The U.S. Food and Drug Administration is releasing the findings of a sampling assignment that tested raw agricultural commodity romaine lettuce mostly at facilities and on farms in the Salinas, California, and Yuma, Arizona, growing regions for the presence of pathogens that have been linked to outbreaks of foodborne illness.
The assignment to detect pathogenic Escherichia coli (specifically, Shiga toxin-producing E. coli or STEC) and Salmonella spp. began in November 2019 and ended in December 2020, after a pause in sample collection and testing from March through October 2020 due to the COVID-19 pandemic. The FDA did not detect any pathogens during the assignment.
The agency prioritized sample collection at farms and FDA-registered facilities identified in traceback investigations as suppliers of romaine lettuce possibly linked or linked to outbreaks of foodborne illnesses from 2017 to 2019. The FDA collected and tested 279 samples for both pathogens. Each sample was made up of 10 subsamples, with each subsample consisting of one or more heads or hearts of romaine lettuce and weighing at least 300 grams.
This approach – the collection and testing of samples composed of multiple subsamples – increases the probability of detecting pathogens if present, given that microbial hazards may not be uniformly present. Agency field staff collected all samples in their natural form but for the outer leaves having been removed. No fresh-cut lettuce was collected.
Ensuring the microbiological safety of leafy greens continues to be a priority to the FDA. Although no pathogens were detected during this assignment, maintaining surveillance during the growing/harvesting season is helpful to informing the agency’s leafy greens prevention efforts, specifically those outlined in the FDA’s Leafy Greens Action Plan. The FDA originally released the action plan in March 2020 to foster a more urgent and collaborative approach to preventing leafy greens outbreaks caused by STEC. In April 2021, the FDA released an updated version of the plan which reaffirms our commitment to advancing leafy greens safety.
