Federal health officials are investigating a multistate E. coli outbreak tied to raw milk cheese. The CDC and FDA say 13 people across nine states have fallen ill.

The outbreak is linked to Sierra Nevada Cheese Company’s Graziers grass-fed raw milk cheeses. Illnesses began between July 7 and August 26. Patients range in age from 1 to 58, with a median age of 5. More than half are children age 5 or younger.

Eight patients have been hospitalized. Three developed hemolytic uremic syndrome, a type of kidney failure. No deaths have been reported.

Of nine patients interviewed, all nine said they ate the Graziers raw milk cheese before getting sick. The FDA contacted the company on September 24. The company recalled all four Graziers raw milk cheeses the same day: medium cheddar, sharp cheddar, jalapeno jack and Monterey jack.

The CDC warns the cheese has a long shelf life. Anyone who has it at home should throw it out or return it. The true case count may be higher, since many people recover without testing.