Bert Kanist thought nothing of it when he gave his dog Ozzie a treat one day last month, peanut butter crackers.

Within a few hours, Ozzie was terribly sick.

He was vomiting, Kanist said outside his home in this suburb of Atlanta. He had diarrhea. His knees were wiggly.

The day after, Ozzie was dead. But Kanist’s other dog, Snickers a pound mutt, like Ozzie denied the crackers and was OK.

The crackers were from a brand called Austin, made by Kellogg Co. Kellogg recalled them in January because they were made with peanut paste manufactured by P.C.A. or Peanut Corp. of America of Lynchburg, Va., whose salmonella-contaminated products are blamed for making sick more than 500 persons and could possibly have contributed to at least eight deaths.

The Austin crackers were just one of more than 420 foods that companies across the food industry have recalled because they might be poisoned with salmonella, which most people probably think of as only a human pathogen.

But food safety professionals say pets can be equally at risk, either from eating tainted pet food or contaminated people food. That’s why at least fourteen brands of pet products are on the F.D.A.'s list of products that have been recalled since Jan. 1 because they were manufactured with products from Peanut Corp. of America.

From Owner To Dog And Back Again

As difficult as it may be to lose a beloved pet to salmonellosis, doctors say an infected pet poses a huge problem: It could infect its owner, because the bacterium Salmonella spp. can be transferred via urine, feces, or saliva.

That means you could get salmonellosis simply by allowing your dog lick you, veterinarians warn.

Even if their pets show no signs of the illness, owners should always be cautious. Researchers at the University of Wisconsin School of Veterinary Medicine said last year that they were able to easily isolate Salmonella spp. from healthy-looking dogs and cats, making them classic carrier animals.

Dogs and cats may suffer salmonellosis as a ‘reverse zoonosis,’ with infection transmitted from human-to-pet and subsequently back to other humans, the scientists wrote. Similarly, outbreaks of salmonella infections in large animal teaching hospitals have been linked to the introduction of bacteria from infected human employees, with subsequent spread to animals and then back to other human students.