From 2006-2008, there was a prolonged multistate outbreak of Salmonella enterica serotype Schwarzengrund infections in humans. A total of 79 cases from 21 states were reported. The source of infection was identified as dry dog food produced at a manufacturing plant in Pennsylvania. This investigation was the first to identify contaminated dry dog food as a source of human Salmonella infections.
In spring 2012, an outbreak of Salmonella Infantis was traced to a Diamond Foods production facility in Gaston, SC. A total of 49 individuals (47 individuals in 20 states and two individuals in Canada) were infected with the outbreak strain. Seventeen brands representing >30,000 tons of dry dog and cat food produced at the facility were recalled as a result of the outbreak.
“Natural” pet treats, such as pig ears and dehydrated/dried beef and fish, have also been implicated in illness in the U.S. due to infection with Salmonella bacteria.
Below are answers to the questions we've received about this issue.
Q: Why does it seem there are more foods being recalled due to Salmonella? Does this mean that pet foods aren't safe?
A: There are several potential reasons for this. One potential reason is that the large-scale, melamine- related pet food recall of 2007 increased public and media awareness of and sensitivity to pet food safety concerns. Another potential reason is the increased vigilance of the manufacturers and the federal government regarding Salmonella and other public health concerns, leading to increased surveillance and reporting. A third, and very important, potential reason is the launch of an early detection reporting system – the Reportable Food Registry – that requires and allows immediate reporting of safety problems with food and animal feed (including pet food), instead of relying on inspection to identify problems. According to a July 2010 FDA press release, the registry has been very successful in identifying at-risk foods.
The detection of Salmonella or other bacteria in a commercially processed pet food triggers a cascade of events at the state and federal level that lead to a voluntary recall by the pet food manufacturer. The pet food is considered adulterated and not fit for distribution.
And no, this is not an indication that pet foods are unsafe. Considering that the majority of these recalls have been precautionary and not associated with illness in pets or people, these recalls may indicate that they are preventing illness by catching the problems earlier.
That said, the fact remains that there have been illnesses linked to commercially processed pet food, and precautions should be taken (see below).
Q: Are certain types of pet foods more likely to be contaminated with Salmonella?
A: No pet food is immune from the possibility of Salmonella contamination. There is evidence, however, that feeding raw foods, such as raw meat and eggs, increases the risk of Salmonella infection and shedding of the bacteria (leading to possible infection of other animals and of people).2-9 Regardless of the type of food you choose to feed your pet, proper precautions should be taken to protect your family's health.
Q: How can pet food become contaminated with Salmonella?
A: Because pet foods and treats contain animal-origin products, they are at risk of contamination with Salmonella, E. coli, and other organisms. In general, these products are cooked to temperatures that will kill these organisms – however, if a contaminated additive (a flavoring, for example) is added to the food after cooking or if the food comes in contact with contaminated materials, the food will be contaminated. There are many safeguards in place to minimize the risk of contamination during the manufacturing process, but using caution when handling these foods is always recommended.
Q: How can pet food infect me or my pet with Salmonella?
A: Salmonella infection, like many other food-borne infections, usually occurs after the bacteria are ingested – this can occur by eating or drinking contaminated products, or by coming into contact with contaminated products and then touching your mouth, face or food. The organism enters your gastrointestinal tract and causes disease.
Q: Are certain people at higher risk of infection with Salmonella from contaminated food?
A: Yes. People whose immune systems are compromised (by chronic disease, drug therapy, cancer, etc.) are at high risk of infection if exposed to Salmonella, as are old and very young people. In the recent study in Pediatrics,1 almost one-half of the infections occurred in children aged 2 years or younger.
Q: How would I know if my pet had a Salmonella infection?
A: Pets with Salmonella infections may be lethargic and have diarrhea or bloody diarrhea, fever, and vomiting. Some pets will have a decreased appetite, fever and abdominal pain. However, not all pets carrying Salmonella will appear sick. Apparently well but infected animals can be carriers and may infect other animals or humans, particularly through exposure to their feces. If your pet has consumed the recalled product and has these signs, please contact your veterinarian.
Q: How would I know if I had a Salmonella infection?
A: People infected with Salmonella often develop diarrhea, fever and abdominal cramps 12-72 hours after infection. If you have any of these symptoms, contact your physician.
Q: What can I do to prevent getting Salmonella from pet food products or treats?
A: Luckily, common sense measures are effective in minimizing your risk of infection. These measures are particularly important if you feed your pet raw foods of animal origin (eg, raw beef, chicken or eggs), including raw treats such as raw hides and pig ear chews.
- Only purchase products (canned or bagged) with no visible signs of damage to the packaging, such as dents, tears or discolorations.
- Safely handle all pet foods and treats
- Wash your hands thoroughly after handling any pet food or treats and especially before preparing, serving or eating food, drinks or preparing baby bottles.
- Don't allow your children to handle the food; or, if you choose to let them handle the pet food or treats, make sure they thoroughly wash their hands (under your direct supervision) afterwards.
- Do not allow immunocompromised, very young, or elderly people to handle pet food and treats; or, if they handle the products, they should thoroughly wash their hands immediately after handling the products.
- Keep all pet foods and treats away from your family's food.
- Do not prepare pet foods in the same area or with the same equipment/utensils you use to prepare human foods.
- Do not allow pets on countertops or other areas where human food is prepared.
- Promptly refrigerate or discard unused, leftover wet pet food and containers (e.g., cans, pouches). Refrigerating foods quickly prevents the growth of most harmful bacteria.
- In the Pediatrics manuscript,1 feeding pets in the kitchen was identified as an important source of infection. If it is possible for you to feed your pet in an area other than your kitchen, you may wish to consider doing so. If it is not an option, or if you choose to feed your pet in the kitchen, feed your pet as far away from human food preparation areas as possible and follow the other guidelines above.
The CDC also has a podcast with tips to reduce your risk of getting Salmonella infection from dry pet food.
- Behravesh CB, Ferraro A, Deasy M, et al. Human Salmonella infections linked to contaminated dry dog and cat food, 2006-2008. Pediatrics 2010; 126: 477-483. Abstract available at http://pediatrics.aappublications.org/cgi/content/abstract/peds.2009-3273v1.
- Leonard EK, Pearl DL, Finley RL, et al. 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 2010 Feb 16. Abstract available via PubMed at http://www.ncbi.nlm.nih.gov/pubmed/20163574.
- Lefebvre SL, Reid-Smith R, Boerlin P et al. Evaluation of the risks of shedding Salmonellae and other potential pathogens by therapy dogs fed raw diets in Ontario and Alberta. Zoonoses Public Health 2008; 55: 470-480. Abstract available via PubMed at http://www.ncbi.nlm.nih.gov/pubmed/18811908.
- Finley R, Reid-Smith R, Ribble C, et al. The occurrence and antimicrobial susceptibility of salmonellae isolated from commercially available canine raw food diets in three Canadian cities. Zoonoses Public Health 2008; 55: 462-469. Abstract available via PubMed at http://www.ncbi.nlm.nih.gov/pubmed/18811907.
- Strohmeyer RA, Morley PS, Hyatt DR, et al. Evaluation of bacterial and protozoal contamination of commercially available raw meat diets for dogs. J Amer Vet Med Assoc 2006; 228: 537-542. Abstract available via PubMed at http://www.ncbi.nlm.nih.gov/pubmed/16478425.
- Finley R, Reid-Smith R, Weese JS. Human health implications of Salmonella-contaminated natural pet treats and raw pet food. Clin Infect Dis 2006; 42: 686-691. Abstract available via PubMed at http://www.ncbi.nlm.nih.gov/pubmed/16447116.
- Weese JS, Rousseau J, Arroyo L. Bacteriological evaluation of commercial canine and feline raw diets. Can Vet J 2005; 46: 513-516. Abstract available via PubMed at http://www.ncbi.nlm.nih.gov/pubmed/16048011.
- Stiver SL, Frazier KS, Mauel MJ, et al. Septicemic salmonellosis in two cats fed a raw-meat diet. J Am Anim Hosp Assoc 2003; 39: 538-542.
- Joffe DJ, Schlessinger DP. Preliminary assessment of the risk of Salmonella infection in dogs fed raw chicken diets. Can Vet J 2002; 43: 441-442.