The FDA 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.