Mexico Says FDA Lettuce Probe Did Not Determine How Contamination Occurred

Packages of Taylor Farms salad greens at a Safeway store in Kings Beach, Calif., on July 16, 2026. Justin Sullivan/Getty Images

The Mexican Health Ministry said that a U.S. Food and Drug Administration investigation into a Cyclospora parasite outbreak that was traced to iceberg lettuce from Mexico did not conclusively determine how the contamination occurred.

Mexico’s food-safety regulator, Cofepris, said its laboratory tested raw materials, finished products and water from the facility investigated in the outbreak and found no Cyclospora. Cofepris’s Oct. 3 statement did not mention Taylor Farms’ Mexican subsidiary, but the FDA’s Oct. 2 update did so several times.

Cofepris said environmental findings alone were not conclusive evidence that agricultural products were the source of contamination.

Mexico said it had cooperated throughout the investigation by providing traceability information, inspections, and samples, and would continue to cooperate with U.S. health authorities.

The FDA announced Friday that it had closed its investigation into the Cyclospora outbreak. It said there was strong evidence linking the outbreak to recalled shredded iceberg lettuce from Taylor Farms’ subsidiary in Mexico.

“While there is currently not enough evidence to conclusively determine how contamination occurred in this outbreak, the positive samples show that Cyclospora was present in the environment where lettuce was grown and processed,” the FDA stated in its Oct. 2 update.

“This adds to the strong epidemiological data and traceback convergence supporting the link between this outbreak and recalled shredded iceberg lettuce from Taylor Farms de Mexico.”

Two samples from FDA inspections in Mexico tested positive. One was from a tank holding outgoing wastewater from Taylor Farms’ Mexico processing facility. The other sample was from a drainage ditch at an iceberg lettuce grower identified in the traceback.

Taylor Farms did not respond to an email seeking comment.

Although the outbreak investigation has closed, the FDA said follow-up work would continue with U.S. and international partners to inform prevention efforts. The agency said it remained confident that all recalled iceberg lettuce associated with the outbreak was off the market.

The Centers for Disease Control and Prevention declared an end to the Cyclospora outbreak linked to iceberg lettuce that began on Sept. 11. According to the CDC, the outbreak led to 12,883 cases across 21 states, with 570 hospitalizations and two deaths.

Cyclospora is a microscopic parasite that infects the small intestine. People get sick by eating food or drinking water contaminated with human feces containing parasites, such as in fresh produce.

Symptoms include watery diarrhea, loss of appetite, weight loss, stomach cramps, bloating, gas, nausea, and fatigue. Vomiting, low fever, and body aches are less common.

The illness can last from a few days to a month or longer and can come and go if left untreated.

Kimberly Hayek contributed to this report.