The following was originally published in March of 2002. Recently, more talk about this topic has been stimulated on social media after an EPA document was uncovered that showed that "euthanized" pets from animal shelters were being used in pet foods. We are, therefore, republishing it to help pet owners better understand the issues and to help animal shelters make better choices about which pet foods they use, sell and promote.
Advocates working to end the killing of healthy and treatable dogs and cats should also understand that, because dogs and cats destroyed in animal shelters are very inexpensive meat sources, a large network of businesses benefit financially from the killing that takes place in animal shelters. This includes pet food manufacturers, pet stores, veterinarians and even animal shelters themselves.
We have updated the original article slightly, and provide recommendations at the end for avoiding foods that may contain sodium pentobarbital ("euthanasia" solution).
In June of 2001, I first reported on a study conducted jointly by the Center for Veterinary Medicine (CVM) and the Food and Drug Administration (FDA). The study took samples of pet foods and tested them for the presence of sodium pentobarbital, the agent often used to end the lives of dogs, cats and other animals in animal shelters and veterinary hospitals. Since 1998, consumers have been waiting to know the results of the study. In March of 2002, the study was finally released. We are providing this overview of the study results in order to help make pet owners more aware of the significant issues surrounding many commercial pet foods. History of the study Following growing reports that dogs and cats were becoming increasingly resistant to sodium pentobarbital the FDA and CVM sought to determine whether or not euthanasia agents used to kill companion animals could survive the rendering process. While an earlier study at the University of Minnesota concluded that sodium pentobarbital would survive rendering, this study was undertaken in an effort to shed more light on the subject by actually detecting the presence of the drug in commercial pet foods purchased in retail stores. About the Study Two sets of surveys were conducted, the first in 1998 and the second in 2000. In the initial survey, samples were simply tested to determine whether or not they contained sodium pentobarbital. During the 2000 survey, additional testing was performed to determine the amount of the drug present in each sample. In total, 150 samples were tested. Data was recorded regarding manufacturer, brand and formula of the pet food. Additionally, lot numbers for each sample were recorded. This study sought to answer several questions concerning the presence of euthanasia agent in pet food. The first, and to many, the most significant finding of the study was the surprisingly high percentage of pet foods that tested positive for sodium pentobarbital. Of the 150 samples, there were 49 which had no result, or for which the results could not be determined. These samples could neither be classified as positive or negative. Of the remaining 101, 54 samples (53 percent of the formulas from which results could be determined) contained sodium pentobarbital. As a follow up to this study, the FDA performed sodium pentobarbital tests on Beagle subjects in an effort to determine what effect this drug might be causing in companion animals. To make this determination, the FDA isolated one liver enzyme to use as a benchmark in their analysis. Different daily oral doses of sodium pentobarbital were administered to different test subjects. Blood was then drawn and the level of this liver enzyme was evaluated to determine if it had increased. How Euthanasia Solution Gets into Pet Food In recent years, it has become widely known that companion animal carcasses from animal shelters and veterinary hospitals make their way to rendering plants where they are processed for pet foods. Some estimate that billions (Yes. That is billions, with a "b") of pounds of companion animal carcasses are disposed of in this manner each year in the USA. The majority of these animals have been killed with sodium pentobarbital. Surprisingly, there is no law that prohibits the use of companion animals in pet food. There is also no law that prohibits toxic agents, like sodium pentobarbital, from entering pet foods. As part of this study, researchers developed tests for dog and cat DNA which might be present in the foods. According to the researchers, their test are capable of detecting as little as 5 pounds of dog and cat in a sample of 50 tons of finished feed. In their tests, they found no evidence of dog or cat DNA. This result has surprised many people, since the use of dogs and cats in pet food has been widely documented in recent years. There is speculation that other possible sources of sodium pentobarbital may include horses or other livestock that have been killed by lethal injection. Problems with the Report While we applaud the FDA and the CVM for looking into this issue, it seems unimaginable that sodium pentobarbital was first discovered in pet food in 1998, and that nothing has yet been done to eliminate this substance from the food supply of our companion animals. Had sodium pentobarbital been found in human foods, according the FDA, there would have been an immediate recall and production stopped. Rather than taking this common-sense approach, the FDA chose to avoid any real action, by, instead, conducting the liver enzyme test. While the desire to measure the possible long-term effects of sodium pentobarbital exposure is understandable, the study conducted was inadequate to meet that goal because: 1) To determine whether a dose of drug was having a measurable effect on dogs in the study, the FDA measured a single liver enzyme. They then sought to find the minimal daily dose that did not elevate this enzyme. While it may be true (no one knows) that this enzyme is a good indicator of the overall effect this drug has on the body, it certainly is not the only potential indicator. Clearly other effects could be occurring that would not be measured by this one enzyme. 2) It is unclear what life stages the test animals included. If they included young puppies, pregnant dogs or geriatric pets, would the tests have been different? 3) The FDA tests did not check for possible interactions with other drugs. 4) They did not test for possible interactions with other common chemicals found in pet foods. 5) The FDA acknowledges that they do not really know what possible impact the pentobarbital may have at the levels found in the study, yet they have concluded they are "probably" safe. 6) The FDA acknowledges that had these levels of drug been found in human food, an instant recall would have been mandated and production of the food stopped. 7) The overall number of samples was quite small and the results inconsistent. Given the varying amount of drug detected, it is reasonable to assume there are products that contain higher levels than were found by this limited survey.
8) DNA experts have stated that dog and cat DNA would be unlikely to survive the rendering and pet food manufacturing process, which is almost certainly the only reason dog and cat DNA was not found. It is also worth pointing out that given that this study was initiated due to an observable reaction to the drug (i.e. increased tolerance to it). It therefore does not seem at all rational to conclude the drug is not having an impact on the animals consuming foods contaminated with sodium pentobarbital. Conclusions According to the study, there is a direct correlation to products containing certain ingredients and the presence of drug. The study indicated that pet food product that contain ingredients derived from unidentified animal sources, like "meat and bone meal," "animal tallow" or "animal fat" appear to be much more likely to be contaminated with this drug.
We believe that consumers should seek out pet foods that do not contain these ingredients, or that are labeled "USDA Certified Organic" because the inclusion of these ingredients would render (pun intended) pet foods ineligible for this certification.
Furthermore, we believe that animal shelters should take great care to ensure they are not contributing to the contamination of the pet food supply. They can do this by eliminating all unnecessary killing and by refusing to send the animals that have been euthanized to rendering plants.