Food poisoning is caused by eating food contaminated with bacteria, viruses, parasites or toxins. There are more than 250 different kinds of food poisoning, and the symptoms vary depending on the cause of the disease, according to the Centers for Disease Control and Prevention (CDC). The most common symptoms are nausea, vomiting, cramps and diarrhea. Food can become contaminated at any point during its production or due to improper cooking.
Causes
The most common causes of food poisoning are the bacteria Campylobacter, Salmonella and E. coli O157:H7, as well as a group of viruses commonly known as the Norwalk virus, reports the CDC. Campylobacter causes fever, diarrhea and cramps, and it is the most commonly known cause of bacterial diarrhea in the world. Salmonella also causes fever, diarrhea and cramps, but in people who are already sick it can also cause a life-threatening infection. E.coli causes bloody diarrhea and severe cramps, but can also progress in a few people to cause anemia, bleeding and kidney failure. Norwalk viruses are extremely common but rarely diagnosed because the tests are often not available. Norwalk viruses cause more vomiting than diarrhea, and usually resolve in a couple of days. Many cases of food poisoning are caused by other, less common pathogens.
Risky Foods
Raw animal foods are the most likely to be contaminated and cause food poisoning, according to the CDC. This makes raw or undercooked meat, poultry, eggs, unpasteurized milk and cheese, and raw shellfish the riskiest foods if you are looking to avoid food poisoning. Raw fruits and vegetables are also a concern if they have been processed in unsanitary conditions. Washing produce reduces the risk but does not eliminate it. Sprouts, like alfalfa or bean sprouts, are particularly risky because the wet conditions they are grown in can be breeding grounds for bacteria, and sprouts are usually eaten uncooked. Unpasteurized fruit juice can also be a risk.
Food Handling Risks
Kitchen workers or home cooks who do not wash their hands can contaminate food if they themselves are infected by a food-borne pathogen. You can contaminate food if it touches other contaminated food, or contaminated kitchen utensils or equipment. So, for example, if you cut up a contaminated chicken on a cutting board but do not wash the board before slicing vegetables on it, you may contaminate the salad you make from those vegetables. Proper cooking kills food-borne pathogens, but if the internal temperature of the food does not reach at least 160 degrees Fahrenheit, the germs can survive to sicken whoever eats the food. Failing to promptly refrigerate food after cooking, or improperly defrosting it, can cause just a handful of bacteria --- too few to sicken anyone --- to grow into a dangerously large colony.
Who's Most at Risk
Some people are more likely to contract food poisoning and may be at higher risk if they do get sick, according to MayoClinic.com. Pregnant women, older people, infants and young children, people with impaired immune systems and those with chronic conditions like diabetes are more likely to contract severe food poisoning. Bottle-fed infants can be at risk for food poisoning if warm formula is left in the bottle at room temperature for several hours. People with liver disease are particularly vulnerable to food poisoning from raw oysters and should avoid them.
