Salmonella and Other Risks of Raw Pet Diets

Primal Pet Foods, a popular marketer of commercial raw diets for dogs and cats, recently announced a recall of one of its raw cat foods because testing has suggested the diet may be contaminated with the bacteria Salmonella. Such recalls in the pet food industry are typically precautionary, and most of the time no actual harm results for pets or their owners. Nevertheless, since advocates of homemade and raw diets tend to promote such recalls as evidence of the unhealthy nature of conventional commercial pet diets, and to try and equate every recall with the tragic, but unusual, melamine contamination problem of 2007, I feel it is important to point out that raw diet and other pet products touted as “natural” and healthy are also subject to such recalls.

Whether or not this particular diet turns out to be source of disease for pets or their owners is less important than the general health risks posed by raw pet diets. I have discussed these diets at length before (e.g. here and here), and the bottom line is this:

1) The theoretical arguments used to promote them are not sound.

2) There is no evidence for the supposed health benefits claimed for raw diets or for most of the health hazards raw diet advocates claim are associated with conventional pet foods.

3) The risks of raw diets are probably small but certainly greater than those for conventional foods, without any apparent benefits to justify them.

These conclusions are much the same as those in a research review being presented next week at the annual meeting of the American College of Veterinary Internal Medicine. Dr. Anread Fascetti, a board-certified veterinary internist and nutritionist, reviews the literature concerning raw diets (1), and finds a number of serious concerns.

A. Nutritional Inadequacy:
A number of studies of both commercial and homemade raw diets have found significant nutritional deficiencies or excesses (2, 3). In one study, cats fed a diet based on raw rabbits developed heart muscle disease associated with a deficiency of the amino acid taurine (4).

B. Lack of Health Benefits:
The little research that has been done on raw diets does not support dramatic claims of health benefits. Some research has found subjective differences in coat and stool quality but not in any other factors evaluated (4). One study suggested that periodontal disease was reduced by adding oxtail to the diet, but other studies have found high rates of periodontal disease in wild dogs and feral cats consuming whole prey (5, 6), and no difference in oral health between domestic cats eating commercial diets or mostly whole prey (7).

C. Health Risks:
As I have pointed out before, raw diets are more likely than cooked diets to be contaminated with infectious organisms, including Salmonella. Such organisms have been found in raw diets (1, 8-12) and have been found shed in the feces of pets eating these diets (13), they can be passed from pets to humans (13-16), and they have caused illness in both pets and humans (16-18).

Another recent paper in the Journal of the American Veterinary Medical Association, written by Dr. Kate KuKanich (19), specifically addresses the subject of Salmonella contamination in pet foods and treats. Her analysis of the literature shows that uncooked foods and treats are far more likely to be contaminated with Salmonella, and that up to 69% of sled dogs and 61% of racing greyhounds fed raw meat shed this organism in their feces even when they have no diarrhea or other clinical symptoms. This is compared to a rate of shedding of less than 5% up to 15% in studies of other healthy dogs. While Salmonella contamination after cooking has been found in dry diets, the risks for uncooked foods and treats are substantially higher, and Dr. KuKanich concludes, as I would,

Ample evidence exists for the risk of Salmonella contamination in raw food diets; thus, it is advised that pet owners avoid feeding raw food diets to pets.

 

References
1. Fascetti AJ. Raw food diets: A research review. Proceedings, American College of Veterinary Internal Medicine Forum, Denver, CO, June 15-18, 2011.

2. Freeman L., Michel, K., Nutritional analysis of 5 types of “Raw Food Diets.”  JAVMA March, 2001;218(5): 705.

3. Dillitzer, N, Becker, N, Kienzle, E. Frequency and extent of nutritional imbalances in “bone and Raw food” (barf) rations. Proceedings Waltham Interational Nutritional Sciences Symposium, Cambridge, UK, September 16-18, 2010. p. 44.

4. Glasgow AG, et. al. Role of Diet in the Health of the Feline Intestinal Tract And in Inflammatory Bowel Disease. Center for Companion Animal Health, School of Veterinary Medicine, University of California at Davis. Accessed June 5, 2011 at http://www.vetmed.ucdavis.edu/ccah/local-assets/pdfs/Role_of_diet_feline%20health_Glasgow.pdf

5. Steenkamp G, Gorrel C. Oral and dental conditions in adult African wild dog skulls: a preliminary report. Journal of  Veterinary Dentistry. 1999 Jun;16(2):65-8.

6. Verstraete FJ, van Aarde RJ, Nieuwoudt BA, Mauer E, Kass PH. The dental pathology of feral cats on Marion Island, part II: periodontitis, external odontoclastic resorption lesions and mandibular thickening. Journal of Comparative Pathology. 1996 Oct;115(3):283-97.

7. Clarke DE, Cameron A. Relationship between diet, dental calculus and periodontal disease in domestic and feral cats in Australia. Australian Veterinary Journal. 1998 Oct;76(10):690-3.

8. Chengappa MM, Staats J, Oberst RD, Gabbert NH, McVey S. Prevalence of Salmonella in raw meat used in diets of racing greyhounds. Journal of Veterinary Diagnostic Investigations. 1993 Jul;5(3):372-7.

9. Joffe DJ, Schlesinger DP. Preliminary assessment of the risk of Salmonella infection in dogs fed raw chicken diets. Canadian Veterinary Journal. 2002 Jun;43(6):441-2.

10. Weese JS, Rousseau J, Arroyo L. Bacteriological evaluation of commercial canine and feline raw diets. Canadian Veterinary Journal. 2005 Jun;46(6):513-6.

11. Morley PS, Strohmeyer RA, Tankson JD, Hyatt DR, Dargatz DA, Fedorka-Cray PJ. Evaluation of the association between feeding raw meat and Salmonella enterica infections at a Greyhound breeding facility. Journal of the American Veterinary Medical Association. 2006 May 15;228(10):1524-32.

12. Leonard EK, Pearl DL, Finley RL, Janecko N, Peregrine AS, Reid-Smith RJ, Weese JS. Evaluation of pet-related management factors and the risk of Salmonella spp. carriage in pet dogs from volunteer households in Ontario (2005-2006). Zoonoses Public Health. 2011 Mar;58(2):140-9. doi: 10.1111/j.1863-2378.2009.01320.x.

13. Finley, R. et al. The risk of Salmonella shedding by dogs fed Salmonella-contaminated commercial raw food diets. Canadian Veterinary Journal. 2007;8:69-75.

14. Gutman LT, Ottesen EA, Quan TJ, Noce PS, Katz SL. An inter-familial outbreak of Yersinia enterocolitica enteritis. New England Journal of Medicine. 1973 Jun 28;288(26):1372-7.

15. Morse EV, Duncan MA, Estep DA, Riggs WA, Blackburn BO. Canine salmonellosis: A review and report of dog to child transmission of Salmonella enteritidis. American Journal of Public Health. 1976 Jan;66(1):82-4.

16. CDC. Outbreaks of multidrug-resistant Salmonella Typhimurium associated with veterinary facilities—Idaho, Minnesota, and Washington, 1999. MMWR Morbidity and Mortality Weekly Report 2001;50:701–704.

17. Canadian Communicable Disease Report. Human health risk from exposure to natural dog treats. 200(26).41. Acessed June 5, 2011 at http://www.collectionscanada.gc.ca/webarchives/20071217102424/http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/00vol26/dr2606ea.html

18. Finley R, Reid-Smith R, Weese JS. Human health implications of Salmonella-contaminated natural pet treats and raw pet food. Clin Infect Dis. 2006 Mar 1;42(5):686-91. Epub 2006 Jan 20.

19. KuKanich KS. Update on Salmonella spp contamination of pet food, treats, and nutritional products and safe feeding recommendations. Journal of the American Veterinary Medical Association 2011 Jun;238(11):1430-1434.

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11 Responses to Salmonella and Other Risks of Raw Pet Diets

  1. art malernee dvm says:

    Lets fess up and not forget why we feed dog food, cooked or raw, store bought or homemade . Its because its cheap and convenient. Remove these two reasons and our pets would have a seat at the dinner table. Its hard to beat a bag of old Roy, Purina Dog Chow, or if you do not go to Walmart, Petagree who makes Ole Roy, mixed with portion controlled leftovers as a “best buy”. If you want to try to feed something better start cooking for your dog using fresh foods, locally grown, cooked when needed to destroy bacteria or make digestible using a VARIETY of food ingredients. Your physcian does not hand you a bag of food or a written formula for a homemade cooked or raw diet and tell you only to eat that bag or formula and neither should your vet.
    art malernee dvm
    fla lic 1820

  2. skeptvet says:

    I disagree. Certainly, convenience is one advantage to commercial diets, but they undoubtedly cost more than table scraps, so cost doesn’t seem a likely factor. And the reality is that they are healthier than a haphazard diet of leftovers. People suffer tremendous nutrition-related illness because we can freely indulge our anachronistic evolved preferences for salt, fat, and excess calories. The only significant nutritional disorder our pets suffer from is obesity, and that is simply because we love them with food. Commercial diets and the research to improve them has largely eliminated most of the other nutritional disorders pets suffered from when fed table food primarily.

    There’s nothing wrong with a balanced, homemade diet, of course, but 1) it is hard to make consistently in a way that is nutritionally balanced and 2) there is no evidence to support claims of health benefits superior to commercial diets. Anyone who is willing to make the effort to prepare a balanced fresh diet, I say more power to them. But I think the vast majority of pet owners are unlikely to do this and do it well, so I see absolutely nothing wrong with nutritious commercial diets for most pets.

  3. art malernee dvm says:

    I disagree. Certainly, convenience is one advantage to commercial diets, but they undoubtedly cost more than table scraps,>>>>>

    In my family table scraps is what we throw away because we did not eat it. Adding it to dry commercial dog food cost zip and helps avoid feeding a single source maintance diet which can be a risk factor for disease. I think the table scrap has gotten a bad rap.
    art

  4. Anne et Cat says:

    I think the problem of Salmonella isn’t a real problem for most of owners which use homemade diet, because often the diet is made for a day. The contamination isn’t so important to give some problems to animals.

    Sure, if you buy this product, you have all problems of conservation and contamination that you have with any fresh product.

    The problem of obesity is, in my mind, a problem of less of choice. The animal can’t select, so it eat too much. If it isn’t a pathological problem, of course.

    Thank you for this interesting article! Good evening!
    Anne

  5. skeptvet says:

    Well, storage isn’t really the source of the Salmonella problem with meat. The meat comes contaminated from the slaughter facility, and cooking eliminates the risk by killing the bacteria. Salmonella can proliferate if the meat is improperly stored, but the real problem is already there when you get the meat.

    You may be thinking of eggs, which can have very low levels of Salmonella that don’t cause a problem unless the egg is left at room temperature for too long and the bacteria replicate.

  6. art malernee dvm says:

    The conclusion that cats fed a single commercial food exclusively were at greater risk for developing taurine deficiency and dilated cardiomyopathy than cats fed a variety of foods is not unexpected. This and other examples of diet-induced disease should serve as a warning to veterinarians who prescribe or endorse the feeding of one food exclusively to any animals, especially for maintenance.’

    (Pion, P D et al, 1992)

  7. v.t. says:

    Art, could you please cite your source properly, thank you. (A simple sentence from god-knows-where doesn’t give credence to any argument)

  8. Art says:

    Here you go vt
    This should get you started
    http://www.ebvet.com/forum/viewtopic.php?t=12
    Art Malernee dvm
    Fla lic 1820

  9. tara says:

    Seems like most people know more about health and nutrition than this person hiding behind the curtain…..best advise is to stay far away from docotrs and especially mainstream so called veterinarians..they will kill your pet and take your money…

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