A salmonella outbreak traced to jalapeño peppers imported from Mexico has spread to 27 U.S. states, sickening at least 345 people, the Centers for Disease Control and Prevention confirmed Thursday. The agency identified the contaminated peppers as the common source after epidemiological and traceback investigations pointed to Mexican-grown jalapeños distributed to restaurant chains and retailers nationwide.

The CDC linked the outbreak to jalapeños served at major fast-casual chains, including Chipotle and Qdoba. Both companies have been in contact with health officials and are cooperating with the investigation. It remains unclear whether the chains have removed the affected peppers from their supply chains or temporarily suspended their use at affected locations.

Salmonella infection typically causes diarrhea, fever, and stomach cramps beginning six hours to six days after exposure, with most people recovering without medical treatment within four to seven days. Hospitalization rates tend to be higher among young children, elderly individuals, and those with weakened immune systems. The CDC has not released a hospitalization count for this specific outbreak as of Thursday.

Investigators are working to identify the specific farms or distribution facilities in Mexico responsible for the contaminated peppers. The outbreak follows previous foodborne illness events tied to fresh produce imported from Mexico, including a 2008 salmonella outbreak initially attributed to tomatoes before jalapeños were identified as the source. Federal health and food safety agencies have not yet issued a formal recall, but consumers have been advised to monitor official guidance from the FDA and CDC as the investigation progresses.