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

The ground beef product connected to those infections was also distributed to other unidentified establishments, according to the Health Department. Additional cases from other locations could be identified, and other potential cases were already under investigation.

The confirmed cases involve meal dates from Oct. 31 through Nov. 7, and illness onset dates from Nov. 4 through Nov. 9, according to the department. Those affected range in age from 9 to 70 years, and two of them have been hospitalized.

Red Cow and Hen House Eatery owners are fully cooperating with the investigation and have already made product changes to prevent further illness, the department said. Red Cow has a total of six locations in Minneapolis, St. Paul, Wayzata and Rochester.

Symptoms of E. coli typically include stomach cramps and diarrhea, often with bloody stools. Illness can set in anywhere from one to eight days after exposure. About 5% of cases can lead to severe complications such as acute kidney failure.