CT Parasite Outbreak Update: False Positive Revealed By FDA

The U.S. Food and Drug Administration on Sunday announced tests which linked lettuce from a Mexico-based company to the diarrhea-causing Cyclospora parasite last week showed a “false positive.”

The FDA had previously announced a lettuce sample from Taylor Farms de Mexico tested 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 FDA said, in the announcement.

On Friday, the FDA indicated its traceback investigation had led to Taylor Farms de Mexico, which had “provided shredded iceberg lettuce used by Taco Bell locations where sick people ate before becoming ill.”

“As of July 19, 2026, there are no confirmed positive sample results for product testing for Cyclospora,” Sunday’s FDA announcement said.

On July 17, Taylor Farms de Mexico announced it would voluntarily remove all iceberg lettuce sourced from central Mexico from the U.S. market, citing the potential for it to be contaminated with Cyclospora. The product had been distributed in several states, including Connecticut.

On Sunday, Taylor Fresh Foods issued a statement indicating the FDA had apologized to the company for the initial test result.

“We were informed that (the) FDA made a mistake, and this was a false positive,” the statement said. “To be clear, at this moment, FDA has not identified a single positive product test result for Cyclospora.”

The company said its recall of iceberg lettuce was voluntary and made based on initial information from health officials.

“Our thoughts remain with everyone who has fallen ill in this outbreak,” the company said. “We are committed to working with public health authorities as the ongoing outbreak investigation continues.”

Taco Bell announced on July 17 it had completed removal of all Taylor Farms lettuce from its restaurants “out of an abundance of caution.”

Cyclosporiasis is an intestinal illness caused by a parasite which gets into the body through contaminated food or water. Frequent, watery diarrhea is a common symptom, along with fatigue and loss of appetite.

The illness has been reported in 34 states as of July 13, according to the U.S. Centers for Disease Control and Prevention, or CDC.

Consumers can continue to take precautions to avoid the illness, including washing hands, and washing fresh produce thoroughly. Cooking produce can also kill the parasite.

Find advice from the CDC on preventing infection HERE.

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