What is Salmonella?
Salmonella is a member of the family Enterobacteriaceae and is closely related to species of E. coli. and Shigella. There are over 2500 known serovars, with the most familiar being Salmonella enteritidis and Salmonella typhimurium.
From our perspective Salmonella enteritidis and related serovars are of particular importance because they are the bacteria most commonly associated with cases of food-borne gastroenteritis1.
How is Salmonella transmitted?
Infection occurs by eating food that is contaminated, either from the source animal during slaughter or through cross-contamination during handling and preparation of the food8.
Improper hygiene can also be a source of contamination. Proper hand washing and sanitation of the area used during cooking can prevent bacteria from being introduced by the individual preparing the meal7.
Studies with humans show an infectious dose of 105 organisms, however infection can occur at lower doses in individuals who are immunocompromised such as infants, small children or the elderly1.
Pets as a source of contamination?
Is it possible to get Salmonella from our pets? Yes, but it is important to look at how this transmission occurs. Approximately 36% of healthy dogs and 17% of healthy cats carry Salmonella in their digestive tract and therefore may shed the bacteria in their stool4. They do after all walk around sniffing each other rear ends, routing through garbage and commonly come into contact with the feces of other animals.
The transmission to humans occurs through the fecal-oral route in which bacteria get on your hands after contact with your pet’s stool. If proper hand washing practices do not exist it can then be transmitted to your food or ingested directly through contact with your mouth.
Raw food and Salmonella: is there a connection?
Raw food is a great source of nutrition for your pet. However because it is a raw meat product safe handling is required, just as you would do when preparing meat products for yourself. The food should be stored in the freezer and thawed in the refrigerator to limit bacterial growth.
Most bacteria, including Salmonella, cannot grow at temperatures less than 5°C7. When feeding a raw diet do not leave the food down available to your pet for an indefinite period of time. The food is then susceptible to bacterial growth because it is being exposed to a temperature range that is favorable to this growth. It all comes down to common sense, if the food has been sitting out for a long period of time (2 hours or more) throw it out and feed fresh food at the next mealtime. It is also important to remember to properly wash (using hot soapy water) all utensils, bowls or holding containers used and all surfaces that the food may have come into contact with. If left unwashed they can become potential sources of contamination for anyone in the home or new food when it is introduced at the next meal.
How can Salmonellosis be prevented in raw-fed animals?
The point that cannot be emphasized enough in this matter is proper hygiene when dealing with Salmonella from any source3,5. The following are some guidelines that, if followed, would greatly minimize the risk of infection:
- Store raw food in the freezer and thaw in the refrigerator.
- Properly wash hands, all bowls, utensils and contact surfaces after handling raw food.
- Limit time food is held at room temperature during feeding to less than 2 hours.
- Dispose of food left out for periods longer than 2 hours.
- Do not feed using a free-choice method where food is out and available at all times.
- After contact with animal feces wash your hands warm water and soap.
- Baron, E.J. et al. (1994) Medical Microbiology. A Short Course. John Wiley & Sons, Inc. Pg. 329-342.
- Canine Nutrition – Volhard Holistic Care. April 8, 2003. http://www.volhard .com/holistic/artbywv.htm#nut
- CDC – Healthy Pets Healthy People. February 26, 2003. http://www.cdc. gov/healthypets/diseases/salmonellosis.htm
- Hand, M.S., Thatcher, C.D., Remillard, R.L., and Roudebush, P. (2000) Small Ani- mal Clinical Nutrition. Mark Morris Institute. Pg. 36-42,188.
- Herboid, J.R. (2000) What You and Your Clients Need to Know About Zoonotic Diseases: Rabies, Lyme Disease and Salmonellosis. North American Veterinary Conference 14:833-834.
- Joffe, D.J. and Schlesinger, D.P. (2002) Preliminary assessment of the risk of Sal- monella infection in dogs fed raw chicken diets. Can Vet J 43:441-442.
- Stiles, M.E. and McMullen, L.M. (1999) Nutrition and Food Science 361/363 – Food Microbiology. University of Alberta. Pg.196-209.
- Wills, J.M. and Simpson K.W. (1994) The Waltham Book of Clinical Nutrition of the Dog and Cat. Pergamon Publishers. Pg. 157-158.