In the scramble to make sense of a mysterious strain of Salmonella that has sickened 167 people in 17 states, health officials are now pointing to tainted tomatoes as a likely culprit.
Many consumers, however, may be left with questions about Salmonella. The U.S. Centers for Disease Control and Prevention (CDC) provides a fact sheet on the bacteria to help explain the origins, risk factors and symptoms of infection with Salmonella, or Salmonellosis.
What Is Salmonellosis?
Salmonellosis is an infection of the bacteria Salmonella. Most persons infected with Salmonella develop diarrhea, fever and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most patients recover without treatment. However, in some cases, the diarrhea may be so severe that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites. Death is possible unless the person is treated promptly with antibiotics. The elderly, infants and those with impaired immune systems are more likely to have a severe illness.
How Can Salmonella Infections Be Diagnosed?
Many different kinds of illnesses can cause diarrhea, fever or abdominal cramps. Determining that Salmonella is the cause of the illness depends on laboratory tests that identify Salmonella in the stool of an infected person. Once Salmonella has been identified, further testing can determine its specific type.
How Can Salmonella Infections Be Treated?
Salmonella infections usually resolve in five to seven days and often do not require treatment other than oral fluids. Persons with severe diarrhea may require rehydration with intravenous fluids. Antibiotics, such as ampicillin, trimethoprim-sulfamethoxazole or ciprofloxacin, are not usually necessary unless the infection spreads from the intestines. Some Salmonella bacteria have become resistant to antibiotics, largely as a result of their use to promote the growth of food animals.
How Do People Catch Salmonella?
Salmonella live in the intestinal tracts of humans and other animals, including birds. Salmonella are usually transmitted to humans by eating foods contaminated with animal feces. Contaminated foods usually look and smell normal. Contaminated foods are often of animal origin, such as beef, poultry, milk or eggs, but any food, including vegetables, may become contaminated. Thorough cooking kills Salmonella. Food may also become contaminated by the hands of an infected food handler who did not wash with soap after using the bathroom.
Salmonella may also be found in the feces of some pets, especially those with diarrhea, and people can become infected if they do not wash their hands after contact with pets or pet feces. Reptiles, such as turtles, lizards and snakes, are particularly likely to harbor Salmonella.
Many chicks and young birds carry Salmonella in their feces. People should always wash their hands immediately after handling a reptile or bird, even if the animal is healthy. Adults should also assure that children wash their hands after handling a reptile or bird, or after touching its environment.
What Can a Person Do to Prevent This Illness?
There is no vaccine to prevent Salmonellosis. Because foods of animal origin may be contaminated with Salmonella, people should not eat raw or undercooked eggs, poultry, or meat. Raw eggs may be unrecognized in some foods, such as homemade hollandaise sauce, Caesar and other homemade salad dressings, tiramisu, homemade ice cream, homemade mayonnaise, cookie dough, and frostings. Poultry and meat, including hamburgers, should be well-cooked, not pink in the middle. Persons also should not consume raw or unpasteurized milk or other dairy products. Produce should be thoroughly washed.
Cross-contamination of foods should be avoided. Uncooked meats should be kept separate from produce, cooked foods, and ready-to-eat foods. Hands, cutting boards, counters, knives, and other utensils should be washed thoroughly after touching uncooked foods. Hand should be washed before handling food, and between handling different food items.
People who have Salmonellosis should not prepare food or pour water for others until their diarrhea has resolved. Many health departments require that restaurant workers with Salmonella infection have a stool test showing that they are no longer carrying the bacterium before they return to work.
Because reptiles are particularly likely to have Salmonella, and it can contaminate their skin, everyone should immediately wash their hands after handling reptiles. Reptiles (including turtles) are not appropriate pets for small children and should not be in the same house as an infant.
Salmonella carried in the intestines of chicks and ducklings contaminates their environment and the entire surface of the animal. Children can be exposed to the bacteria by simply holding, cuddling or kissing the birds. Children should not handle baby chicks or other young birds. Everyone should immediately wash their hands after touching birds, including baby chicks and ducklings, or their environment.
More Tips to Prevent Salmonellosis
Cook poultry, ground beef and eggs thoroughly. Do not eat or drink foods containing raw eggs or raw (unpasteurized) milk.
If you are served undercooked meat, poultry or eggs in a restaurant, don't hesitate to send it back to the kitchen for further cooking.
Wash hands, kitchen work surfaces and utensils with soap and water immediately after they have been in contact with raw meat or poultry.
Be particularly careful with foods prepared for infants, the elderly and the immunocompromised.
Wash hands with soap after handling reptiles, birds or baby chicks, and after contact with pet feces.
Avoid direct or even indirect contact between reptiles (turtles, iguanas, other lizards, snakes) and infants or immunocompromised persons.
Don't work with raw poultry or meat, and an infant (e.g., feed, change diaper) at the same time.
Mother's milk is the safest food for young infants. Breastfeeding prevents Salmonellosis and many other health problems.
For more information, visit the CDC's disease listing for Salmonellosis here.