Cyclospora False‑Positive Confuses US Lettuce Outbreak Investigation
Food‑ and drug‑law enforcement has revealed that a sample of iceberg lettuce supplied by Taylor Farms to the fast‑food chain Taco Bell tested positive for Cyclospora, an intestinal parasite that has caused a widespread diarrhoea outbreak. However, a re‑examination of the sample by the U.S. Food and Drug Administration (FDA) determined it was a false‑positive, leaving the true source of the parasite unclear.
The first cases of a Cyclospora infection were reported on 13 May, and CDC data now shows that players linked to iceberg lettuce from Taylor Farms have infected thousands of people, resulting in almost 100 hospitalisations. While no deaths have been recorded, symptoms can linger for days and include watery diarrhoea, weight loss and appetite loss.
In response, Taylor Farms voluntarily withdrew all Central‑Mexico‑sourced iceberg lettuce from the U.S. market and issued a list of affected products. The chain has confirmed it removed the implicated lettuce at all affected Taco Bell restaurants. The CDC advises against eating shredded iceberg lettuce served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia, but the authorities have not yet identified a definitive outbreak source.
Key Points for Consumers
- Re‑tests have shown the original positive result to be a false‑positive.
- Further surveillance is underway to trace the parasite’s true origin.
- Consumers should avoid Taco Bell shredded iceberg lettuce in the five states where the CDC warns of risk.
- Hospitalisations continue, but there are no known fatalities.
- Taylor Farms and the FDA are working to remove contaminated products from the market.
The outbreak has spotlighted the complex nature of Cyclospora testing and the ongoing challenges faced by food‑safety regulators in catching foodborne illnesses early.
