Filed under: Digestive Health
Food poisoning, also called food-borne illness, is illness caused by eating contaminated food. Infectious organisms — including various 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 during its processing or production. Contamination can also occur at home if food is incorrectly handled or cooked.
Food poisoning symptoms often include nausea, vomiting or diarrhea, which can start just hours after eating contaminated food. Most often, food poisoning is mild and resolves without treatment. But some cases are severe, requiring hospitalization.
Food poisoning symptoms vary with the source of contamination. Most types of food poisoning cause one or more of the following signs and symptoms:
Signs and symptoms may start within hours after eating the contaminated food, or they may begin days or possibly even weeks later. Sickness caused by food poisoning generally lasts from one to 10 days.
When to see a doctor
If you experience any of the following signs or symptoms, seek medical attention.
If you suspect food poisoning, also contact your local health department. Your report can help the health department identify a potential outbreak and may help prevent other people from getting sick. You may need to describe what you ate, where got the food you think is making you sick, when you got sick and your symptoms.
Contamination of food can happen at any point during its production: growing, harvesting, processing, storing, shipping or preparing. Cross-contamination — the transfer of harmful organisms from one surface to another — is often the cause. This is especially troublesome for raw, ready-to-eat foods, such as salads or other produce. Because these foods aren't cooked, harmful organisms aren't destroyed before eating and can cause food poisoning.
Many bacterial, viral or parasitic agents cause food poisoning. The following table shows some of the possible contaminants, when you might start to feel symptoms and common ways the organism is spread.
|Contaminant||Onset of symptoms||Foods affected and means of transmission|
|Campylobacter||2 to 5 days||Meat and poultry. Contamination occurs during processing if animal feces contact meat surfaces. Other sources include unpasteurized milk and contaminated water.|
|Clostridium botulinum||12 to 72 hours||Home-canned foods with low acidity, improperly canned commercial foods, smoked or salted fish, potatoes baked in aluminum foil and other foods kept at warm temperatures for too long.|
|Clostridium perfringens||8 to 16 hours||Meats, stews and gravies. Commonly spread when serving dishes don't keep food hot enough or food is chilled too slowly.|
|Escherichia coli (E. coli) O157:H7||1 to 8 days||Beef contaminated with feces during slaughter. Spread mainly by undercooked ground beef. Other sources include unpasteurized milk and apple cider, alfalfa sprouts and contaminated water.|
|Giardia lamblia||1 to 2 weeks||Raw, ready-to-eat produce and contaminated water. Can be spread by an infected food handler.|
|Hepatitis A||28 days||Raw, ready-to-eat produce and shellfish from contaminated water. Can be spread by an infected food handler.|
|Listeria||9 to 48 hours||Hot dogs, luncheon meats, unpasteurized milk and cheeses, and unwashed raw produce. Can be spread through contaminated soil and water.|
|Noroviruses (Norwalk-like viruses)||12 to 48 hours||Raw, ready-to-eat produce and shellfish from contaminated water. Can be spread by an infected food handler.|
|Rotavirus||1 to 3 days||Raw, ready-to-eat produce. Can be spread by an infected food handler.|
|Salmonella||1 to 3 days||Raw or contaminated meat, poultry, milk or egg yolks. Survives inadequate cooking. Can be spread by knives, cutting surfaces or an infected food handler.|
|Shigella||24 to 48 hours||Seafood and raw, ready-to-eat produce. Can be spread by an infected food handler.|
|Staphylococcus aureus||1 to 6 hours||Meats and prepared salads, cream sauces and cream-filled pastries. Can be spread by hand contact, coughing and sneezing.|
|Vibrio vulnificus||1 to 7 days||Raw oysters and raw or undercooked mussels, clams and whole scallops. Can be spread through contaminated seawater.|
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:
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. But 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:
If you or your child needs to see a doctor, you'll likely see your primary care provider first. If there are questions about the diagnosis, your doctor may refer you to an infectious disease specialist.
What you can do
Your time with your doctor is often limited, so preparing a list of questions will help you make the most of your time together. Some questions you might want to ask your doctor or your child's doctor include:
What to expect from your doctor
Some questions the doctor may ask include:
What you can do in the meantime
Drink plenty of fluids. Stick with bland foods to reduce stress on your digestive system. If your child is sick, follow the same approach — offer plenty of fluids and bland food. If you're breast-feeding or using formula, continue to feed your child as usual. Ask your child's doctor if giving your child an oral rehydration fluid, such as Pedialyte, is appropriate. Medications that help ease diarrhea generally aren't recommended because in some cases, they can make food poisoning more severe and longer lasting.
Food poisoning is often diagnosed based on a detailed history, including how long you've been sick, characteristics of 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 culture, your doctor will ask for a stool sample and send it to a laboratory, where a technician will try to grow and identify the infectious organism. In some cases, the cause of the food poisoning cannot be identified.
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 a week or more.
Treatment of food poisoning may include:
Food poisoning often improves on its own within 48 hours. To help keep yourself more comfortable and prevent dehydration while you recover, try the following:
Here are steps you can take to prevent food poisoning at home:
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: