A salmonella infection is caused by salmonella bacteria. These bacteria live in the intestines of humans and animals. Problems arise when food and water are contaminated with salmonella bacteria, which come from the feces of humans or animals. Foods most commonly associated with salmonella infections are raw meat, eggs, fruit and vegetables. According to the Centers for Disease Control and Prevention (CDC), contaminated foods often look and smell normal. Thorough cooking kills the bacteria, but food can become contaminated by the unwashed hands of a food handler.
Meat
According to the Mayo Clinic, raw meat and poultry can become contaminated during butchering when feces and intestinal contents of the animals come in contact with the meat. Seafood harvested from contaminated water can also contain salmonella bacteria. According to the CDC, to prevent a salmonella infection, meat should be well cooked, not pink in the middle. Foods such as hamburger patties that mingle the meat from many animals are of particular concern because bacteria in the meat from one animal can contaminate the entire batch.
Eggs
Although it probably seemed cruel, your mom was right not to let you eat raw cookie dough. She was trying to protect you from a salmonella infection from raw eggs used in the dough. According to the CDC, eggs can be contaminated with salmonella because some types of these bacteria can infect a hen's ovary. The egg can become infected this way even before the shell is formed. Raw eggs are also used in homemade versions of Hollandaise sauce, salad dressings, mayonnaise, tiramisu and frostings. To prevent a salmonella infection, the CDC recommends people not eat raw or undercooked eggs.
Fruits and Vegetables
Fresh fruits and vegetables that are washed or irrigated with water contaminated with sewage or manure can cause a salmonella infection when eaten. The quality of water used for chilling the produce is also crucial. According to the CDC, washing the fruits and vegetables decreases but doesn't eliminate the chances for contamination. Cross-contamination can occur in the kitchen when fruits and vegetables come in contact with juices from raw meat. Alfalfa sprouts and other sprouts are grown under conditions that favor the growth of bacteria, so they are of particular concern. Just a few bacteria on the seeds can multiply once the sprouts are ready to eat. Fruit juice is also subject to contamination if not pasteurized. Removing the outer leaves of lettuce heads and cabbages is one way to reduce the risk for salmonella infection.
