The Centers for Disease Control and Prevention, along with state and federal agencies, are investigating reports of 18 salmonella infections in at least half a dozen states that may have come from raw cookie dough sold at Papa Murphy’s.

People have been sickened in Washington, Oregon, Idaho, Utah, California and Missouri, the CDC said Tuesday. Illnesses were reported from Feb. 27 to May 2.

Interviews with sick people show that raw cookie dough sold at Papa Murphy’s Take ‘N’ Bake pizza stores may be contaminated. People reported eating the cookie dough raw, the CDC said.