E. coli infections have been traced to Red Cow restaurants and Hen House Eatery in Minnesota

Ten cases of E. coli have been identified in customers who ate burgers at locations of the Red Cow restaurant chain, and one case was found at Hen House Eatery in downtown Minneapolis, the Minnesota Department of Health announced Friday.

The ground beef product linked to these infections was also distributed to other unidentified companies, according to the Department of Health. Additional cases could be identified from other locations and other possible cases were already being investigated.

Red Cow has a total of six locations in Minneapolis, St. Paul, Wayzata and Rochester.

According to the department, the confirmed cases refer to the meal dates of October 31 through November 7, and the onset of illness from November 4 to November 9. Those affected range in age from 9 to 70 years, and two of them have been hospitalized.

The owners of Red Cow and Hen House Eatery are fully cooperating with the investigation and have already implemented product changes to prevent further illness, the department said.

Symptoms of E. coli typically include stomach cramps and diarrhea, often with bloody stools. Illness can occur between one and eight days after exposure. About 5% of cases can lead to serious complications, such as acute renal failure.