Shredded iceberg lettuce supplied to Taco Bell restaurants by California-based supplier Taylor Farms, which has a facility in Colorado Springs, has been ​identified by investigators as a ​potential source of contamination ‌in the cyclosporiasis outbreak that has sickened thousands of people in the U.S.

The Washington Post was first to ​report the Taylor Farms connection on Thursday, citing two individuals familiar with the investigation.

In 2024, Food and Drug Administration inspectors found dozens of violations at the Taylor Farms facility in Colorado Springs that supplied McDonald’s with slivered onions linked to an E. coli outbreak.

The FDA found the tainted slivered onions from Taylor Farms led to one death and more than 100 infections for people who ate the McDonald’s Quarter Pounder.

A Colorado Springs mother and her 10-year-old child sued McDonald’s and Taylor Farms after each of them ate a Double Quarter Pounder hamburger and were exposed to E. coli.

Thursday’s report did not specify which Taylor Farms distribution center supplied the lettuce to Taco Bell. Taylor Farms is based in Salinas, Calif., and has several supply facilities across the U.S.

While the U.S. has experienced outbreaks of the parasitic intestinal infection before, the scale and geographic spread of this year’s ⁠outbreak are significantly larger, prompting concern among health officials, Reuters reported.

The outbreak started May 1 and has been concentrated in Michigan, with Ohio and New York also reporting a large number of infections. Michigan health officials on Thursday reported 4,312 cases of the parasitic ​illness.

The U.S. Centers for Disease Control and Prevention said this week it had identified ⁠a likely link among cases reported in Michigan, ⁠Ohio, West Virginia and Kentucky, suggesting many of the infections may stem from a common source, ‌according to the report.

Taco Bell said earlier this week it had removed a ​limited number ​of ingredients from some restaurants as ‌a precautionary measure, ‌but stressed that U.S. health authorities had not linked the outbreak to the chain, any specific food item or a supplier.

Yum ‌Brands and Taylor Farms did not ​immediately respond to ⁠Reuters requests for comment. 

The Department of Health and Human Services, which oversees the U.S. Food and Drug Administration, did not immediately respond to a Reuters request for comment.

Separately, Bloomberg News reported that the U.S. FDA is expected ​to soon advise consumers to avoid shredded lettuce at Taco Bell restaurants in Michigan, Ohio, West Virginia, Kentucky and Indiana.

Cyclosporiasis can be contracted ‌by consuming food, typically raw fruits and vegetables or water contaminated with feces, ​and causes diarrhea, ​nausea and other gastrointestinal symptoms, Reuters reported.