Pet Food and Salmonella Poisoning

An interesting study was just published in Pediatrics, titled “Human Salmonella Infections Linked to Contaminated Dry Dog and Cat Food, 2006–2008.” This is important since roughly 1/3 of US households own cats and 1/3 of US households own dogs.

People tend to joke about the idea that “I’m from the government and I’m here to help.” In this case, that is true. A federal program called PulseNet helped identify this outbreak.

from Johansson et al. BMC Microbiology 2006 6:47

PulseNet is essentially a data warehouse where information is collected from pulsed field gel electrophoresis, which is commonly referred to as “DNA fingerprinting.” This process uses enzymes to cut apart DNA segments. These segments are placed in a gel and an electrical current is applied. These segments move at different speeds through the gel based on some of their physical characteristics. The idea is that two separate samples can be compared. If the patterns match, chances are that the samples came from the same strain of organism.

Without PulseNet, the chances of identifying the source of this outbreak (the pet food manufacturing plant) would have been challenging if not outright impossible. Sometimes your tax dollars are hard at work.

People typically associate salmonella with poultry and reptiles. However, as this study shows, there are other sources as well. The epidemiological data indicated that illness was primarily linked to children under two years of age, which makes sense because a lower dose of the organism is likely to cause disease.

The most interesting piece of this study though was that illness was also associated with pets being fed in the kitchen. The authors postulate that cross contamination played an important role. There was further evidence in that there were not cases reported among children who had put the pet food in their mouths. This seems to indicate that the contamination of other surfaces that were used for cooking allowed the bacteria to reproduce and have sufficient numbers to cause illness.

So what is the lesson from this? After you feed your pet, be sure to wash your hands. Good hygiene practices are once again the key to protecting you and your family from illness.

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