Deadly Bacteria Found in Raw Pet Food. Again. Should We Be Worried? Hysterical? Or Just Plain Bored.

There was a small recall of raw pet food last week at Thorgersen’s Family Farm, one which I almost overlooked. 

Until I read the notice.

Something about this recall was different. Maybe it was the way they wrote about the danger of Listeria monocytgenes, how they laid bare the horrifying effects: fatal infections, stillbirths.

And it reminded me of the stories I had been reading lately, of the heartbreaking tragedies, and the shattering devastation of listeriosis; babies dying in their mother’s arms; mothers giving birth to premature and stillborn babies. 

It was the memory of those heart-rending stories that prompted me to look beyond this recall and examine the possibility – however remote – of a connection between raw pet food and human illness.

What I found was a complex and multilayered story populated by anxious veterinarians, concerned scientists, and nervous government officials. No one had a definitive answer, just the presumption that there is a possible connection between raw pet food and human illness.

However, slender the thread of a possible connection was, there was something they all agreed on: Raw meat is shitty.


Raw meat – whether intended for humans or pets – is very likely to be contaminated with all sorts of bacteria, mostly the kind of bacteria that comes from feces. Or what’s more commonly referred to in less academic circles as ‘bugs from shit.’

All raw meat is capable of harboring pathogenic bacteria belonging to the family Enterobacteriaceae—a bacteria that stems from fecal contamination – such as E. coli, Clostridium perfringens, Salmonella, Campylobacter including Listeria monocytogenes

I don’t think I’m overstating it when I say that the difference between the meat you buy for yourself and the meat you feed your pets is that there isn’t one.

They both contain shit.


However, there is a chance that the meat used in your pet food just may be a tad shittier than the meat you buy for yourself. That’s because raw meat and poultry used in pet food do not have to adhere to human food production standards. Therefore it is more likely to be contaminated and to be of inferior quality than meat destined for human consumption. And given that raw pet food is not designated for human consumption, the U.S. Food and Drug Administration does not require or uphold any specific meat inspection requirements or microbial testing for the manufacturing and storage of pet food.


There’s another difference between the meat you serve your family and the raw meat that’s destined for your pet’s bowl, and that is that you cook your meat, and you don’t cook your pet’s raw pet food.

So, even if you scrupulously scrub and disinfect everything meat touches in your kitchen, including your pet’s eating area and their bowls – your pets are still eating it raw. Which, for you, that may be an acceptable risk. Just as long as you understand, there is no such thing as sterile raw meat. And there’s still shit in it.


A scientist, Paul Overgaauw, a veterinarian at Utrecht University, did a study recently about raw pet foods that worried me.

It wasn’t the outcome of the study, which showed that nearly all of the raw pet foods he tested were contaminated with one zoonotic bacteria or another that surprised me, it was that he felt they could pose not only as a possible source of bacterial infections in pets, but if transmitted, could pose a risk for human beings.

It was his opinion, and many of his colleagues would agree with him that pets fed raw meat have significantly higher rates of shedding of potentially harmful bacteria.

However, the problem that he and his associates have in dampening consumers’ enthusiasm for raw pet food is that there is very little scientific evidence that shows that pets who shed pathogenic bacteria are capable of triggering disease in humans.


Short answer: Probably not. But, there is a possibility they could.

It’s like asking if you could be struck by lightning. Sure, it’s possible. Anything is possible.

Chances are greater though, if you stand in an open field during a thunderstorm holding a metal rod. So, I guess you could say that raw meat is the equivalent of that metal rod.

Whether you decide to take your chances, that’s up to you. But before you do, I would be remised if I didn’t explain how your pets might – I said might – make you sick.

Even though no one can definitively conclude there is a link between pathogens in pet food and human illness, scientists outline several ways in which pet owners and other household members can encounter such pathogens.

Scientists suggest that people come into contact with foodborne pathogens when they touch an infected pet. Other risks include allowing pets to give them slobbery kisses, handling contaminated pet food, touching any surface the contaminated food touched, by not being super scrupulous when cleaning up their poop, consuming food that has been cross-contaminated with disease-carrying pet food, and by coming in contact with a human of a pet who is infected with listeriosis.


Let’s take Lysteria, for example. When you refrigerate Listeria-contaminated food, the bacteria multiply even in cold temperatures, which, if you think about it, is pretty scary. So, if your Listeria contaminated pet food comes in contact with any other foods in the frig and contaminates those other foods – that would increase the likelihood that you and your pet could become ill.

But what about the rest of your house?

While it’s not realistic or even feasible to clean and disinfect every surface your pet comes in contact with, particularly if you are concerned about your pet shedding pathogenic bacteria, you might consider this:

When the Listeria bacteria get into your environment, it can live there for years.

Yeah, years.

And because of the hardiness of this bacteria, coupled with the high mortality rates, I worry.


Here’s the hard part.

I can’t give you any evidence that supports the link between human illness and pets because there is a lack of data on pathogen prevalence in the pets and on the incidence of human infections attributable to pets.

Human health risks from raw pet food (either from exposure to pathogens in the pet food or the poop of pets who eat contaminated food) are known to exist, but they’re not well characterized.

It is unclear whether contact with raw pet food is even considered in investigations of human illness, and most cases probably occur as sporadic infections, not outbreaks, which tend to get much more attention. We know this results in some degree of disease risk in animals and humans, but the scope of the problem is poorly understood.

I can’t even tell you how many pets get sick from food or any disease, for that matter.


Because the government doesn’t track foodborne illnesses in pets, so, we don’t know how often or how many pets get sick from eating pet food contaminated with pathogenic bacteria.

Ultimately, the real burden of illness associated with food-borne zoonoses is difficult to determine, due to the complex dynamic relationship between the host-pathogen and the environment.

In other words, we don’t know shit.


My argument today is not whether dogs and cats have a mechanism for handling pathogenic bacteria in their gastrointestinal tract. I’m not going there.

What I am talking about is the possibility that foodborne pathogens, like Listeria, are being spread in your house by the introduction of contaminated pet food.

Even if your dog or cat doesn’t get sick, they can become carriers of Listeria and transfer the bacteria to their surroundings and their environment.

In particular, I worry about the most vulnerable sectors of the population: pregnant women and their newborns, older adults, and people with weakened immunity who are especially susceptible to diseases like listeriosis.  I have the same concern for vulnerable pets like pregnant cats and dogs, newborn puppies and kittens, and old or sick pets.

Why do I worry? Because, historically, approximately one-half of babies infected in the womb or during delivery are stillborn or die as a result of the disease.

Make no mistake: Foodborne listeriosis is one of the most serious and most deadly of all foodborne diseases.


What are the actual odds of getting sick from casual food handling at home?

No one knows.

There are many variables involved, and only a small fraction of illnesses are reported, even to a family doctor. But one unambiguous and heartbreaking story can bring home the value of handling food carefully.

When I read those stories, I find it hard to support the idea that food contaminated with pathogenic bacteria poses no danger to pets or indeed to the people handling them. A more reasonable position, I suggest, is to assume that there is a risk and take the appropriate steps necessary to mitigate it.

If there is one thing, I hope you take away from this story, and that is that this is a tale of caution.


Raw Pet Food: The Problem That Just Won’t Go Away


Centers for Disease Control and Prevention. (2019). Listeria (Listeriosis). Available at

Damborg, P. et al. (2016). Bacterial Zoonoses Transmitted by Household Pets: State-of-the-Art and Future Perspectives for Targeted Research and Policy Actions.  Journal of Comparative Pathology. Available at

European Food Safety Authority. Listeria. Available at Food Poisoning: Listeria. Available at

Josefin, H. et al. (2019) Occurrence of Salmonella, Campylobacter, Clostridium, and Enterobacteriaceae in raw meat-based diets for dogs. Veterinary Record. Available at

Mayo Foundation for Medical Education and Research (2010). Listeria infection. Available at

National Institutes of Health, U.S. National Library of Medicine. (2019) Listeria Infections. Available at

Nemser, S., Doran, T., et al. (2014) Investigation of Listeria, Salmonella, and Toxigenic Escherichia coli in Various Pet Foods. Foodborne Pathogens and Disease. Available at

PennState Extension. (2016). Control of Listeria monocytogenes in Meat and Poultry. Available at:

Schlesinger, DP., & Joffe, D J. (2011). Raw food diets in companion animals: a critical review. The Canadian veterinary journal. Available at

United States Department of Agriculture. (2019) Listeria Monocytogenes; Policy, Procedures, Guidance. Available at

United States Food and Drug Administration. (2013). Keep Listeria Out of Your Kitchen. Available at

van Bree, FPJ. et al. (2018) Zoonotic bacteria and parasites found in raw meat-based diets for cats and dogs. Veterinary Record. Available at

World Health Organization. (2018). Listeria Fact Sheet. Available at

Weese, JS. (2011). Bacterial Enteritis in Dogs and Cats: Diagnosis, Therapy, and Zoonotic Potential. Veterinary Clinics of North America Small Animal Practice. Available at

Weese, JS. & Rousseau, J. (2006). Survival of Salmonella Copenhagen in food bowls following contamination with experimentally inoculated raw meat: Effects of time, cleaning, and disinfection. Canadian Veterinary Journal. Available at


I’m so glad you made it this far. Most people don’t read to the end. But you did, so that must mean you found this article informative and helpful. Either way, I’m glad you liked it. 
Now, I have a favor to ask. It’s not a big favor, but it’s an important one. But first I need to explain why I’m asking for it.
The advocacy work I do is unique in that it is funded by private individuals like you, not the pet food industry or any other private or public institution. Importantly, I do not sell, promote or otherwise endorse any pet products; and because I accept no advertising, I am entirely free from commercial influence.
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Mollie Morrissette

Mollie Morrissette, the author of Poisoned Pets, is an animal food safety expert and consumer advisor. Help support her work by making a donation today.

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