Study Finds 45% of Raw Pet Foods Contaminated with Dangerous Bacteria

Published: October 24, 2014
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I have recently developed a special interest in the bacterial contaminants in dog food that can be transmitted to people. Why? Because my one year old son has an obsession with our dog’s kibble. The second my back is turned he scoots his cute little butt over to Apollo’s bowl and finds that one (or more) stray kibble that escaped my notice and vacuum.

Thankfully, my dog’s food is made by a reputable manufacturer under strict quality control measures (it’s a hypoallergenic diet only available under veterinarian’s orders). That doesn’t completely eliminate the chances that my son could become sick after handling a kibble or two, but I’m confident the risk is quite small.

A recently published study shows the same could not be said if I was feeding my dog a commercially prepared raw food. Researchers analyzed dry and semimoist dog and cat food (no canned products were tested), raw dog and cat foods (e.g., those packaged in tubes), exotic animal feeds, chicken jerky products, pig ears, and bully stick-type products looking for SalmonellaListeriaEscherichia coli O157:H7 enterohemorrhagic E. coli, and Shiga toxin–producing strains of E. coli (STEC). The scientists picked these potential contaminants because of their ability to cause illness and even death in people who handle pet foods.

Scientists evaluated 480 samples of dry and semimoist food and found only two incidences of contamination, both in dry cat foods. One was positive for Salmonella and the other for Listeria greyii. This comes to a 0.4% contamination rate. None of the exotic animal feeds were contaminated.

On the other hand, of the 196 samples of raw dog and cat food, a total of 88 were found to be contaminated — 65 for Listeria, 15 for Salmonella, and 8 for STEC – a 45% contamination rate. The authors also found that two of 190 chicken jerky products, pig ears, and bully stick-type products were positive for STEC, and one was positive for Listeria — a 1.6% contamination rate.

In the past, significant disease outbreaks in people have been linked to contact with dry dog and cat foods (most notably the Diamond Pet Foods Salmonella incident in 2012). It now appears that the greatest risk associated with commercially available foods lies elsewhere. I strongly discourage the practice of feeding raw dog and cat foods, especially if someone in the household has a weak immune system (including young children and the elderly). If you choose to feed raw anyway, follow the U.S. Food and Drug Administration’s guidelines to prevent infections associated with the handling these products:

  • Thoroughly wash your hands with soap and water (for at least 20 seconds) after handling raw pet food, and after touching surfaces or objects that have come in contact with the raw food. Potential contaminated surfaces include countertops and the inside of refrigerators and microwaves. Potential contaminated objects include kitchen utensils, feeding bowls, and cutting boards.
  • Thoroughly clean and disinfect all surfaces and objects that come in contact with raw pet food. First wash with hot soapy water and then follow with a disinfectant. A solution of 1 tablespoon bleach to 1 quart (4 cups) water is an effective disinfectant. For a larger supply of the disinfectant solution, add ¼ cup bleach to 1 gallon (16 cups) water. You can also run items through the dishwasher after each use to clean and disinfect them.
  • Freeze raw meat and poultry products until you are ready to use them, and thaw them in your refrigerator or microwave, not on your countertop or in your sink.
  • Carefully handle raw and frozen meat and poultry products. Don’t rinse raw meat, poultry, fish, and seafood. Bacteria in the raw juices can splash and spread to other food and surfaces.
  • Keep raw food separate from other food.
  • Immediately cover and refrigerate what your pet doesn’t eat, or throw the leftovers out safely.
  • If you’re using raw ingredients to make your own cooked pet food, be sure to cook all food to a proper internal temperature as measured by a food thermometer. Thorough cooking kills Salmonella, Listeria monocytogenes, and other harmful foodborne bacteria.
  • Don’t kiss your pet around its mouth, and don’t let your pet lick your face. This is especially important after your pet has just finished eating raw food.
  • Thoroughly wash your hands after touching or being licked by your pet. If your pet gives you a “kiss,” be sure to also wash your face.

Dr. Jennifer Coates


Investigation of Listeria, Salmonella, and Toxigenic Escherichia coli in Various Pet Foods. Nemser SM, Doran T, Grabenstein M, McConnell T, McGrath T, Pamboukian R, Smith AC, Achen M, Danzeisen G, Kim S, Liu Y, Robeson S, Rosario G, McWilliams Wilson K, Reimschuessel R. Foodborne Pathog Dis. 2014 Sep;11(9):706-9. 

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