Whole Foods Market Inc. shares declined as much as 2.5 percent after the Detroit Health Department said its investigating two cases of hepatitis A that may be connected to one of the chains stores.

One of the cases was an employee who handles prepared food at the store, which is located on 115 Mack Ave., the agency said in a statement on Thursday. The other person sickened was a customer who ate from that section of Whole Foods, the health department said.

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, the agencys executive director and health officer, said in the statement. Whole Foods has been nothing but cooperative throughout this process.

The news jarred investors, sending the stock as low as $28.01 in New York trading. Whole Foods shares have already been battered this year, hurt by concerns that the organic-food grocer is losing ground to mainstream supermarkets and faces slowing growth. The stock was down 14 percent this year through Wednesdays close.

Liver Disease

Hepatitis A, a liver disease, is typically spread by contaminated food or drink. It can cause fever, diarrhea and vomiting, as well as turn the victims eyes and skin yellow. There were three outbreaks of the disease last year, resulting in 13 illnesses and five hospitalizations, according to the U.S. Centers for Disease Control and Prevention.

The Detroit Health Department recommends that anyone who ate prepared foods from that Whole Foods between Oct. 6 and Oct. 12 seek treatment from a physician.

Whole Foods, based in Austin, Texas, said the store was following all its food-safety protocols and that the company contacted health officials out of an abundance of caution. After the employee was diagnosed, Whole Foods said it immediately began reviewing food logs and procedures.

While there is no definitive link that the second case is related to the occurrence in our store, we are cooperating fully with the Detroit Health Department to ensure the safety of our customers and team members, the company said in a statement.

Earlier this year, Whole Foods was cited by the U.S. Food and Drug Administration for unsanitary conditions at a plant in Everett, Massachusetts. That facility supplies prepared foods and other products to dozens of Whole Foods stores in the Northeast.

Read more: http://www.bloomberg.com//news/articles/2016-10-20/whole-foods-declines-after-hepatitis-linked-to-store-in-detroit