ST. CHARLES, Ill. (WBBM) –Kane County health officials say eating at the Portillo’s Restaurant in St. Charles made at least 10 people ill over the past two weeks.

As WBBM Newsradio 780′s Bob Roberts reports, officials are still trying to determine the source.

LISTEN: Newsradio 780′s Bob Roberts reports

Although the strain is a rare one, 10 cases have been reported to west suburban health officials in the past two weeks. Most, or all, of those who took ill are believed to have eaten at the Portillo’s Restaurant in St. Charles.

The Portillo’s, at 3895 E. Main St., underwent a top-to-bottom cleaning overnight on Monday. Workers employed by the restaurant are not being allowed to return to their jobs until they receive negative results from two tests for the food-borne disease.

All food on hand in the restaurant until Monday either has been thrown out or removed to the health department for testing.

Asked if he considers the restaurant safe, Kane County Health Department Executive Director Paul Kuehnert said, “Absolutely.”

“If it wasn’t safe, we wouldn’t allow it to be open,” he said. “But they’ve taken every precaution and they have cooperated with us fully.”

The symptoms of salmonella include diarrhea, fever and abdominal cramps that begin within 12 to 72 hours of eating the spoiled food, and last for anywhere from four to seven days.

Kuehnert said that although most people recover without treatment or even visiting a doctor, the health department advises anyone who has had such symptoms to visit their doctors in order to assist investigators.