FDA says Taylor Farms cyclospora finding was a false positive, investigation continues

A lettuce sample supplied by Taylor Farms de Mexico that initially tested positive for cyclospora, the parasite linked to a growing “explosive diarrhea” outbreak, was later determined to be a false positive, the Food and Drug Administration (FDA) said in a statement on Sunday.

The FDA said laboratory experts reviewed again the test results and concluded the finding “does not represent true amplification and should be considered a false positive.” The agency removed information about the sample from a previous outbreak update and said there are currently no confirmed positive product samples for cyclospora, the parasite that causes cyclosporiasis.

Taylor Fresh Foods, the parent company, said the FDA notified them Saturday that one of its iceberg lettuce products from central Mexico had tested positive before later correcting the result.

The development comes days after Taylor Fresh Foods announced a voluntary recall of iceberg lettuce sourced from central Mexico following an FDA traceback investigation that identified Taylor Farms de Mexico as a common supplier linked to illnesses.

The company said it removed all iceberg lettuce from the region from the U.S. market after federal officials pointed to a specific farm as a potential source of the outbreak.

On Friday, the FDA advised consumers not to eat shredded iceberg lettuce from Mexico served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia. The agency said its investigation found convergence on Taylor Farms de Mexico as the supplier of shredded iceberg lettuce served at Taco Bell restaurants where some people became ill.

The FDA said it is continuing to work with Taylor Farms to ensure any products implicated in the outbreak are removed from the market while federal and state investigators continue collecting and testing samples.

Nearly 7,000 people may have been sickened nationwide in the broader cyclosporiasis outbreak, according to the Centers for Disease Control and Prevention. As of Friday, the CDC had confirmed 1,644 cases and was investigating more than 5,100 additional illnesses. No deaths have been reported.