SEATTLE — 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.

Six people in Washington, four in Idaho and four in Oregon have become sick, according to the CDC’s website. Utah says two people have become ill there. California and Missouri have each reported one sick person linked to the outbreak.

Two people have been hospitalized, although their location was unclear. No deaths have been reported.

The number of sick people is likely higher than the number reported, and the outbreak could extend to other states, CDC officials said.

The take-and-bake pizza company — based in Vancouver, Washington — has temporarily stopped selling their raw chocolate chip cookie dough and s’more bars dough. Although a picture of desserts, including cookies and s’more bars, could be seen on their website Tuesday, those items were not available to order.

People who have the dough in their homes should throw it away, and items and surfaces that may have touched the dough should be washed in the dishwasher or with hot, soapy water, according to the CDC.

Investigators are working to identify the contaminated ingredient in the raw cookie dough.

Most people infected with salmonella develop diarrhea, fever and stomach cramps six hours to six days after being exposed to the bacteria. The illness usually lasts four to seven days, and most people recover without treatment, according to the CDC.