Grappling with Salmonella


There have been numerous headlines recently regarding Salmonella in various types of pet food. Merrick Pet Care recalled one lot of its Doggie Wishbones — chews made of dried beef tendons. Two raw food producers – Bravo and Primal – had products recalled for Salmonella.  Then there were the pig ear incidents:  Bravo, Boss Pet, Blackman Industries, Keys Manufacturing, and Jones Natural Chews all announced recalls of dried pig ear chews due to Salmonella contamination. (I suspect strongly that after one company’s pig ears tested positive for Salmonella, the FDA started testing every pig ear chew they came across – and most are contaminated. Random tests for salmonella of dried meat chews are very likely to produce positive results – unless the products have been irradiated or treated in some other way to kill all bacteria.)

A tad more surprising were the recalls by Nestle Purina Petcare in June and July, for three different dry foods for adult cats. The mainstream pet food industry has tried for years to discredit raw diets by pointing out that raw foods frequently return positive tests for Salmonella – the “glass houses” analogy seems apt here. The industry has long promoted the myth that the high temperatures used to cook dry foods kill Salmonella and other pathogens, but since dry foods were rarely tested for the pathogen, it was rarely found. The more that dry foods are tested for Salmonella, the more it will be found. And it would appear that the FDA has been increasing its surveillance of the pathogen in pet food at the manufacturing level.

I doubt seriously that Salmonella is suddenly taking over the pet food industry – or even that it only recently invaded the human food supply. I think it’s been in the human food supply for decades – and of course, anything that’s in the human food supply will be present in greater amounts in pet food ingredients. The pet food industry receives most of its ingredients from the lower-quality castes of the human food supply. Anywhere the investigators look and test animal protein products in the mainstream commercial food industry, they will find Salmonella

Salmonella can be quite problematic for humans, but most dogs can ingest it without suffering any symptoms whatsoever. Theoretically, dogs with compromised immune systems are most at risk, but the fact is, Salmonellosis is rarely reported in dogs. The greater public health risk is for humans who may get sick from handling contaminated pet food.But how much of a risk is this, really? 

Interestingly, the FDA’s Center for Veterinary Medicine (CVM) just announced a “request for applications” from investigators who would like a grant to “evaluate potential risk of Salmonella-contaminated feeds on human and animal health by testing diagnostic samples from pets.” It would appear that now that they know it’s everywhere, they want to know what the scale of the risk actually is . . .

From the FDA CVM website:


In recent years, there have been an increasing number of human Salmonella outbreaks attributed to pet treats and pet foods. Salmonella infections can cause gastrointestinal disease in humans and animals. The occurrence of Salmonellosis in dogs and cats has not been adequately characterized. CVM is seeking applications that will provide information on the prevalence of Salmonella in fecal samples from both symptomatic and asymptomatic dogs and cats brought to veterinary clinics in order to gain further insight into the frequency of Salmonella infected companion animals. Bacteria will be isolated, identified and serotyped by the participating laboratories and the isolates will be submitted to FDA. Further DNA analysis will help CVM determine if the Salmonella strains isolated from pets are genetically similar to the strains previously isolated from humans or animal feeds. The data from this study will help CVM prioritize our investigations of foodborne diseases which adversely affect both animal and human health. The data will also help us rank future surveillance efforts.