Salad Identified as Possible Source of Salmonella Outbreak Linked to St. Charles Portillo's

Salad is thought to be the possible source of contamination that led to a recent outbreak of a , according to Kane County Health Department officials.

The health department is reporting 15 confirmed cases of , the majority of which appear linked to Portillo's in St. Charles. Eleven of the people infected ate at the restaurant and seven of them reported eating salad.

The exact cause of the contamination has yet to be determined.

“Our investigation is showing that the outbreak appears to be localized,” said Kane County Health Department Executive Director Paul Kuehnert in a media release. “We want to thank Portillo’s, as it has cooperated thoroughly and proved to be an active partner in this investigation.”

On Monday, the health department released information on the infected people: eight are from Kane County, four are from DuPage County, one is from Chicago, another is from DeKalb County and remaining one reportedly lives in Minnesota.

Two Portillo's employees tested positive for the particular strain of salmonella but are believed to be victims, and not causes, of the outbreak, according to county health officials. 

The onset of the disease was April 5-30. Three of the victims were hospitalized. Ten of the infected were female (their ages weren't immediately available).

According to the health department, 76 employees were cleared to return to work and have twice tested negative for the virus. Food samples from the restaurant also reportedly came back negative.

The county health department , as well as the Illinois Department of Public Health and DuPage, DeKalb and Chicago health departments, continue to investigate the outbreak.

Most people with salmonella will develop diarrhea, fever and abdominal cramps with 72 hours after being infected, according to the health department. The illness can last up to seven days.

The health department is recommending that anyone who ate at the St. Charles Portillo's between April 5 and May 6, or who has these symptoms right now, contact them at 847-608-2128.