FDA declares Taylor Farms lettuce cyclospora test a false positive

The Food and Drug Administration announced Sunday that a laboratory test indicating cyclospora contamination in a sample of Taylor Farms lettuce was a false positive. FDA experts re-examined the results and concluded the finding did not represent true amplification of the parasite.

The agency added that, as of that day, it had not identified any confirmed positive product samples for cyclospora testing. Taylor Farms had earlier said it was voluntarily removing iceberg lettuce sourced from central Mexico after the crop was linked to a multistate cyclosporiasis outbreak.

"While the FDA traceback is indicating a specific independent farm, which represents less than 1% of the U.S.'s iceberg lettuce supply, as the potential source of the outbreak, we have removed all iceberg lettuce from the region indefinitely," the company said.

The company also expressed sympathy for those affected and pledged continued cooperation with public-health authorities.

The Centers for Disease Control and Prevention had previously identified lettuce supplied to select Taco Bell locations in several states as a source of the outbreak, prompting the chain to remove the product. Walmart similarly withdrew certain bagged iceberg lettuce salads from stores, though it said there was no indication that its products were linked to the investigation.

The outbreak, first reported in May, has reached 34 states and sickened more than 1,600 people according to CDC data, with state health departments reporting higher numbers. No deaths have been reported. Cyclosporiasis is a food- and water-borne illness that causes prolonged watery diarrhea.