The Food and Drug Administration announced that a laboratory test indicating cyclospora contamination in a specific shipment of iceberg lettuce from Taylor Farms de Mexico was a false positive. The agency clarified that this reversal does not alter its primary conclusion linking the multistate outbreak to shredded iceberg lettuce supplied by the company from central Mexico, some of which was served at Taco Bell locations. Officials continue to advise consumers to avoid recalled products from this supplier.
The outbreak has sickened more than 1,600 confirmed cases, with potentially thousands more affected. The parasite causes symptoms resembling severe gastrointestinal illness lasting days or weeks. Investigators are examining additional factors that may have contributed to the outbreak’s spread across more than 30 states. The FDA indicated it will continue working with federal and state partners to identify all potentially contaminated products and remove them from circulation.
The false positive has created additional uncertainty in an already complicated situation for both consumers and the food industry. Foot traffic at restaurants serving affected lettuce, including Taco Bell, declined significantly following outbreak publicity. Taco Bell removed suspected lettuce from locations within 72 hours and adjusted its supply chain, while Walmart proactively removed bagged salad products from 27 states. Taylor Farms continued its voluntary recall of iceberg lettuce from the implicated region.
Industry experts noted that false positives can occur during cyclospora testing when initial screening signals are not confirmed through subsequent laboratory procedures, as cyclospora is particularly difficult to reproduce in laboratory conditions. Analysts did not expect the outbreak to produce long-term financial damage to affected companies, though temporary sales impacts were anticipated. The investigation highlighted ongoing challenges in food safety traceability and the rapid response required when contamination is suspected in widely distributed fresh produce.