Mexico’s health and agricultural ministries announced they ‌are investigating a large outbreak of a foodborne illness in the U.S. linked to iceberg lettuce grown in Mexico and sold at Taco Bell.

Cofepris, Mexico’s sanitary regulator, and Senasica, the country’s agricultural and food safety regulator, said in a statement ‌Friday that they have an interagency technical working group ​investigating the matter and adopting preventive measures.

The group has undertaken inspections and traceability analyzes that “are strictly preventive in nature” ⁠and “aimed at mitigating any potential health risk,” the agencies said.

The CDC ​has reported around 100 hospitalizations of people becoming sick with cyclosporiasis, ⁠a parasitic infection that can cause severe diarrhea and other gastrointestinal symptoms, after eating shredded lettuce at Taco Bell restaurants in Indiana, Kentucky, Michigan, Ohio and West Virginia.

On Friday, ‌Taylor Farms, a California-based lettuce supplier, and food distributor Sysco, ​America’s largest, said they ‌are removing iceberg lettuce sourced from central Mexico, based on information provided by the U.S. ‌Food and Drug Administration (FDA).

An industry source who requested anonymity because they were not authorized to speak to the media told Reuters that the lettuce ⁠was produced as 5-pound (2.3-kg) bags ‌at Taylor Farms' facility ⁠in Guanajuato, in central Mexico. The source also said that Sysco widely distributes such ⁠bags to ⁠hospitals, ball parks and fast-food chains.

Mexico’s health and agricultural ministries cautioned in their statement that "the investigation ‌remains ongoing, and it is important to emphasize that identifying a product's country of origin through traceability does not, by itself, confirm that contamination occurred in ‌Mexico."

Taylor Farms' ​growing and processing ‌facilities in Mexico were the source of another major U.S. cyclosporiasis outbreak. A 2013 outbreak sickened more than 600 people in ​25 states, according to the CDC, and was traced to salad mix from Taylor Farms de Mexico in Guanajuato.