Raw Diets For Pets – The Freezing Myth

Recently, I’ve had several people ask me about raw pet diets commonly called BARF.  When I first heard about this diet, the letters stood for “bones and raw food”.  Now the marketing has changed to “biologically appropriate raw food”.  In these discussions, I have learned that many people believe freezing makes raw diets safe for their pets.  This is not true.  Given the buzz around raw meat diets, I feel compelled to alert everyone about the scientific findings on the topic.

According to Betsy Berry, Manager of the United States Department of Agriculture’s Meat and Poultry Hot line, “Freezing merely puts the bacteria in suspended animation.”   It does not eliminate bacteria.  Think of the recalls for frozen hamburger patties destined for human consumption.  In fact, freezing is the method of choice for storing bacteria in research settings!  Scientists have been able to culture bacteria after a millennium in the permafrost.   

Heat is one of the most commonly used methods to destroy bacteria in food and on inanimate objects. Remember passing a loop through the flame of a Bunsen burner to sterilize it in biology?  Autoclaves use a combination of heat and pressure to destroy pathogens on surgical instruments.  Milk is pasteurized and meat is cooked to an internal temperature of around 160 degrees Fahrenheit to destroy bacteria.  (The USDA/Food Safety and Inspection Service provides fact sheets on their web site for safe food handling.  Please refer to them for specific details on  handling different types of meat.)    

To make a raw diet safe, everything added must be free of pathogens.  Ideally, that means each piece of meat should be cultured prior to feeding to detect pathogens such as Salmonella, E. coli and Campylobactor.  I do not know of any commercially available BARF diet that guarantees pathogen-free contents.  In commercial raw diets tested in three Canadian cities, the Salmonella prevalence was 21%.  Also, do not confuse the term organic with pathogen-free.  Organic generally means without chemicals while pathogen-free means the product is free of pathogens.  In my experience, BARF made with human grade products has less contamination than the other grades of meat.  But the risk is always there.  That’s why posters at the butcher counter and menus warn about the inherent risks of consuming raw or undercooked meat products.  

Whether you feed raw diets or not, now you know the science. 

Finley, R. et al., The Occurrence Of Microbiological Susceptibility Of Salmonellae Isolated From Commercially Available Raw Food Diets In Three Canadian Cities, Zoonoses Public Health, Oct. 2008;55 (8-10):426-9.

Inman M., Frozen Bacteria Repair Own DNA For Millennia, National Geographic News, 8/27/08.

Weese, J.S, Infectious Disease Risks Of Feeding Raw Diets, ACVIM 2006

Published by kristennelsondvm

Dr. Kristen Nelson grew up on a farm in Watertown, Minn., where she developed a deep love for animals of all kinds. She received a Doctor of Veterinary Medicine degree from the University of Minnesota, College of Veterinary Medicine. Kris then completed a small-animal internship at the prestigious Animal Medical Center in New York City. In addition to writing and speaking, she cares for small and exotic animals in Scottsdale, Az. Dr. Nelson is widely quoted in the media. Her credits include Ladies’ Home Journal, USA TODAY, the Los Angeles Times and numerous radio and television interviews. Dr. Nelson has written two books, Coated With Fur: A Vet’s Life and Coated With Fur: A Blind Cat’s Love. Kris and her husband Steve share their home with rescued cats, birds and a dog.