MINNEAPOLIS (WCCO) — Two Burger King restaurants in Bemidji have been forced to shut their doors following a salmonella outbreak.

The Minnesota Health Department tells the Star Tribune that since September, they’ve confirmed 27 cases of salmonella linked to the two fast-food restaurants.

Officials say there are four other possible cases.

Both of the Burger King locations closed voluntarily Thursday to undergo a thorough decontamination process.