The Detroit health department announced on Friday that two cases of the contagious liver disease have been linked to the health food store. The Detroit Free Press reports that an employee who worked in the prepared foods section and a customer who ate something from there have both been diagnosed with Hepatitis A. The health department is still uncertain how these people contracted the disease, and investigations are ongoing.

Whole Foods told the Detroit Free Press that after it had discovered an employees was diagnosed with Hepatitis A, “out of an abundance of caution, we immediately contacted the Detroit health department and began reviewing food logs and safety procedures.”

“While it remains unclear exactly how either of these individuals contracted Hepatitis A, and we know that Whole Foods Market Detroit has a comprehensive food safety protocol, we want to do our best to protect our residents and those of surrounding communities who may have been exposed,” Abdul El-Sayed, executive director of the Detroit health department, told the Detroit Free Press.

The health department has advised that any employees who handled any of the prepared foods between Oct. 6 and Oct. 12 consult a doctor for preventative treatment.

Whole Foods could not immediately be reached for comment.