Federal health officials have identified lettuce from Mexico served at Taco Bell locations across five U.S. states as a source of a widespread outbreak of the diarrhea-causing parasite cyclospora. The Centers for Disease Control and Prevention warned consumers not to eat shredded iceberg lettuce from Taco Bell restaurants in Indiana, Kentucky, Michigan, Ohio, and West Virginia.

A record number of cyclospora cases have been reported in more than 30 states. The Food and Drug Administration investigation identified a single supplier of the lettuce, which a federal official briefed on the investigation identified as Taylor Farms of Salinas, California. Taylor Farms has been tied to foodborne outbreaks in the past.

Taco Bell has committed to stopping the use of lettuce from the identified supplier. Federal health officials stressed that other brands, restaurants, or retailers could be identified as the investigation continues. Cyclosporiasis is typically treated with antibiotics, and outbreaks tend to occur most often in the late spring and summer.