FDA confirms Taylor Farms lettuce cyclospora test was false positive

FDA confirms a Taylor Farms lettuce sample initially reported positive for cyclospora was actually a false positive due to testing complexity.

Objective Facts

The FDA discovered the false positive when reviewing a sample from Taylor Farms de Mexico that was initially reported positive on Saturday, and as of July 19, 2026, there are no confirmed positive sample results for cyclospora. Due to the complexity in detecting cyclospora, FDA laboratory experts re-reviewed the sample results and concluded that the finding does not represent true amplification and should be considered a false positive. Taylor Farms said the FDA made a mistake and apologized for the false positive. The false positive does not change the company's earlier voluntary recall of its iceberg lettuce that was sourced from central Mexico. The recalled products had been distributed to stores in 27 states, and the recall came after the FDA identified the product as having been provided to Taco Bell locations in five states where people ate before being sickened.

Deep Dive

Cyclospora cayetanensis cannot be grown—there is no culture system and no animal model—so nothing can be enriched before testing; detection in food is washing the produce and running PCR on whatever DNA comes out. Thomas Gremillion, director of food policy at the Consumer Federation of America, said it is "really hard to grow cyclospora in the lab". This technical limitation explains why the FDA faces inherent challenges in testing produce samples, and amplification-based testing methods—which create copies of DNA samples to make detection easier—can be prone to false positives when interpreting results, especially with a parasite as difficult to cultivate as cyclospora. Donald Schaffner stated that the Taylor Farms recall was "the right thing" for the company to do regardless of lab test status, and that the FDA showed courage in admitting it was wrong. Schaffner said regulatory agencies should have to provide more data when announcing positive results, including the false positive rate. The FDA's decision to both correct its error publicly and maintain the product recall reflects a precautionary approach—the agency is not claiming cyclospora is absent from the supply, only that this particular sample did not definitively confirm contamination through proper amplification. The broader outbreak context remains: Nearly 7,000 cases of cyclosporiasis have been confirmed or are under investigation in the United States since May 1, according to the Centers for Disease Control and Prevention, and there are 1,644 laboratory-confirmed infections in people who reported eating at Taco Bell across five states, with 94 hospitalizations, and Michigan pulled ingredient-level exposure detail from 190 of those cases and 90 percent reported eating iceberg lettuce. The epidemiological evidence linking Taylor Farms lettuce to illnesses came primarily from traceback investigation and patient exposure data, not from product sample testing—a distinction that underscores why the company maintained its recall even after the false positive finding.

FDA confirms Taylor Farms lettuce cyclospora test was false positive

FDA confirms a Taylor Farms lettuce sample initially reported positive for cyclospora was actually a false positive due to testing complexity.

Jul 20, 2026

What's Going On

The FDA announced Sunday that a lettuce sample from Taylor Farms de Mexico tested positive for cyclospora in a multistate outbreak investigation produced a false positive for the parasite.
The false positive was discovered when the FDA again reviewed the results of a sample from Taylor Farms de Mexico that was reported positive Saturday.
As of July 19, 2026, there are no confirmed positive sample results for product testing for Cyclospora, the FDA stated.
The false positive does not change the company's earlier voluntary recall of its iceberg lettuce that was sourced from central Mexico.
Donald W. Schaffner, chair of the department of food science at Rutgers University, said the Taylor Farms recall was "the right thing" for it to do, regardless of the status of lab tests, and said the FDA showed courage in admitting it was wrong about the positive test.

◆ All Sources (9)

CBS News - Taylor Farms lettuce sample that tested positive for cyclospora was a false positive, FDA says CNBC - FDA says Taylor Farms cyclospora finding was a false positive Food Safety News - FDA says Cyclospora test on lettuce from Taylor Farms was a false positive WSLS - FDA says Taylor Farms lettuce sample tested for cyclospora produced false positive Newsweek - Taylor Farms Says FDA Has Apologized Over False Positive Cyclospora Test NewsNation - Explosive diarrhea outbreak: FDA says positive Cyclospora test linked to lettuce was false alarm Marler Blog - FDA's Cyclospora Positive Yesterday Is a False Positive Today The Epoch Times - Lettuce Sample That Tested for Cyclospora Was a False Positive: FDA NBC News - Taylor Farms lettuce sample produced false positive for cyclospora, FDA says

Objective Deep Dive

Donald Schaffner stated that the Taylor Farms recall was "the right thing" for the company to do regardless of lab test status, and that the FDA showed courage in admitting it was wrong. Schaffner said regulatory agencies should have to provide more data when announcing positive results, including the false positive rate. The FDA's decision to both correct its error publicly and maintain the product recall reflects a precautionary approach—the agency is not claiming cyclospora is absent from the supply, only that this particular sample did not definitively confirm contamination through proper amplification.

The broader outbreak context remains: Nearly 7,000 cases of cyclosporiasis have been confirmed or are under investigation in the United States since May 1, according to the Centers for Disease Control and Prevention, and there are 1,644 laboratory-confirmed infections in people who reported eating at Taco Bell across five states, with 94 hospitalizations, and Michigan pulled ingredient-level exposure detail from 190 of those cases and 90 percent reported eating iceberg lettuce. The epidemiological evidence linking Taylor Farms lettuce to illnesses came primarily from traceback investigation and patient exposure data, not from product sample testing—a distinction that underscores why the company maintained its recall even after the false positive finding.