Taylor Farms remains the subject of a Food and Drug Administration investigation in connection with the growing outbreak of cyclosporiasis, despite a false positive test result, the agency said Monday.
Late Sunday, the FDA reported that a sample of the company’s lettuce had tested false positive for Cyclospora, the parasite that causes the disease.
However, that sample did not come from lettuce already implicated in the outbreak and recall. Instead, it came from a different shipment that the agency picked up during routine import inspections.
“To clarify, this false positive laboratory sample does NOT change the basis of the FDA’s ongoing investigation into the outbreak or the overwhelming epidemiological data supporting the current voluntary product recall by Taylor Farms,” the FDA stated this Monday on the social network X.
On Sunday, Taylor Farms said in a statement that the FDA had “apologized” for the false positive test results. In a call Monday, an FDA official refuted Taylor Farms’ claim that the agency had issued an official apology.
Taylor Farms did not immediately respond to requests for comment.
(Here’s what you should know about outbreaks of cyclosporiasis, a foodborne illness.)
Determining the origin of an outbreak goes beyond finding a positive sample.
Public health officials are not based solely on laboratory tests to identify the source of a food-borne outbreak, said Donald Schaffner, professor of Food Microbiology and director of the Department of Food Sciences at Rutgers University.
Instead, researchers analyze patient samples and interviews, food receipts and food supply chain information to determine where the contaminated food likely came from.
In the current outbreak, researchers found that many of the people who became ill had eaten at Taco Bell restaurants stocked with Taylor Farms lettuce. As of Saturday, the Centers for Disease Control and Prevention (CDC) had confirmed more than 1,600 cases in people in Indiana, Kentucky, Michigan, Ohio and West Virginia.
“Taylor Farms remains involved due to epidemiology,” Schaffner wrote in an email. “This means that people who They ate at Taco Bell and consumed lettuce from Taylor Farms are sick with the parasite.
It is important to realize that this is just a statistical correlation. “Correlation does not imply causation, but it was strong enough evidence for the FDA and CDC to believe this is the cause.”
On Saturday, Taco Bell announced that it had removed all Taylor Farms lettuce from its restaurants in the United States.
Schaffner noted that it is unusual for researchers to be able to detect the Cyclospora parasite in a food sample.
“It is almost always too late because the food has already spoiled or has already been consumed,” he said.
A positive result for the parasite would have been very strong confirmatory data, said Don Stoeckel, an environmental microbiologist and associate member of the Produce Safety Alliance, a food safety training group.
However, the lack of a positive result “does not reduce the importance to follow the CDC recommendation to avoid consumption of the product mentioned on the CDC research page,” Stoeckel said.
