Most of us have heard of salmonella before, particularly in conjunction with eggs. It is well-known that eggs are often carriers of this bacteria; many restaurants such as International House of Pancakes (IHOP) now include warnings about salmonella on their menus. In order to prevent infection, eggs must be thoroughly cooked – sunny side up or over easy is an invitation to a stomach ache or worse! (I prefer over-easy eggs, but I’ve started ordering them scrambled instead)

Let’s back up. There are some important facts that everyone needs to know about this digestive bombshell. For example, salmonella is a group of related bacteria, not a virus. This is good news, since most bacteria can be treated with antibiotics. It primarily affects the digestive tract. Salmonella Typhimurium and Salmonella Enteritidis are the most common types that cause digestive illness in the United States. Another type of salmonella causes typhoid fever in developing countries. The initial discovery of salmonella bacteria occurred over 100 years ago.

A person infected with salmonella has salmonellosis. The incubation period is usually 24-72 hours. At that time, the individual will develop nausea and vomiting, watery diarrhea, and abdominal pain / cramps. About half of all infected persons will also have fever. The illness may last up to a week. It is estimated that salmonella is responsible for at least 15% of food poisoning episodes in the U.S.; however, this figure may be low, since the infection is often not reported. Cultures are required to confirm the diagnosis and many people don’t go to the doctor unless their symptoms are severe. Many cases of ‘stomach flu’ are actually salmonellosis.

If the individual is an otherwise healthy adult, the infection is usually stopped by the immune system. Children, adolescents, the elderly, and chronically ill patients are more likely to have complications (although they are still considered rare). If the immune system does not fight off the infection effectively, the bacteria can move from the digestive tract into the bloodstream (so-called “blood poisoning” or bacteremia). The circulatory system gives salmonella a free ride to virtually every system in the body, so any area that is already compromised (through genetic predisposition or chronic illness) is liable to be infected. Thus, complications from salmonellosis include bone and joint infections, pneumonia, hepatitis, meningitis, and pericarditis (infection of the sac around the heart). In some cases, the resulting infection can be lifelong and recurrent, such as in the case of three Midwest teenagers who contracted severe salmonellosis and subsequent arthritis after eating contaminated ice cream.

As indicated by the ice cream example, salmonella bacteria can be found in more places than just eggs. Chicken (and other poultry) is another common source – in fact, the reason eggs can be dangerous in spite of external disinfection is that the bacterium is passed directly from the infected hen to the yolk and white of the egg. Poultry must be handled carefully in order to prevent incidental contamination (more about this below). Other sources include beef, unwashed fruits and vegetables, pork, and any other food item that might be contaminated by contact with infected food products or their residue, as well as food prepared by individuals infected with salmonella who do not practice good hygiene (such as hand-washing). In the ice cream incident in the Midwest, a truck that hauled unpasteurized liquid eggs was later used to haul ice cream mix, without thorough cleaning of the tank, hoses, and valves in between. This source of contamination was very difficult to trace; in fact, its discovery was based on an anonymous tip from a truck driver.

Salmonella can also be transmitted by pets, particularly turtles, iguanas, and chicks. Dogs and cats have also been implicated in some outbreaks of the disease.

What can you do to prevent salmonellosis in yourself and your family? First, if there are young children in the home, avoid turtles, iguanas, and chicks as pets. If you have them, make absolutely sure the child washes his/her hands after handling the animal.

Recipes that include raw eggs are risky – this includes meringues, mousse, and protein drinks with raw eggs or egg whites. Eggs should be fully cooked until both yolk and white are solid. When preparing chicken or other poultry (or any kind of meat), keep it away from other foods, especially those that will be served raw such as salad vegetables. Any surface touched by the meat and/or by meat juices should be disinfected before any other food or utensil touches it. Also, wash your hands thoroughly before handling other food and before touching your mouth, nose, or face. With some precautions, you should be able to avoid salmonella, but if it does strike, make sure you stay hydrated. Very young children, elderly individuals, or those with chronic illness should see a doctor as soon as possible.