Food Poisoning

What is food poisoning?

Food poisoning is an illness that you may get after eating food contaminated by some types of bacteria, parasites, and viruses.

How does it occur?

Bacteria:

Bacteria are all around you--on your hands, countertops, floor--everywhere. Eating a few bacteria usually will not hurt you. However, some types of bacteria in contaminated food can make you sick. Examples of bacteria that cause food poisoning are E. coli, Clostridium perfringens, Bacillus cereus, Staphylococcus, and Salmonella.

Many types of bacteria grow best in a warm, moist place. Food can be a great place for bacteria to grow if it is not properly cooled, stored, or heated. However, even if you cook and eat your food promptly, you can still get food poisoning. For example, bacteria can get into your cooked food if the cooked food touches an unwashed utensil or countertop that was used to prepare uncooked meat. That is why it is important to wash your hands, utensils, and countertops before and after you handle raw meat.

Food, especially beef, can be contaminated as it is prepared for sale to grocery stores. For example, a harmful type of E. coli bacteria might get into the food at the slaughterhouse or the butcher.

Salmonella food poisoning is common. It is caused most often by eating food containing raw eggs or undercooked chicken or turkey.

Botulism is a type of food poisoning caused by Clostridium botulinum. These bacteria may grow in places with no oxygen, such as sealed cans and vacuum-packed foods.

Viruses:

The viruses that commonly cause food poisoning are found in water that has been contaminated with human bowel movements. The viruses get into foods such as oysters, clams, and other shellfish. If you drink the water or eat the seafood raw or partially cooked, you may become ill.

Parasites:

Parasites can also cause food poisoning. The most common type of parasitic food poisoning is called trichinosis. Trichinosis is caused by roundworms in pork.

What are the symptoms?

Symptoms of food poisoning include:

• nausea
• vomiting
• diarrhea
• stomach pain
• fever (in some cases).

If you have botulism, you probably will not have a fever and the symptoms may also include:

• blurred vision
• fatigue
• dry mouth and throat.

Depending on the cause, you may start having symptoms hours to months after you eat contaminated food. The most common types of food poisoning cause symptoms in 30 minutes to 2 days. Some types of food poisoning by shellfish may take only a few minutes to cause symptoms.

How is it diagnosed?

Food poisoning is often suspected when several people become ill after eating the same food. Your health care provider will ask about your symptoms and the food you ate just before you became ill. Your provider may ask for samples of the food and may test one or more of your bowel movements.

How is it treated?

Treatment depends on how sick you are and what is causing the illness. Generally your health care provider will recommend rest, a special diet, and lots of fluids. Your provider may prescribe medicine to stop vomiting and stomach cramping. Antibiotics may be helpful for some types of food poisoning. If you have botulism, your provider may prescribe a medicine called an antitoxin.

How long will the effects last?

It usually takes about 1 to 5 days to recover fully from food poisoning.

If you are pregnant or over the age of 65, or if you have a chronic disease or weak immune system, you can become seriously ill from food poisoning. In such cases, it is especially important to contact your health care provider if you think you have food poisoning.

How can I take care of myself?

• Be cautious about taking nonprescription antidiarrheal medicines such as loperamide (Kaopectate or Imodium) or the prescription medicine Lomotil. These medicines can actually make you sicker, especially if the diarrhea is bloody. If you take one of these medicines, make sure you use only the dose recommended on the package. If you have chronic health problems, always check with your health care provider before you use any medicine for diarrhea.
• If you have a fever over 100°F (37.8°C), rest as much as you can. Ask your provider if you can take aspirin, acetaminophen, or ibuprofen to control your fever. (Anyone under age 21 who may have a viral illness should not take aspirin because aspirin increases the risk of Reye's syndrome.) After your temperature falls below 100°F, you may increase your activity, but don't do more than is comfortable for you.
• If you have cramps or stomach pain, it may help to put a covered hot water bottle or electric heating pad (set at low) on your stomach.
• If you have diarrhea or nausea, you may want to let your bowel rest for a few hours by drinking only clear liquids. Examples of clear liquids are water, weak tea, bouillon, apple juice, or sports drinks and other oral rehydrating solutions. You may also drink soft drinks without caffeine (such as 7 UP) after letting them lose some of their carbonation (go flat). It is important to drink small amounts (1 to 4 ounces) often so that you do not become dehydrated. Becoming dehydrated may be very dangerous, especially for children, older adults, and some people who have other medical problems. Suck on ice chips or Popsicles if you feel too nauseated to drink fluids.
• It is OK to keep eating as long as it does not seem to worsen diarrhea or stomach cramps. Foods that are easiest to digest are soft foods, such as bananas, cooked cereal, rice, plain noodles, gelatin, eggs, toast or bread with jelly, and applesauce. Avoid milk products and caffeine for a few days. Return to your normal diet after 2 or 3 days, but for several more days avoid fresh fruit (other than bananas), alcohol, greasy or fatty foods such as cheeseburgers or bacon, and highly seasoned or spicy foods. Avoid most fresh vegetables. Cooked carrots, potatoes, and squash are OK. If eating seems to worsen the diarrhea, let your bowel rest for a few hours by drinking just clear liquids.
• Call your health care provider right away if:
  • Your symptoms are getting worse instead of better.
  • You are pregnant or elderly or have a chronic illness or weakened immune system.
  • An older adult becomes listless, withdrawn, or inactive.
  • You have nervous system symptoms, such as tingling, weakness, or headache.
  • You have a high fever as well as other symptoms.

What can I do to prevent food poisoning?

Follow these guidelines to prevent food poisoning:

• Make sure the dairy products you eat and drink have been pasteurized.
• Throw away any cans that are bulging or leaking. Do not taste any foods that look or smell suspicious after you open the container. Remember also that contaminated foods can seem normal in appearance and smell.
• Wash your hands before you prepare, cook, or serve food and after you go to the bathroom or touch animals. Cover any sore or cut on your hands before preparing food. Use rubber gloves or cover the sore with a clean bandage.
• Rinse fresh vegetables and fruits before you eat or cook them.
• Wash cutting boards or any utensils used with raw meat before you use them with other foods. (It's best to have two cutting boards: one for meat and one for other foods.) Keep kitchen counters and other food preparation surfaces clean. Replace used dishcloths and kitchen towels with clean ones often.
• Thaw frozen poultry completely before you cook it. Thaw meat in the refrigerator or with a microwave. Do not let it stand at room temperature.
• Cook food thoroughly, especially meat, poultry, and leftovers. Pork should be heated to an internal temperature of at least 160°F (71°C). For whole chickens and turkeys a temperature of 180°F (82°C) is recommended for thigh meat and 170°F (77°C) for breast meat. Never partially cook meat or poultry and then finish cooking it later.
• Refrigerate leftover meat, seafood, dairy products, eggs, or poultry as soon as possible. Do not let it sit out of the refrigerator longer than 2 hours. Make sure your refrigerator maintains a temperature of 40°F (4°C) or lower.
• Make sure when you can foods at home that you sterilize the food completely by heating it in a pressure cooker at 250°F (121°C) for 30 minutes.

If you have food poisoning, you can help prevent spreading it to other people by avoiding unnecessary contact with others until your symptoms are gone. Wash your hands thoroughly with soap and very warm water after you use the restroom. Do not prepare food for other people. If you must prepare or serve food, wash your hands thoroughly before you cook or serve food and before you eat. Do not work as a food handler in restaurants, dining halls, or grocery stores until your diarrhea is completely gone.

You can get more information on food poisoning and safe food handling from:

• American College of Gastroenterology (ACG). Call 703-820-7400 or visit the Web site at http://www.acg.gi.org.
• Center for Food Safety and Applied Nutrition, US Food and Drug Administration (FDA). The Web site is http://www.cfsan.fda.gov.
• Food Safety and Inspection Service, US Department of Agriculture. Call 800-535-4555 or visit the Web site at http://www.fsis.usda.gov.