FDA declares largest-ever ‘explosive diarrhea’ outbreak over but origin still unknown

Federal health authorities have declared the largest cyclospora food‑poisoning outbreak in U.S. history over, after nearly 13,000 cases were linked to a multistate surge this year. The outbreak, which dominated reports across 21 states, was centered on iceberg lettuce and was the bulk of the unprecedented rise in parasitic diarrheal illness. The U.S. Food and Drug Administration said on Friday that all recalled iceberg lettuce associated with the outbreak has been removed from the market.

Despite the outbreak’s conclusion, questions about how the parasite entered the food supply remain. Cyclospora is spread through human feces, and officials are unclear how sewage could have contaminated enough produce to affect so many people. Ellen Shumaker, director of outreach for a North Carolina State University food‑safety program, explained that contamination can occur when produce grows in contaminated soil or comes into contact with polluted water.

Since May 1, the government has documented nearly 20,000 laboratory‑confirmed cases, a more than sixteenfold increase from the same period last year, and over 6,100 suspected cases. The previous worst year was 2019, when about 4,700 illnesses were reported nationally. Michigan was the hardest hit state, reporting the most cases and the two U.S. deaths linked to the outbreak. Thousands of other cases were not tied to the lettuce outbreak.

Investigators first traced the outbreak to lettuce served at Taco Bell, then identified Taylor Farms as the source of the contaminated iceberg lettuce grown in central Mexico. The recall covered thousands of packaged salad products shipped to major U.S. restaurant chains, including Yum Brands, the parent company of Taco Bell, Pizza Hut and KFC. The FDA has finished on‑site inspections and sample collection at the Mexican growers and processing facility, with analysis of those samples still pending. The outbreak has highlighted a growing concern that U.S. regulators are conducting fewer international inspections to catch contaminated produce before it reaches American consumers.