Find out more about Salmonella, the bacteria causing illness from consumption of raw eggs.
Salmonella
Salmonella are usually motile, non-sporeforming, and Gram-negative rod-shaped bacteria. They are widespread in the environment and are associated with all animal species including mammals, birds, reptiles, and amphibians. Salmonella have been found in water, soil, insects, on factory and kitchen surfaces, animal feces, raw meats, poultry, and seafood. While these are common sources, Salmonella have been isolated from numerous other food sources.
Symptoms of Salmonellosis
Acute symptoms may include nausea, vomiting, abdominal cramps, diarrhea, fever, and headache. Symptoms typically develop 12 to 72 hours after ingestion of contaminated food. Most infected persons recover without treatment after four to seven days. As with many food-borne pathogens, young children, the elderly, and the immunocompromised are the most common victims of serious Salmonella infections. Depending on host factors such as age and health, the infective dose has been estimated to be as low as 15 to 20 cells for some strains.
In a small percentage of cases, persons infected with Salmonella can develop chronic, long-term problems. Reactive arthritis may begin three to four weeks after onset of acute symptoms, and the arthritic symptoms can be debilitating and last for six months or more.
Those at Risk
All age groups are susceptible to infections, but salmonellosis has a more severe effect on elderly, young, and sick people. The frequency of salmonellosis in AIDS patients is estimated to be 20 times higher than the general population. School lunch programs, nursing homes, and hospitals often require food from sources with more rigorous quality assurance programs in place; these programs might include increased sanitation, stricter rules governing personal hygiene, and/or increased microbial testing of finished products.
Foods Associated with Salmonella
Salmonellosis outbreaks have occurred from a variety of foods including poultry, meats, eggs, milk products, fruit juice, fish, shrimp, frog legs, yeast, coconut, sauces and salad dressings, cake mixes, breakfast cereal, cream-filled desserts and toppings, dried gelatin, peanut butter, cocoa, chocolate, and dried spices.
The incidence of Salmonella is much higher in raw agricultural products (e.g. raw eggs, or uncooked poultry or meat) than in cooked or processed food products. However, Salmonella can occur in other foods as a result of cross-contamination with raw foods or from contamination from humans, animals, birds, or reptiles. Additionally, because of the microorganism’s ability to survive in a wide range of environments, Salmonella has been found in dry and dehydrated foods (e.g. cocoa, chocolate, dry milk, spices, and cereal products) and in higher-acid food products (e.g. non-pasteurized orange juice). Thus, preventative measures are extremely important at all food handling and processing steps.
Preventing Salmonellosis
Unfortunately, there is no vaccine to prevent salmonellosis. There are several things you can do help prevent the disease.
- Do not eat raw or undercooked eggs, poultry, or meat.
- Cook poultry and meat, including hamburgers, thoroughly and to safe temperatures (see USDA for consumer guidelines or the FDA Food Code for commercial guidelines).
- Do not consume raw or unpasteurized milk or other dairy products.
- Wash produce thoroughly.
- Keep uncooked meats separate from produce, cooked foods, and ready-to-eat foods. *Wash hands, cutting boards, counters, knives, and other utensils thoroughly after touching uncooked foods.
- Wash hands before handling food, and between handling different food items.
- Do not prepare food for others if you have been diagnosed with salmonellosis.
- Wash your hands after contact with animal feces.
- Wash hands after handling reptiles or birds. These animals carry the Salmonella bacterium and are not appropriate as pets for children.
