FDA reverses Taylor Farms lettuce cyclospora test result
Federal officials now say a Taylor Farms lettuce sample did not test positive for cyclospora, but the company’s recall remains in place.
By Georgia Hale · Staff Writer
3 min read
A lettuce sample tied to Taylor Farms de Mexico did not test positive for cyclospora after all, the U.S. Food and Drug Administration said Sunday, reversing a result it had reported a day earlier during its investigation of a multi-state outbreak.
The FDA said it re-reviewed the testing and determined the earlier result was a false positive. In its Sunday statement, the agency said that, as of July 19, there were no confirmed positive product test results for cyclospora.
The reversal does not end Taylor Farms’ voluntary recall of iceberg lettuce sourced from central Mexico. The FDA said it is still working with the company to make sure product connected to the outbreak has been taken off the market.
Taylor Farms said Sunday night that the FDA had made an error and apologized, and the company echoed the agency’s update that no product sample has been confirmed positive for cyclospora. Taylor Farms said it would continue cooperating with public health officials as they investigate where the outbreak began.
Recall remains in place
Taylor Farms de Mexico announced Friday that it was voluntarily recalling iceberg lettuce from central Mexico from the U.S. market because of possible cyclospora contamination, according to the company and the FDA.
The FDA said the recalled products had been sent to stores in 27 states. The agency also said it had focused on the lettuce after identifying product supplied to Taco Bell restaurants in five states where people ate before becoming sick.
Taco Bell said Friday that it would stop using the producer for lettuce. The FDA separately warned consumers not to eat shredded iceberg lettuce from Mexico served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia.
On Saturday, the FDA had posted a notice saying a sample had tested positive. That update has since been removed from the agency’s outbreak page. At the time, the FDA said the product was not part of the existing Taylor Farms recall and that the company was trying to determine whether any of the lot was still in commerce or in consumers’ homes.
What the FDA says went wrong
The FDA said the Saturday test result was caused by false amplification, meaning it did not reflect a true positive finding for the parasite.
Amplification is a lab process that creates copies of sample material so investigators can more easily look for pathogens. Research published in the Annals of Clinical & Laboratory Science says amplification-based methods are routinely used in clinical labs to detect organisms that do not grow in conventional culture media.
The CDC says nearly 7,000 cyclosporiasis cases have been confirmed or are under investigation in the United States since May 1. Experts say the foodborne illness can cause severe watery diarrhea, fatigue and loss of appetite.
Thomas Gremillion, director of food policy at the Consumer Federation of America, said last week that cyclospora is hard to grow in a lab.
Donald W. Schaffner, chair of food science at Rutgers University, said Sunday by email that Taylor Farms was right to recall the product regardless of the lab result, and he credited the FDA for acknowledging the mistake.
Schaffner said testing for the organism is difficult and false positives can happen. He also said the episode could add confusion for consumers and that regulators should release more information when they announce positive findings, including false-positive rates.
This story draws on original reporting from NBC News.