WASHINGTON (AP) — Federal health officials said Monday they remain focused on lettuce from Taylor Farms as the source of a multistate outbreak of a diarrhea-causing parasite, despite inaccurate test results that the government briefly publicized over the weekend.
Food and Drug Administration officials on Monday said a laboratory test incorrectly identified a positive result for cyclospora on a sample of lettuce from Taylor Farms. The FDA posted the finding to its website on Saturday but then said Sunday that the result had been a false positive.
Federal and state authorities have been investigating a rise in cases of the parasite, initially linking the outbreak in five states to lettuce served at Taco Bell locations. On Saturday, Taylor Farms announced it was recalling 25 shredded lettuce and salad mix products sold under eight different brand codes. The products are used by a number of U.S. food chains and suppliers.
“FDA’s traceback investigation and the outbreak data continue to converge on shredded iceberg lettuce from Taylor Farms’ locations in central Mexico,” FDA’s acting food chief, Donald Prater, told reporters on Monday.
READ MORE: What you need to know about the cyclosporiasis outbreak
In addition to tracing the supply chain of lettuce, FDA staff have begun testing samples of produce coming across the U.S. border.
FDA officials on Monday said the false positive result came from a rapid test used to screen for traces of cyclospora. The sample that initially appeared positive for the parasite came from Taylor Farms but was not part of the company’s lettuce recall. FDA officials said they felt compelled to alert the public to the finding.
But a subsequent quality control check showed the positive finding was an error. FDA officials notified Taylor Farms of that on Sunday.
The company touted the updated test results on social media and claimed “FDA apologized to us.” Agency officials said there was no official apology.
Cyclospora is a microscopic parasite that infects food that has come into contact with human feces, most commonly when produce is irrigated or washed with contaminated water. When ingested, the parasite causes intestinal illness marked by “frequent and sometimes explosive bowel movements,” according to the CDC.
Cyclospora cayetanensis oocysts seen under a microscope. Photo by CDC via AP
In 2026, cyclospora has sickened at least 1,645 people in the U.S. and hospitalized 141, according to the FDA and CDC. The agencies are investigating five separate clusters of illnesses, including the one traced to Taylor Farms.
FDA’s acting commissioner, Kyle Diamantas, said health officials have continued to see new cases associated with the latest outbreak, including some as recent as last week.
“Which means it’s imperative for us to take action to ensure that contaminated product is not making its way to the market,” Diamantas explained.
As of Friday, foot traffic was down at a number of dining chains compared with the day-of-the-week averages between Jan. 1 and July 6, according to Placer.ai, which tracks people’s movements based on cellphone usage.
Taco Bell suffered the biggest drop — an 18.9% decline — after federal health officials named the chain in its investigation of the cyclosporiasis outbreak. Foot traffic fell 14.3% at Chopt, Placer.ai said. Both Chipotle and Panera Bread had close to a 7% drop in traffic, while Cava’s drop was less — at 4.2% — according to the firm.
Food safety investigators often cannot draw a direct biological connection between recalled produce and outbreaks of foodborne illness. Some common tests used to check for food poisoning have not been geared to detect cyclospora. Technicians aren’t able to grow the parasite in labs, making it hard to draw evidence from contaminated produce.
Instead, investigators draw conclusions based on accounts of what people ate, the proximity and timing of cases and other patterns.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
