The U.S. Food and Drug Administration is continuing to investigate Taylor Farms lettuce as the probable source of a multistate Cyclospora outbreak, even after a laboratory test that had initially identified the supplier's product was retracted as a false positive. Federal health officials say epidemiological evidence and traceback investigations still point to the company's romaine and other lettuce varieties as the most likely vehicle of the parasite.

Cyclospora cayetanensis is a microscopic intestinal parasite that causes cyclosporiasis, a diarrheal illness that can last weeks if untreated. Outbreaks in the United States are typically linked to fresh produce imported from or processed in regions where the parasite is endemic. Symptoms include watery diarrhea, stomach cramps, nausea, fatigue, and loss of appetite.

The retracted test result added a layer of complexity to the investigation. Authorities acknowledged the laboratory error but emphasized that the false positive does not exonerate Taylor Farms, as the broader body of evidence — including case-patient interviews and supply chain analysis — has consistently implicated lettuce from the supplier. The FDA said it is conducting additional environmental and product testing to confirm the source.

Some of the reported illnesses have been connected to consumers who ate at Taco Bell locations, where Taylor Farms supplies lettuce and other fresh ingredients. The chain has said it is cooperating fully with federal investigators. The total number of confirmed cases spans multiple states, though health officials have not yet released a final case count as the investigation remains active.

The episode has drawn attention to the challenges of food safety traceability, particularly when initial test results are retracted and public confidence in the investigation process is affected. The FDA has urged consumers who experience symptoms of cyclosporiasis to contact a healthcare provider, and the agency said it will issue updated guidance as new findings emerge.