Some 79 people in 21 states have been sickened with a bacterial infection linked to contaminated pet food — the first time human Salmonella enterica illness has been traced to a contaminated animal food plant.

None of the cases were fatal, and no pets became ill, according to this week's Morbidity and Mortality Weekly Report.

The manufacturer of the dry dog and cat chow food linked to the outbreak, Mars Petcare US, recalled the 105 products in September and closed its Everson, Pa., factory where the tainted kibble was made, Centers for Disease Control and Prevention (CDC) scientists say. But they warn that some of the food may still be on consumers' shelves and shouldn't be fed to pets. Among the tainted brands: Pedigree, Country Acres, 'Ol Roy and Paws & Claws.

Seventy of the Salmonella infections, which can cause stomach upset and pain, vomiting, fever and lethargy, occurred between 2006 and 2007, according to health officials. But another nine have turned up since in Pennsylvania, Georgia, Texas and New York, the last one in September, the CDC says. Most were in children under age 2.

The bacteria could have spread if the food came in contact with kitchenware or with children whose immune systems are more easily attacked by weak strains of germs, the scientists say.
 
On Oct. 27, Mars Petcare recalled its dry Special Kitty brand gourmet blend in 15 states as a precaution even though it hasn't been linked to any illnesses, according to the company's Web site. Consumers who still have the chow can return it to the store where they bought it for a refund.

In the past three years, companies have recalled at least 135 pet products, including food and supplements, because of Salmonella contamination. No people got sick from those products, the CDC says. (It's not clear from the MMWR if animals were infected from those foods, and the Food and Drug Administration didn’t immediately return a call seeking more information. Pets can suffer from the same Salmonella symptoms as humans, and owners of animals that have eaten contaminated products and appear sick should contact their veterinarians.)

"We have not resumed production at the [Everson] facility, and we have no plans to do so out of a commitment to the safety of our pet owners and their pets," the company said in a statement. "Mars Petcare US remains committed to working with the FDA and all stakeholders who share our goal of ensuring the safety of pet food products."

An estimated 8,500 cats and dogs got sick and hundreds died last year after eating pet food contaminated with melamine, a nitrogen-based compound used in plastics that Chinese companies were found to be using to artificially inflate supposed protein levels in the pet fare. Tens of thousands of babies in China have been sickened by melamine-contaminated food this year, and a handful have died.

(Updated at 2 p.m. Nov. 7 with comment from Mars Petcare US.)

(Image by iStockphoto/Luis Carlos Torres)