The Illinois Dept. of Health is investigating 97 cases of Salmonella Hvittingfoss infection in 28 counties among people who ate at Subway sandwich restaurants in the state, Reuters reports. The Salmonella poisoning happened between May 11 and June 5, according to a state spokeswoman, and sent 26 people to hospital, but caused no deaths. The source of infection by this rare Salmonella strain has not yet been identified, but the restaurant chain voluntarily withdrew some items like onions, green peppers, tomatoes and lettuce in early June as a precaution. According to the U.S. Centers for Disease Control and Prevention, about 76 million people in the U.S. get sick each year from eating tainted food, and 5,000 people die. Subway didn’t return Reuters’ calls for comment.