FDA says Taylor Farms lettuce test was false positive as Mexico-linked U.S. cyclospora investigation continues

Taylor Farms and Sysco withdrew iceberg lettuce sourced from central Mexico on July 17, 2026, as U.S. authorities investigated a cyclospora outbreak described by Reuters as one of the largest foodborne-illness outbreaks in the United States in recent years.

Two days later, the U.S. Food and Drug Administration said a test associated with Taylor Farms was a false positive. The agency also said the result did not end or change the broader investigation, leaving the final source of the outbreak unresolved.

What the companies did

Taylor Farms, a major food supplier, and Sysco, a major distributor, removed the iceberg lettuce from their supply chains as a precaution while the investigation proceeded. The lettuce had been sourced from central Mexico and moved through U.S. food-service and restaurant networks.

The withdrawals show how a food-safety investigation can quickly cross borders even when the immediate public-health inquiry is centered in the United States. Mexican agricultural supply was connected to U.S. distributors, restaurant customers and other food-service buyers, making traceability and timely communication central concerns for companies handling the product.

The available reports do not establish how much lettuce was withdrawn or provide a complete list of downstream buyers. They also do not establish the final outbreak source or the total number of illnesses.

FDA test result did not close the case

In an update reported July 19, Reuters said the FDA determined that a lettuce test linked to Taylor Farms was a false positive. Taylor Fresh Foods said it had been told about the FDA error.

That finding narrowed the significance of the particular test, but it did not clear every supplier, product or shipment connected to the investigation. The FDA said the broader cyclospora inquiry was continuing. The result also should not be read as evidence that all iceberg lettuce from Mexico was unsafe.

Taylor Farms said its branded salads and kits were not associated with the outbreak and did not contain the implicated iceberg lettuce. That statement describes the company’s position about its products; it does not resolve the wider investigation.

Restaurant customers report no effect

Wendy’s and Chipotle said their products were not affected, according to the Reuters reporting. Their statements indicate that the withdrawals did not apply across every restaurant supply chain, although the available sources do not provide a full accounting of affected or unaffected buyers.

For restaurants and food-service companies, the episode underscores the practical stakes of identifying the origin and distribution path of a potentially implicated ingredient. A supplier withdrawal can affect purchasing, menu planning, inventory handling and customer communications even before investigators determine whether a particular product caused illnesses.

For consumers, the central distinction is between precautionary supply-chain action and a confirmed finding. Taylor Farms and Sysco removed the lettuce while the investigation was underway; the sources do not say that Taylor Farms-branded salads caused the outbreak, and the FDA’s false-positive finding did not settle the overall case.

What happens next

The FDA’s investigation remains the next known step. Authorities still need to determine the outbreak’s source and establish the total number of illnesses, while companies and regulators continue working through product traceability and the scope of any affected distribution.

Until that work is complete, the July 17 withdrawals and the July 19 FDA update provide different pieces of the same developing story: a cross-border food-supply response was taken, one test was later identified as a false positive, and the broader U.S. cyclospora investigation remained open.