DISEASE

Food Borne Diseases

OVERVIEW | CAUSES | RISK FACTORS | SYMPTOMS | COMPLICATION | DIAGNOSIS | TREATMENT | PREVENTION | REFERENCES

Food Borne Diseases

OVERVIEW

Food Borne Diseases, more commonly known as Food poisoning, is illness caused by eating contaminated food. Infectious organisms- including bacteria, viruses and parasites- or their toxins are the most common causes of food poisoning.

Infectious organisms or their toxins can contaminate food at any point of processing or production. Contamination can also occur at home if food is incorrectly handled or cooked.

Food poisoning symptoms, which can start within hours of eating contaminated food, often include nausea, vomiting or diarrhea. Most often, food poisoning is mild and resolves without treatment. But some people need to go to the hospital.

CAUSES

There are more than 250 types of food poisoning. Some of the most common germs and parasites that cause food poisoning are:

E. coli: Usually found in undercooked meat and raw vegetables, E. coli can cause serious health problems, especially in young children.
Listeria: Bacteria in soft cheeses, deli meats, and raw sprouts can cause an infection called listeriosis, which is especially dangerous for pregnant women.
Norovirus: People can get norovirus by eating undercooked shellfish or consuming food that a sick person prepared.
Salmonella: Raw eggs and undercooked poultry are common sources of salmonella poisoning. Salmonella is responsible for the highest number of hospitalizations and deaths from food poisoning.
Staphylococcus aureus (staph): A staph infection occurs when people transfer the staph bacteria from their hands to food.
Clostridium perfringens: Raw meat or poultry, pre-cooked foods are common sources of clostridium. It can cause gastrointestinal (GI) symptoms (nausea, vomiting, abdominal pains, and diarrhea) within 6-24 hours. It generally lasts a day or two but can last weeks in some people.
Campylobacter: This common bacterial infection producing severe GI upset can linger for weeks. Usually, culprits are found in poorly processed meats or contaminated vegetables, milk, or water sources. The condition is generally self-limited and is rarely fatal.
Trichinella spiralis: This worm is found in raw or undercooked meats, particularly pork products.

RISK FACTORS

Whether you become ill after eating contaminated food depends on the organism, the amount of exposure, your age and your health. High-risk groups include:

Older adults. As you get older, your immune system may not respond as quickly and as effectively to infectious organisms as when you were younger.
Pregnant women. During pregnancy, changes in metabolism and circulation may increase the risk of food poisoning. Your reaction may be more severe during pregnancy. Rarely, your baby may get sick, too.
Infants and young children. Their immune systems haven't fully developed.
People with chronic disease. Having a chronic condition — such as diabetes, liver disease or AIDS — or receiving chemotherapy or radiation therapy for cancer reduces your immune response.

SYMPTOMS

Food poisoning symptoms vary with the source of contamination. Most types of food poisoning cause one or more of the following signs and symptoms:

Nausea
Vomiting
Watery or bloody diarrhea
Abdominal pain and cramps
Fever

Signs and symptoms may start within hours after eating the contaminated food, or they may begin days or even weeks later. Sickness caused by food poisoning generally lasts from a few hours to several days.

COMPLICATIONS

The most common serious complication of food poisoning is dehydration- a severe loss of water and essential salts and minerals. If you're a healthy adult and drink enough to replace fluids you lose from vomiting and diarrhea, dehydration shouldn't be a problem.

Infants, older adults and people with suppressed immune systems or chronic illnesses may become severely dehydrated when they lose more fluids than they can replace. In that case, they may need to be hospitalized and receive intravenous fluids. In extreme cases, dehydration can be fatal.

Some types of food poisoning have potentially serious complications for certain people. These include:

Listeria infection. Complications of a listeria food poisoning may be most severe for an unborn baby. Early in pregnancy, a listeria infection may lead to miscarriage. Later in pregnancy, a listeria infection may lead to stillbirth, premature birth or a potentially fatal infection in the baby after birth — even if the mother was only mildly ill. Infants who survive a listeria infection may experience long-term neurological damage and delayed development.
Escherichia coli (E. coli). Certain E. coli strains can cause a serious complication called hemolytic uremic syndrome. This syndrome damages the lining of the tiny blood vessels in the kidneys, sometimes leading to kidney failure. Older adults, children younger than 5 and people with weakened immune systems have a higher risk of developing this complication. If you're in one of these risk categories, see your doctor at the first sign of profuse or bloody diarrhea.

DIAGNOSIS

Food poisoning is often diagnosed based on a detailed history, including how long you've been sick, your symptoms and specific foods you've eaten. Your doctor will also perform a physical exam, looking for signs of dehydration.

Depending on your symptoms and health history, your doctor may conduct diagnostic tests, such as a blood test, stool culture or examination for parasites, to identify the cause and confirm the diagnosis.

For a stool test, your doctor will send a sample of your stool to a lab, where a technician will try to identify the infectious organism. If an organism is found, your doctor likely will notify your local health department to determine if the food poisoning is linked to an outbreak.

In some cases, the cause of food poisoning can't be identified.

TREATMENT

Treatment for food poisoning typically depends on the source of the illness, if known, and the severity of your symptoms. For most people, the illness resolves without treatment within a few days, though some types of food poisoning may last longer.

Treatment of food poisoning may include:

Replacement of lost fluids. Fluids and electrolytes- minerals such as sodium, potassium and calcium that maintain the balance of fluids in your body- lost to persistent diarrhea need to be replaced. Some children and adults with persistent diarrhea or vomiting may need hospitalization, where they can receive salts and fluids through a vein (intravenously), to prevent or treat dehydration.
Antibiotics. Your doctor may prescribe antibiotics if you have a certain kind of bacterial food poisoning and your symptoms are severe. Food poisoning caused by listeria needs to be treated with intravenous antibiotics during hospitalization. The sooner treatment begins, the better. During pregnancy, prompt antibiotic treatment may help keep the infection from affecting the baby.

Antibiotics will not help food poisoning caused by viruses. Antibiotics may actually worsen symptoms in certain kinds of viral or bacterial food poisoning. Talk to your doctor about your options.

Adults with diarrhea that isn't bloody and who have no fever may get relief from taking the medication loperamide (Imodium A-D) or bismuth subsalicylate (Pepto-Bismol). Ask your doctor about these options.

PREVENTION

To prevent food poisoning at home:

Wash your hands, utensils and food surfaces often. Wash your hands well with warm, soapy water before and after handling or preparing food. Use hot, soapy water to wash utensils, cutting boards and other surfaces you use.
Keep raw foods separate from ready-to-eat foods. When shopping, preparing food or storing food, keep raw meat, poultry, fish and shellfish away from other foods. This prevents cross-contamination.
Cook foods to a safe temperature. The best way to tell if foods are cooked to a safe temperature is to use a food thermometer. You can kill harmful organisms in most foods by cooking them to the right temperature. Cook ground beef to 160 F (71.1 C); steaks, roasts and chops, such as lamb, pork and veal, to at least 145 F (62.8 C). Cook chicken and turkey to 165 F (73.9 C). Make sure fish and shellfish are cooked thoroughly. Refrigerate or freeze perishable foods promptly- within two hours of purchasing or preparing them. If the room temperature is above 90 F (32.2 C), refrigerate perishable foods within one hour.
Defrost food safely. Don't thaw food at room temperature. The safest way to thaw food is to defrost it in the refrigerator. If you microwave frozen food using the "defrost" or "50% power" setting, be sure to cook it immediately.
Throw it out when in doubt. If you aren't sure if a food has been prepared, served or stored safely, discard it. Food left at room temperature too long may contain bacteria or toxins that can't be destroyed by cooking. Don't taste food that you're unsure about — just throw it out. Even if it looks and smells fine, it may not be safe to eat.

Food poisoning is especially serious and potentially life-threatening for young children, pregnant women and their fetuses, older adults, and people with weakened immune systems. These individuals should take extra precautions by avoiding the following foods:

Raw or rare meat and poultry
Raw or undercooked fish or shellfish, including oysters, clams, mussels and scallops
Raw or undercooked eggs or foods that may contain them, such as cookie dough and homemade ice cream
Raw sprouts, such as alfalfa, bean, clover and radish sprouts
Unpasteurized juices and ciders
Unpasteurized milk and milk products
Soft cheeses, such as feta, Brie and Camembert; blue-veined cheese; and unpasteurized cheese
Refrigerated pates and meat spreads
Uncooked hot dogs, luncheon meats and deli meats