The U.S. Centers for Disease Control and Prevention said that the salmonella infections from contaminated dry pet food that sickened at least 79 people could be dangerous. The suspected salmonella infection from a pet food plant in Pennsylvania has prompted the closure of the plant and a recall of the affected brands.

The salmonella outbreak is of a rare strain known as Salmonella enterica serotype Schwarzengrund, the CDC said, which causes bloody diarrhea and can make pet food handlers, especially the very young and very old sick.

The CDC said today in the Nov 7 issue of Morbidity and Mortality Weekly Report that 79 cases since 2006 have been identified in humans though no pets have reported sickened. The CDC said, "Dry pet food has a 1-year shelf life. Contaminated products identified in recalls might still be in the homes of purchasers and could cause illness. Persons who have these products should not use them to feed their pets but should discard them or return them to the store."

The CDC report said the salmonella cases are linked to pet food from a Mars Petcare US facility in Everson, Pa., which included Special Kitty, Pedigree and Member's Mark, and a nationwide recall was issued in September. The plant was closed for cleaning and renovation from July until mid-November of 2007 and the company recalled all dry dog and cat food products made at the plant from Feb 18 through Jul 29, amounting to more than 23,000 tons, according to the CDC.

After more outbreaks occurred an announcement was made in October that the plant would be permanently closed.

The eight cases included three in Pennsylvania, two in Georgia, two in New York, and one in Texas. Six of the patients were 2 years old or younger. Six of the eight patients' households had pets (pet ownership status for the other two was not known), but none of the pets had been sick, the CDC reported. Three households used brands of pet food made at the Everson plant, but it could not be determined whether any of the food had actually come from that plant.

The report added, "Consumers and health departments should be aware that all dry pet food, pet treats, and pet supplements might be contaminated with pathogens such as Salmonella, and consumers should use precautions with all brands of dry pet food, treats, and supplements."

"In contrast, canned pet food is unlikely to be contaminated with such pathogens because the manufacturing process should eliminate bacterial contamination."

People should wash their hands with water and soap for at least 20 seconds after handling these products, and especially before handling human food. Children under age 5 should not be allowed to touch or eat dry pet food.