment investigated these factors and provides critical insights essential for protecting the nation's produce supply and helping to ensure safe food for all Americans.

The untreated BSAAO risk assessment was completed in two phases. Part 1 focused on pre-harvest practices and conditions to determine the likelihood of produce being contaminated with pathogens before it is picked. It specifically analyzes how interventions, such as the waiting period between applying untreated BSAAO and harvesting the crops, affect the potential concentration of pathogens on the produce at the time of harvest. Part 2 modelled the path of potentially contaminated produce from the farm through the supply chain to the consumer. It includes processing activities, potential for cross-contamination during processing, transportation and storage, produce consumption, and the amount of pathogen exposure (STEC O157:H7, Salmonella, and STEC non-O157) required to cause illness through consumption of the produce commodity.

The main conclusion of this risk assessment is that extending the time between the application of untreated BSAAO and produce harvest significantly reduces the potential level of human pathogens on produce at the time of harvest. The effectiveness of this waiting period varied among the human pathogens analyzed and type of untreated BSAAO, as influenced by regional environmental conditions and the initial level of human pathogens in the raw manure.

The risk assessment model may also serve as a tool for stakeholders and industry in evaluating risks that may be associated with their agricultural practices and environmental conditions.

Produce Safety Rule Context and Historical Reference

In 2013, the FDA initially proposed a produce safety rule with a 9-month waiting period for using certain untreated BSAAO. However, after receiving public comments that highlighted the need for more scientific research, the FDA did not finalize that requirement. The final rule, codified at 21 CFR part 112, does not include a specific waiting period, instead reserving a provision for a potential future standard, pending the completion of a risk assessment. With today’s release of this risk assessment, the FDA will consider the appropriate next steps. The FDA will continue to engage with the public and stakeholders on produce safety.

For More Information

Please refer to the Question and Answer document that may contain answers you may have pertaining to the use of BSAAO in your operation as well as the FDA rulemaking process in general associated with Subpart F in the produce safety rule. 

Risk Assessment contact: fdafoodsafetyriskmodel@fda.hhs.gov

Docket Access: For background documents or comments received, see Docket No. FDA 2016-N-0321.

Additional Resources:

• Final Produce Safety Rule: 80 FR 74354 (November 27, 2015)
• Supplemental Proposed Rule: 79 FR 58434 (September 29, 2014)
• Original Proposed Rule: 78 FR 3504 (January 16, 2013)
• Final Qualitative Assessment of Risk to Public Health from On-Farm Contamination of Produce
• FDA postharvest processing Model
• FDA Leafy Green Risk Assessment Model
• FDA-Melon Quantitative Risk Assessment-Epidemic Curve Prediction (QRA-EC) Model
• Risk Assessment of Foodborne Illness Associated with Pathogens from Produce Grown in Fields Amended with Untreated Biological Soil Amendments of Animal Origin – Part 1: Preharvest Exposure Assessment
• Risk Assessment of Foodborne Illness Associated with Pathogens from Produce Grown in Fields Amended with Untreated Biological Soil Amendments of Animal Origin – Part 2: Postharvest Exposure Assessment, Dose Response, and Risk Characterization
• FDA Biological Soil Amendments of Animal Origin (BSAAO)-Produce Risk Assessment Output Explorer
• FDA’S Response to Peer Review Comments on the FDA’s Risk Assessment of Foodborne Illness Associated with Pathogens from Produce Grown in Fields Amended with Untreated Biological Soil Amendments of Animal Origin (BSAAO)
• Frequently Asked Questions: Biological Soil Amendments of Animal Origin under the FSMA Produce Safety Rule 

This constituent update is intended to provide stakeholders with information about FDA's ongoing risk assessment activities. FDA encourages all interested parties to submit relevant scientific data and information to support this important public health initiative.