The Subway sandwich chain has apologized for a Salmonella outbreak in central Illinois that has sickened nearly 100 people ages 2 to 79, Reuters reports. The company said it is working with public health officials to pinpoint the source of the contamination.

The Illinois Department of Health has confirmed 97 cases of Salmonella Hvittingfoss infection from 28 Illinois counties linked to 47 Subway restaurants. The source of the rare strain is still unknown, but Subway has voluntarily pulled tomatoes, onions, green peppers and lettuce from its Illinois restaurants as a precaution. More gruesome details after the jump.

All of the cases were linked to dining at Subway restaurants between May 11 and June 5. More than two dozen people were hospitalized but all recovered, public health officials say. At least one lawsuit against the chain has already been filed, according to the Food Poison Journal.

Most consumers infected with Salmonella will experience moderate symptoms, much like the stomach flu. Others may experience more severe bouts of diarrhea or vomiting and require hospitalization for dehydration.

“We are truly sorry for the difficulty this situation has caused you, our customer, and are working diligently to solve this mystery and to regain your trust,” Subway, one of the largest U.S. restaurant chains, said in a statement. “We are confident the current fresh produce being served in Subway restaurants are safe to eat,” the company added.

Subway has more than 28,500 locations in 86 countries. No illnesses have been linked to Subways in California.

LA Weekly