FDA still points to Taylor Farms lettuce after cyclosporiasis test reversal

The FDA has walked back one lab result in its cyclosporiasis investigation, but it is keeping its main warning in place: recalled iceberg lettuce tied to Taylor Farms remains under scrutiny. For investors watching restaurants and grocers, the issue is less about one test and more about how food-safety uncertainty can hit traffic, supply chains and brand trust.

The Food and Drug Administration said Sunday that a test suggesting a sample of iceberg lettuce from Taylor Farms de Mexico contained the Cyclospora parasite was a false positive. A false positive means an early test showed a result that later confirmation testing did not support.

On Monday, the agency said that reversal applied only to one shipment and did not change its broader view of the outbreak. The FDA said its traceback work and outbreak data still point to shredded iceberg lettuce from Taylor Farms locations in central Mexico.

“FDA’s traceback investigation and outbreak data continue to converge on shredded iceberg lettuce from Taylor Farms locations in central Mexico,” the agency said in a statement posted on X. The FDA said it is still working with federal and state partners and is focused on making sure affected products are out of the market.

What the investigation still says

The outbreak has sickened more than 1,600 people across 34 states, according to federal health officials cited in the investigation. Cyclosporiasis is caused by the Cyclospora parasite and can produce stomach illness that lasts days or weeks.

The FDA has said the lettuce was served at some Taco Bell restaurants, and it continues to advise consumers not to eat recalled iceberg lettuce. Taylor Farms said Monday that it would continue its voluntary recall of implicated iceberg lettuce from central Mexico.

Taco Bell said it had already begun removing the suspected lettuce from restaurants in affected states. In a Saturday statement, the chain said it voluntarily removed suspected lettuce from its locations within 72 hours of starting the process and adjusted its supply chain. Taco Bell also said it was confident customers could eat safely at its restaurants.

Former FDA Commissioner Dr. Scott Gottlieb told CNBC that the false positive does not clear Taylor Farms from being linked to the outbreak. He said the recall involved product imported weeks earlier and was separate from the lettuce sample tied to the disputed test result.

Gottlieb also noted that Cyclospora can take up to two weeks to cause illness after exposure, while lettuce has a short shelf life. That timing can make investigators test multiple shipments, even from the same farm.

Companies respond as consumers pull back

Walmart said Monday that it removed four Marketside bagged salad kit products supplied by Taylor Farms from stores in 27 states as a precaution. The retailer said there was no indication those products were part of the outbreak and that no confirmed illnesses had been linked to them.

Michigan’s Department of Health and Human Services said it still recommends that people buy whole heads of lettuce rather than pre-washed, bagged or pre-mixed salad kits. The agency said interviews with more than 2,000 infected patients showed many did not report eating lettuce at a restaurant, though many did report eating lettuce somewhere.

Dr. Norman Beatty, an associate professor of medicine at the University of Florida College of Medicine, told CNBC that the outbreak may still trace back to one lettuce vendor, but smaller related outbreaks could be found because of how the parasite spreads.

Restaurant traffic has already taken a hit. Placer.ai data cited by CNBC showed Taco Bell visits fell about 19% on Friday compared with the year-to-date average for that weekday. Chopt, Panera Bread and Chipotle also saw declines, according to the same data.

Yum Brands, Taco Bell’s parent company, has fallen nearly 9% over the past five days. Analysts cited by CNBC said they do not expect the outbreak to cause lasting financial damage for Taco Bell or other restaurant chains, though they said companies tied to the outbreak could see a one- to two-quarter impact.

This story draws on original reporting from CNBC.