Skip to main content

FDA confirms cyclospora-linked lettuce sample from Taylor Farms was false positive

There have been no confirmed positive sample results for product testing for cyclospora, the FDA says

FILE - This undated photo taken through a microscope provided by the CDC shows Cyclospora cayetanensis oocysts found in a fresh stool sample which had been prepared with a formalin solution and stained with safranin. (CDC via AP, File) (Melanie Moser)

Federal officials are walking back claims over the weekend that a sample of Taylor Farms iceberg lettuce grown in central Mexico showed evidence of cyclospora, now referring to it as a “false positive.”

The U.S. Food and Drug Administration (FDA) reported on July 17 that a traceback investigation into the ongoing multi-state cyclosporiasis outbreak identified shredded lettuce from Taylor Farms De Mexico — which was sold at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia — as a possible convergence source, leading the company to issue a voluntary recall.

Recommended Videos


However, on Sunday the FDA said the sample test was false, noting there have been no confirmed positive sample results for product testing for cyclospora as of yet.

The voluntary recall by Taylor Farms also covered Marketside-brand products sold at Walmart across multiple states — including Michigan — described as “iceberg salad” or “shredded lettuce” with best by dates of of July 18-Aug. 3.

No other Taylor Farms products were included in the recall, the company reported.

On July 20, the Michigan Department of Health and Human Services (MDHHS) reported 6,148 cyclosporiasis cases since June 22, up from 5,002 on July 17. Of those reported cases, 102 were hospitalized as of July 20.

The cases remain the highest in Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland and Livingston counties.

The CDC said cases have been identified in 34 states and expects illnesses to continue increasing through the end of August, when the typical Cyclospora season ends.

The FDA says it is continuing to work with state partners to collect and analyze product samples for potential contamination. Taco Bell has also agreed to stop using lettuce from the supplier identified through the FDA’s traceback investigation, the agency said.

What is Cyclospora?

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis. Symptoms include prolonged diarrhea, stomach cramps, nausea, loss of appetite, fatigue, and weight loss.

Investigation ongoing

Health officials emphasized the investigation remains ongoing, and additional suppliers, restaurants, retailers or distribution channels could be identified as investigators continue tracing the source of the contamination.

The FDA noted that outbreak case totals may differ from figures reported by individual states because federal agencies count only confirmed cases, while some states also report probable cases.

National surveillance data also include laboratory-confirmed Cyclospora infections unrelated to the Taco Bell outbreak.