FDA says Taylor Farms lettuce test was false positive

A federal test that appeared to find cyclospora in a Taylor Farms lettuce sample was wrong, the Food and Drug Administration said Sunday, adding a new twist to a multistate outbreak that has sickened thousands of people and prompted lettuce removals from restaurants and stores.

The FDA said its laboratory experts re-reviewed results from a sample from Taylor Farms de Mexico and determined the earlier finding should be treated as a false positive.

“Due to the complexity in detection of Cyclospora, FDA laboratory experts re-reviewed the sample results and have concluded that the finding does not represent true amplification and should be considered a false positive,” the agency said.

“As of July 19, 2026, there are no confirmed positive sample results for product testing for Cyclospora,” the FDA said in a statement cited by NBC News. CBS News reported the FDA said Sunday it had not found any “confirmed positive sample results for product testing for Cyclospora.”

The reversal does not change Taylor Farms’ earlier voluntary action involving iceberg lettuce sourced from central Mexico. The company said Friday it was “voluntarily removing” iceberg lettuce from the region after the lettuce was linked to one of the largest U.S. cyclosporiasis outbreaks in recent years.

“While the FDA traceback is indicating a specific independent farm, which represents less than 1% of the U.S.’s iceberg lettuce supply, as the potential source of the outbreak, we have removed all iceberg lettuce from the region indefinitely,” Taylor Farms said Friday.

In a statement Sunday after the FDA announced the false positive, Taylor Farms said, “Our thoughts remain with everyone who has fallen ill in this outbreak. We are committed to working with public health authorities as the ongoing outbreak investigation continues.” NBC News reported that Taylor Farms also said the FDA made a mistake and apologized, and that the agency had not identified a “single positive product test result for Cyclospora.”

The Centers for Disease Control and Prevention identified lettuce supplied to select Taco Bell restaurants as a source of the outbreak on Thursday, more than a month after cases first began appearing. The CDC said the iceberg lettuce was distributed to Taco Bell restaurants in Indiana, Kentucky, Michigan, Ohio and West Virginia. Taco Bell said Friday it had “completed removal of affected Taylor Farms lettuce from our restaurants.” NBC News reported Taco Bell also said it would no longer use the producer for its lettuce.

The FDA warned consumers Friday: “Do not eat shredded iceberg lettuce from Mexico served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia.”

Walmart said over the weekend it had removed four Marketside bagged iceberg lettuce salad products from stores in more than two dozen states, while adding there was “no indication that products sold in our stores are affected by the current Cyclospora investigations.” NBC News reported the recalled Taylor Farms products had been distributed to stores in 27 states, according to the FDA.

Case counts vary by reporting source. CBS News reported the outbreak, first reported in May, had spread to 34 states and sickened more than 1,600 people, according to the CDC, while noting that state health departments have reported larger numbers, including more than 5,000 confirmed cases in Michigan as of Friday. NBC News reported that nearly 7,000 cases of cyclosporiasis have been confirmed or are under investigation in the U.S. since May 1, according to the CDC. No deaths have been reported.

Cyclosporiasis is a food- and waterborne illness caused by the cyclospora parasite. Public health experts say it can cause long-lasting, watery and sometimes explosive diarrhea; NBC News also cited experts saying symptoms can include fatigue or loss of appetite.

Donald W. Schaffner, chair of the Department of Food Science at Rutgers University, told NBC News by email that the Taylor Farms recall was “the right thing” to do regardless of the lab test’s status. He said the FDA showed courage by admitting its error, but added, “False positives are always possible.”