Food poisoning is caused by bacteria and, sometimes, viruses or other germs. They can get into the food we eat or the liquids we drink. We can't taste, smell, or see these germs (at least not without a microscope). But even though they're tiny, they can have a powerful effect on the body.
Once the germs that cause food poisoning get into our systems, some of them release toxins. These toxins are poisons (the reason for the name "food poisoning"), and they can give a person diarrhea and vomiting.
Most of the time, doctors use "food poisoning" to describe an illness that comes on quickly after eating contaminated food. People often get diarrhea or start throwing up within a few hours after being infected. The good news is, food poisoning usually goes away quickly too. Most people recover in a couple of days with no lasting complications.
In a few cases, food poisoning can be severe enough to require a visit to the doctor or hospital. When people need medical treatment for food poisoning, it's often because of dehydration. Getting dehydrated is the most common serious complication of food poisoning.
When people eat or drink something that's contaminated with germs, they can get sick with food poisoning. Often, people get food poisoning from animal-based foods — like meat, poultry, eggs, dairy products, and seafood. But unwashed fruits, vegetables, and other raw foods also can get contaminated and make people sick. Even water can cause food poisoning.
Foods and liquids can be contaminated at lots of different points in the food preparation, storage, and handling process. For example:
People with health conditions (like chronic kidney disease) or weakened immune systems are more at risk of getting ill from food poisoning than people who are in good health.
A number of microorganisms can cause food poisoning. Some of the most common culprits are:
Salmonella. Salmonella bacteria are the leading cause of food poisoning in the United States. These bacteria usually get into foods when they come into contact with animal feces. The main causes of salmonella poisoning are eating dairy products, undercooked meat, and fresh produce that hasn't been washed well.
E. coli (Escherichia coli). E. coli bacteria, too, typically get into food or water when they come into contact with animal feces. Eating undercooked ground beef is the most common reason why people in the United States get E. coli poisoning.
Listeria. These bacteria are mostly found in unpasteurized dairy products, smoked seafood, and processed meats like hot dogs and luncheon meats. Listeria bacteria also can contaminate fruits and vegetables, although that's less common.
Campylobacter. These bacteria most commonly infect meat, poultry, and unpasteurized milk. Campylobacter also can contaminate water. As with other kinds of bacteria, these usually get into foods through contact with infected animal feces.
Staphylococcus aureus. These bacteria can be found in meats, prepared salads, and foods made with contaminated dairy products. S aureus bacteria can spread through hand contact, sneezing, or coughing. That means the infection can be transmitted by people who prepare or handle food.
Shigella. Shigella bacteria can infect seafood or raw fruits and vegetables. Most of the time the bacteria are spread when people who prepare or handle food don't wash their hands properly after using the bathroom.
Hepatitis A. People mostly get this virus from eating raw shellfish or foods that have been handled by someone who is infected. It can be hard to pinpoint the source of an infection because people may not get sick for 15 to 50 days afterward.
Noroviruses. These viruses usually contaminate food that's been prepared by an infected handler.
How food poisoning shows up depends on the germ that caused it. Sometimes a person will start to feel sick within an hour or two of eating or drinking contaminated food or liquid. Other times, symptoms may not appear for a number of weeks. In most cases, symptoms will clear up within 1 to 10 days.
Most of the time, someone with food poisoning will notice:
In rare cases, food poisoning can make someone feel dizzy, have blurry vision, or notice tingling in the arms. In very rare cases, the weakness that sometimes goes along with food poisoning will cause trouble breathing.
Certain types of infectious microorganisms, including Listeria and E. coli, can cause potentially dangerous heart, kidney, and bleeding problems.
Most cases of food poisoning don't require medical attention, but some do. The most common serious problem that happens with food poisoning is dehydration. If you're healthy, you're not likely to get dehydrated as long as you drink enough fluids to replace what you've lost through throwing up or diarrhea.
Call a doctor if you have any of these problems:
You'll also want to let your mom or dad know if you start having signs of dehydration. They may want to call the doctor. Signs of dehydration include:
If you've recently been to a foreign country and start having diarrhea or other stomach problems, it's also a good idea to call your doctor.
Food poisoning (especially dehydration) can be more serious for people with weakened immune systems or health conditions. If you have a health condition like kidney problems or sickle cell disease, call your doctor as soon as you notice signs that could be food poisoning. Pregnant women should also let their doctors know if they get food poisoning as some germs can affect the unborn child.
A doctor will ask about what you have eaten recently, how long you've been sick, and what kinds of problems you're having. The doctor will also examine you.
In some cases, doctors may take a sample of your blood, stool, or urine and send it to a lab for analysis. This will help the doctor find out which microorganism is causing the illness.
Most of the time, food poisoning runs its course and people get better on their own. Occasionally, though, doctors prescribe antibiotics to treat more severe types of bacterial food poisoning. If dehydration is severe, some people may need to be treated in a hospital with intravenous (IV) fluids.
Food poisoning usually goes away on its own in a few days. You can do a few things to take care of yourself:
To reduce your risk of food poisoning, follow these tips:
If you get sick with food poisoning, it's a good idea to get in touch with your local health department. If they can pinpoint what caused the condition, they may be able to stop a potential outbreak and keep others from getting sick as well.
Reviewed by: J. Fernando del Rosario, MD
Date reviewed: March 2012
|Centers for Disease Control and Prevention (CDC) The CDC (the national public health institute of the United States) promotes health and quality of life by preventing and controlling disease, injury, and disability.|
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|Why Should I Care About Germs? Germs are tiny organisms that can cause disease - and they're so small that they can creep into your system without you noticing. Find out how to protect yourself.|
|Gastrointestinal Infections and Diarrhea Nearly everybody gets diarrhea every once in a while, and it's usually caused by gastrointestinal infections. It's nothing to be embarrassed about. Read this article to learn more.|
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|Shigellosis Shigellosis is an intestinal infection caused by bacteria that can give a person bloody diarrhea and cause intestinal pain. Good hand washing is the best way to prevent shigellosis.|
|Salmonellosis People often think of salmonellosis as food poisoning, but food is only one way the bacteria Salmonella can be spread.|
|Food Safety Learn why food safety is important and how you can avoid the spread of bacteria when you are buying, preparing, and storing food.|
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