The Raw Deal

I have avoided writing this essay.

The reason is that, contrary to how it may on occasion appear, I generally do not seek out conflict. Considered debate about scientific evidence and civilized discussions? Yep, enjoy those. However, the acrimony and polarization that frequently accompanies internet discussions about how best to feed dogs? Avoid those like the plague.

But, here’s the thing. I write about dogs and science. Over the last year or so, the number of published scientific studies that examine a particular aspect of raw feeding have continued to accumulate on my desk. I read them, sigh, and place them back on the pile.

My aversion to internet fighting was proving to be greater than my need to write science.


On my desk are three new studies, all in refereed, academic journals, and all reporting about the presence of pathogenic bacterial and parasitic contamination in commercially-produced raw dog foods.


Here is what they say:

Study 1: Dutch epidemiologists with the Division of Veterinary Public Health in Utrecht, Netherlands, tested 35 commercial raw, meat-based diets (hereafter, RMBDs) for the presence of bacterial and parasitic pathogens (1). The researchers purposely selected popular brands that were sold by retailers. All of the samples had been stored according to label recommendations prior to analysis. Results: Escherichia coli (E coli) was found in 30 products (86 %). Twenty-eight foods contained an antibiotic-resistant strain of this microbe and eight were contaminated with a strain that causes serious illness in humans. Listeria species were found in 43 % and Salmonella species were found in 20 % of the tested foods. Several products were contaminated with parasites, but this risk was substantially lower than that of bacterial contamination. Conclusions: Because several of the pathogens that were isolated were zoonotic (i.e. are pathogenic to humans) and because the transmission of antibiotic-resistant bacterial strains is an increasingly serious public health issue, the authors conclude that pet owners should be informed of the potential health risks (to humans and to pets) associated with feeding RMBDs.

Study 2: Although conducted in pet cats rather than dogs, this study is important because it examines the effects of feeding a raw diet on changes in fecal bacterial populations and the potential for exposure to antibiotic-resistant microbes (2). The study enrolled 17 pet cats that were fed dry, extruded cat food or a combination of dry food and canned food (the control group), and 19 cats that were fed a frozen or fresh raw diet. Fecal samples were collected weekly and were analyzed for the presence of antibiotic-resistant forms of species within the intestinal bacteria family of Enterobacteriaceae. In addition, 53 cat foods (18 raw products and 35 dry or canned products) were analyzed for the presence of the same bacteria. Results: In the control group (cats that were not fed a raw diet), 3 of 51 samples (5.9 %) were positive for the presence of antibiotic-resistant microbes. In the raw-fed group, 37 of 57 samples (65 %), collected from 17 of the 19 cats, were positive for antibiotic-resistant bacteria. When present, the concentration of these microbes was also found to be significantly higher in cats fed raw diets. Finally, 77.8 % of the raw foods and 0 % (none) of the cooked foods were found to be contaminated with antibiotic-resistant bacteria. Conclusions: This study found a strong association between feeding cats a raw diet and fecal shedding of antibiotic-resistant bacteria. This association suggests a substantial risk of transmission of antibiotic-resistant bacteria to both the animals and to the owners who handle these foods and who may also be exposed to their pet’s fecal matter.

Study 3: In this study, samples of 60 commercially available, frozen RMBDs were tested for microbial contamination (3). Results: Bacteria of the taxonomic family Enterobacteriaceae were found in all 60 samples (100 %). In half of these (52 %), the concentration exceeded the threshold level considered acceptable by EU regulations. Clostrium perfringens was detected in 18 brands (30 %) and concentrations exceeded the maximum allowed in two brands. Salmonella species were found in 4 samples and Camplylobacter species were isolated in three samples. Conclusions: Like other authors, the researchers recommend that pet owners are informed about the pathogen risks associated with raw feeding. They also go a bit further, stating that in view of the antibiotic-resistance problem, dogs who are being treated with antimicrobials should not be fed raw diets; nor should dogs living in homes with infants, elderly people or immunocompromised individuals because these subgroups are more vulnerable to infection.

Review Study (March, 2019): This is the most recently published paper (4). The authors review more than 30 scientific studies, published in academic journals between 2005 and 2019, that measured bacterial pathogens in raw pet foods. In both Europe and the United States, a high proportion of the tested foods had contamination levels that exceeded the minimum acceptable levels for human meat products. The most commonly isolated pathogens were Salmonella and E coli. Most recently, antimicrobial-resistant forms of several different bacterial species have been reported. Conclusions: The authors conclude that there remains little doubt, based upon the published evidence, that the prevalence of potentially serious pathogens is substantially higher in raw pet food than in heat-treated foods and that these levels may pose a significant health risk to both pets and humans.

The (Raw) Deal: As it stands today, the research evidence regarding benefits and risks associated with feeding raw diets tells us this:

  • Health benefits? As with any broad category of feeding, the long-term health benefits of feeding raw foods to dogs is difficult to study. To date, most of the purported advantages of feeding raw are based on personal stories and anecdotes and do not have support from controlled feeding trials. The few feeding trials that have examined general health have reported that dogs fed a nutritionally balanced raw diet remain healthy, but have not demonstrated enhanced health benefits above those of dogs fed other foods. This does not mean that there are no benefits; it simply means that we do not know and that the numerous health claims for raw foods are not based on scientific evidence.
  • Improved digestibility and nutrient availability? Some owners select a raw food for their dog because they are interested in feeding less highly processed foods. In the dog food realm, both dry, extruded food (kibbles) and canned foods are highly processed and are almost exclusively produced from non-human grade (i.e. “inedible”) ingredients. The way in which these ingredients are handled and cooked during processing causes moderate to severe changes in protein quality and the loss of some nutrients. Therefore, it is not surprising to find that raw diets are usually higher in digestibility than processed foods. However, both digestibility and nutrient availability are dependent upon the quality of the starting ingredients, as demonstrated by a recent study of raw versus processed chicken. There is also evidence, from several researchers, that raw feeding alters intestinal microbe populations. What is not known however, is the impact, if any, of these changes upon digestive capacity or health.
  • Safety? The studies reported in this essay provide evidence that commercial raw dog foods are more likely to be contaminated with bacterial pathogens and with specific strains of these pathogens that are resistant to antibiotics. These results show that dogs and people may be at risk of infection and that these foods are a potential vector for the spread of antibiotic-resistant strains of bacteria to other animals and people. 

My intention with this essay was not to start an internet fight.  

However, the research says what it says. And currently, there are numerous studies, from different, unrelated laboratories, showing us that commercial raw diets are more apt to be contaminated with potentially harmful bacteria.

This is the science.

Deal with it: If you are a raw feeder, then deal with this information in the smart way. Ask producers about their methods for controlling bacterial contamination, about their quality control measures, and about their company’s recall history. Select foods that have been shown to be free of pathogenic bacteria and have not been recalled. When feeding, avoid handling raw products, wash your hands and food preparation surfaces thoroughly, and monitor your dog carefully for signs of illness or gastrointestinal infection.

The science tells you that these are the facts. It is your decision regarding how to deal with them. 

Cited Studies:

  1. van Bree FPJ, Bokken G, Mineur R, et al. Zoonotic bacteria and parasites found in raw meat-based diets for cats and dogs. Veterinary Record 2017; November: doi: 10.1136/vr.104535.
  2. Baede VO, Broens EM, Spaninks MR, et al. Raw pet food as a risk factor for shedding of extended-spectrum beta-lactamase-producing Enterobacteriaceiae in household cats. PLoS One 2017; November:
  3. Hellgren J, Hasto LS, Wikstrom C, Fernstrom LL, Hansson I. Occurrence of Salmonella, Campylobacter, Clostridium and Enterobacteriaceae in raw meat-based diets for dogs. Veterinary Record 2019; March: doi:10.1136/vr.105199.
  4. Davies Rh, Lawes JR, Wales AD. Raw diets for dogs and cats: A review, with particular reference to microbiological hazards. Journal of Small Animal Practice 2019; March:doi.10.1111/jsap.12300.

Interested in Learning More about Canine Nutrition? Take a Look at the New Science Dog Courses!

Interested in learning more about how to critically evaluate and select the best food for your dog? Read Linda Case’s best selling book, “Dog Food Logic: Making Smart Decisions for Your Dog in an Age of Too Many Choices“.

69 thoughts on “The Raw Deal

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  5. I love your articles! Some times they are a little long to read before getting to the point, but I save them a PDF’s and save them for later review- The sad part is that I can’t find a simple answer and move on to another subject like desert! My dog, a small 4 pound poodle and at 14 yrs old developed kidney disease or so it’s said- with a high BUN reading from her blood test I guess that would be an indication- My issue is she hates (won’t eat) the KD food and when I look up how to deal with this there are too many options- Raw, Not raw, eggs- dry, canned-
    My issue is, if my pup won’t eat her special vet approved should I choose between high nitrogen levels or just plain old starvation?
    She was never a good eater and always was very boney and thin- but at 14 I’m assuming that is her nature- I mean in real life there are people who never put on an ounce and others who pork up with the thought of food-
    I decided to walk the line and offer a bit of both- semi cooked raw, canned and dry and dry wetted town with home make chicken broth or tuna-
    I hope I’m not making a mistake, but with all of the conflicting expert advice available, I let “Nooch make the dietary decisions by offering a small buffet and backing up with some oral vitamins each night-


    • Hi Richard, Thank you for your note. I am so sorry to hear that your girl has been diagnosed with Renal Disease. Regarding diet: it is not unusual at all for dogs with chronic renal disease and elevated BUN and creatinine levels to refuse to eat a prescribed commercial veterinary diet. Because of this, we usually recommend that owners use a homemade food (with human grade ingredients) using a recipe that is formulated by a veterinary nutritionists. Using this type of recipe will allow you to feed a reduced protein diet that will help to reduce your girl’s BUN levels (and hopefully to manage her clinical symptoms), slow progression of disease, and hopefully improve her quality of life. The two services that we recommend for these recipes are either Dr. Rebecca Remillard at or the group of nutritionists at BalanceIT. Both groups are able to provide recipes for renal disease (but may require going through your veterinarian – you should inquire about this with them). Here are their websites, fyi, if you are interested in trying this approach: and

      Good luck with Nooch – she is lucky to have you as her human caretaker.

      Best wishes, Linda Case


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  7. Somehow I missed this article. Great article on insects! I have been feeding my dogs raw for 2 years now without incident. I source my food from local, mostly organic farmers, and am very careful handling and cleaning. My motivation is that I really care about what they (and us) consume. I love to cook but and am interested in making cooked food for them but what about the bones? RMBs are a good portion of their diet, and I’ve always heard that cooked poultry bones etc are dangerous. I do make bone broth for them but discard any bones that I can’t pulverize.


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  9. Thanks for this article! I’m happy to say my (small, local) raw food provider regularly tests their food and it always exceeds standards for human products, and my dogs are thriving on it. I have a couple of thoughts. One is what is the incidence of pathology(raw food related infectious disease for example) in families where their dogs are raw fed, compared to families where dogs are fed non raw food? Also, what is the incidence of bacterial or other contamination of kibble type foods? There are no risk free foods. Just different risks and varying tolerance and perception of those risks. Also, who is the sponsor of the studies(because I am cynical. I work in medicine and am aware of many studies published by those with an agenda)


  10. Informative, but not completely surprising since even raw foods we cook for ourselves are contaminated. It would have been even better if the bioavailability of the nutrition in the diets were tested on both products—to see whether it’s even worth the risk of feeding raw. However, my question lies with air dried raw and freeze dried raw. Have they done any studies with those? Supposedly (according to the labels), one “raw” dog food’s air drying system and a few freeze dried foods solve this issue. Do you have any science based information on this? Thank you!


  11. I would also love to know if there is any information on the pathogenic load in freeze-dried/dehydrated foods, which are becoming more popular and are very convenient.


  12. Many thanks for this informative article. I have a question about the ‘safety’ aspect. In your summary you say, ‘The studies reported in this essay provide evidence that commercial raw dog foods are more likely to be contaminated …’ Presumably more likely than kibble? But there is no mention of the researchers testing kibble (in studies 1 & 3) so how can they draw these conclusions? I’ve read on other sites that there have been many more recalls for kibble than for raw over the years. e.g Data from the FDA reports that 149,948,840lbs of kibble was recalled between 2012-2019, compared with only 1,986,035lbs of raw. But I note that it’s comparing number of pounds and not number of products, so perhaps that distorts the message? I really don’t know! I so want to understand the facts, but they are so conflicting! 😫


  13. Thank you for publishing this article, it was shared through a fb group I’m in but I purposely took to read it outside of fb because of the increased levels of adversity I’m seeing, as raw feeders can be a very cutthroat group of people. I’ll need to research further however when you say gently cook to 1600° is that applicable to none in blends? I’d gather they’re not safe when cooked. And what about rmb’s, are they completely to be avoided with this line of thinking? I do worry about the levels of bacteria present and feed a mix of premade as well as diy human grade food. Of course only wanting what’s best for my hearts while not wanting to cause any negative external impacts.


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