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Salmonella, one family of bacteria known for causing foodborne illness, live happily and naturally in the stomachs of many different animals, pets and livestock alike. There are two common ways humans contract Salmonella from animals: by consuming food contaminated with feces or by touching the feces of household pets and transferring the bacteria from our hands to our mouth.  

Unless you feel like living in a bubble, you’re probably not going to avoid all situations where Salmonella is present. Many people have pets, and everyone eats, but knowing the situations and places the bacteria appear is half the battle. 

Animals: Pets may be carriers of Salmonella bacteria, and it is likely as an owner you’ll come into contact with their contaminated feces.  Reptiles, rodents and birds are the most common carriers of Salmonella.   

Cows and chickens are also carriers of Salmonella.  Therefore, poultry, eggs, beef, milk and cheese can also be contaminated with the bacteria.  Animal products are contaminated when bacteria on the animal’s skin or hide are passed to the meat’s surface through cross-contamination during processing, usually on butchers’ knives. Feces can also come in contact with a cow’s udder and infect milk or infect eggs as they pass from a hen. 

Produce: Fertilizer, soil and water are the primary culprit when Salmonella finds its way onto produce.  If fertilizer contains contaminated manure, or runoff from neighboring land brings livestock feces with it, produce becomes contaminated. 

Even leafy greens can become contaminated by birds defecating on the crop as they fly overhead. If produce isn’t thoroughly cleaned before packaging, consumers have a high risk of consuming the bacteria.

In addition, a food service worker or handler infected with Salmonella can contaminate the food you eat if they fail to practice proper hygiene.

Incubation

After someone becomes infected with Salmonella, it can take anywhere from 12 hours to 3 days for symptoms to develop. 

Symptoms

A number of gastrointestinal and flu-like symptoms will appear during a Salmonella infection, including:

• Nausea
• Vomiting
• Abdominal pain
• Diarrhea
• Fever
• Chills
• Headache
• Muscle pains
• Blood in the stool

Typhoid fever, an illness caused by the species Salmonella typhi, results in symptoms varying greatly from typical salmonellosis, including:

• Diarrhea or constipation
• Fever greater than 102 degrees Fahrenheit (38.8 Celsius)
• Slightly raised, rose-colored spots on upper chest
• Cough
• Mental confusion
• Slowed heartbeat
• Enlargement of liver and spleen

Duration

After symptom onset, salmonellosis lasts approximately 4 to 7 days.   While most people recover fully from their illness after a week, some may experience abnormal bowel movements in the following months, and a small number of infected individuals will develop Reiter’s Syndrome, also referred to as reactive arthritis. Reiter’s Syndrome, a condition where the body’s immune system overreacts to an infection, causes symptoms such as joint pain and swelling, eye pain and redness, back pain, rashes, fever and chills.  

Action

Salmonellosis can only be diagnosed by a physician.  Most people who contract Salmonella will not require medical care.  You can prevent dehydration by drinking plenty of fluids (try drinking one cup for every large, watery stool you have), eating salty foods to help contain electrolytes and prevent dehydration and trying to stick to your normal diet to ensure your body is receiving enough nutrients. 

A doctor will usually only prescribe antibiotics if a Salmonella infection has spread from the intestines to other parts of the body.

Prevention

Avoiding Salmonella is as simple as ensuring food is prepared and cooked properly.  Some rules to follow include:

• Don’t eat raw or undercooked eggs. Foods such as homemade hollandaise sauce, some salad dressings, homemade ice cream, homemade mayonnaise, tiramisu, cookie dough, cake or brownie batter and frosting may contain raw egg.
• Only eat and drink pasteurized dairy products. Raw or unpasteurized milk is not heated to a high enough temperature to kill harmful bacteria.  When purchasing soft cheese products in particular, check the label to make sure the cheese was produced using pasteurized milk.
• Cook all meat and poultry to a food-safe temperature.  Be sure to use a meat thermometer rather than guess by the color of the meat – “no pink” does not necessarily mean “no bacteria.”
• Wash and peel raw produce before eating.
• Avoid cross-contamination by keeping raw meat separate from produce, cooked foods and ready-to-eat foods. Wash all utensils and cutting boards that have come into contact with raw meat before using them on other already-prepared foods.
• Wash your hands, a lot.  Specifically, wash your hands before preparing any food, and wash after handling raw meat and before handling cooked and ready-to-eat foods. 
• Wash your hands after coming into contact with animal feces.  Pet reptiles, birds and rats are all potential Salmonella carriers in your home, and you should wash your hands after handling them as well. 
• If you are sick with salmonellosis, don’t prepare food or drink for other people and wash your hands frequently.

Sources:

Foodsafety.gov. “Salmonella,” http://www.foodsafety.gov/poisoning/causes/bacteriaviruses/salmonella.html; accessed 29 Oct. 2009.

Web MD. “CDC: Pet Rodents Can Carry Salmonella,” http://www.webmd.com/news/20050505/cdc-pet-rodents-can-carry-salmonella; accessed 29 Oct. 2009.

Scientific Blogging. “How does Salmonella contaminate produce,” http://www.scientificblogging.com/news_releases/how_does_salmonella_contaminate_produce; 2 Sept. 2008.

Web MD. “Salmonellosis,” http://www.webmd.com/food-recipes/food-poisoning/tc/salmonellosis-topic-overview?page=2; accessed 29 Oct. 2009.