The Madison County Health Department is investigating how 13 people recently received salmonella from an East Alton restaurant.

The customers reported illnesses after they ate at Casa Romero Restaurant. No one has suffered severe illness. The restaurant, which voluntarily closed last week, will reopen after the investigation is completed, said Toni Corona, county public health administrator.

The county received the first reported case of salmonella from the restaurant on June 2.  The health department is now trying to determine the source of the salmonella bacteria. The county is currently interviewing past patrons, employees and others affiliated with the restaurant.