Now we can add dog food to the list of foods that can harbor Salmonella, a common cause of serious food poisoning. The Centers for Disease Control for the first time has attributed a large Salmonella outbreak to contaminated dry dog food. The link was discovered through an investigation of a large multi-state Salmonella outbreak that occurred between 2006-2007. The outbreak affected at least 70 people across 19 states. Many suffered serious illness and some were even hospitalized.

It's not clear how many of the cases were caused by eating the food and how many involved contamination of human food associated with handling the dog food. In any case, the incidents point to a need for greater pet food safety that goes beyond pet welfare alone. Pet food can potentially expose people to pathogens, both directly through pet food handling, and indirectly, through contact with pets. Because pet and human food production is sometimes linked (animal foods are sometimes made from wastes generated in human food production), pet food contamination may signal a larger problem that may affect the human food supply.

The pet food implicated in the outbreak—Krasdale Gravy dry dog food (5 pound bags) sold in Connecticut, Massachusetts, New Jersey, New York and Pennsylvania, and Red Flannel Large Breed Adult Formula dry dog food (50 pound bags) sold in Pennsylvania—was recalled in August 2007. Both brands were made by Mars Petcare. Though it's been nearly a year since the recall, it pays to check your pet food supply since some bags may still be on store shelves or stored in homes. 

Because pet food can harbor salmonella and possibly other pathogens, the CDC recommends that anyone handling pet food should take the same precautions needed when handling raw meat and chicken. Wash hands and all utensils and dishes with hot soapy water after feeding pets. Store dry pet food in a clearly marked container in a cool, dry place out of reach of children and away from areas where human food is prepared. Refrigerate wet food.

For  more information, read the CDC announcment and the FDA's FAQ on the recalled food.