(CNN) The CDC and the FDA are investigating an outbreak of salmonella linked to contact with pig ear dog treats.
Forty-five people across California, Illinois, Indiana, Iowa, Kansas, Massachusetts, Michigan, Missouri, New York, North Dakota, Pennsylvania, South Carolina and Wisconsin have been infected. Twelve have been hospitalized.
Officials from the Michigan Department of Agriculture and Rural Development sampled the pig ears for salmonella.
They have identified some strains in the treats, but it is unclear whether those are the same strains causing the infection.
The CDC recommends that people always wash hands when handling pet food or treats, store pet food away from human food, and never let pets lick mouths, faces or open wounds.