‘false Positive’: Fda Walks Back Cyclosporiasis Test Tied To Taylor Farms

The Food and Drug Administration said that a lab test linking Taylor Farms iceberg lettuce products to an ongoing cyclosporiasis outbreak that has sickened thousands of people was a false positive.

The FDA’s investigation into the outbreak in five states is ongoing and it is advising consumers not to consume the recalled Taylor Farms products, which included those served in Taco Bell locations and sold at certain Walmart stores. The agency is continuing to work with the company to get the product off shelves.

“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 in a statement on Sunday, adding that it has no confirmed positive sample results at this time.

It is not uncommon for test results to be inconclusive, former FDA Commissioner Robert Califf told POLITICO.

“Equivocal tests are very common,” Califf said. “So is the human instinct to value a ‘test result’ more than a constellation of factors.”

On July 17, the FDA said its “traceback investigation identified convergence on a single supplier, Taylor Farms de Mexico, that provided shredded iceberg lettuce used by Taco Bell locations where sick people ate before becoming ill.”

But on Sunday, Taylor Farms said the FDA had “apologized” to the company for the false positive.

The company issued a recall for the lettuce “out of an abundance of caution” and said they are continuing to work with authorities to find the culprit.

“We are committed to working with public health authorities as the ongoing outbreak investigation continues,” Taylor Farms said in a statement.

Cyclospora is a parasite that is found on fresh produce and can cause diarrhea, leading to dehydration. Dozens of patients have been hospitalized and none have died, according to the latest data from the Centers for Disease Control and Prevention.

David Lim contributed to this report.