(Zero Hedge)—A sample of lettuce from a U.S. supplier did not actually test positive for a parasite called Cyclospora, the Food and Drug Administration said on July 19.

Regulators on Saturday said that the sample of shredded lettuce from Taylor Farms tested positive for the parasite.

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“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 a statement on Sunday.

Regulatory officials notified Taylor Farms of the development and are collecting and analyzing additional samples with state partners.

Taylor Farms said in a statement that it was informed that the announcement of the positive test was based on “a mistake” and that the FDA had informed the company of the false positive.

“To be clear, at this moment, FDA has not identified a single positive product test result for Cyclospora,” Taylor Farms said.

It emphasized that Taylor Farms products other than iceberg lettuce have not been implicated in the outbreak.

Cyclospora is a parasite in produce and water contaminated with feces. Cyclospora causes cyclosporiasis, the primary symptom of which is explosive diarrhea. Thousands of cyclosporiasis cases have been recorded across the country in recent months, a number much higher than the typical cyclosporiasis season.

Taylor Farms initiated a recall of iceberg lettuce on July 17 because of information it said was provided by the FDA. The lettuce, which originated in Mexico, was distributed to 27 states from June 19 through July 16.

The following day, the FDA announced that a sample collected during the investigation of the outbreak tested positive for Cyclospora and that it was not covered by the recall.

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

It still recommends that people and companies that purchased or received the recalled iceberg lettuce throw it out and seek refunds at the locations of purchase.

The iceberg lettuce was served at Taco Bell locations and possibly other restaurants, and people should avoid eating it at any of those restaurants, regulators said. Taco Bell has said it removed all Taylor Farms lettuce from its stores.

The Centers for Disease Control and Prevention advises individuals experiencing symptoms of cyclosporiasis, including watery, explosive diarrhea and loss of appetite, to see a doctor. Cyclosporiasis cases can only be confirmed through stool testing.