Food Poisoning

Overview

What is food poisoning?

Food poisoning, or foodborne illness, occurs when you eat contaminated food. Contaminated means it’s infected with a toxic organism, such as a bacteria, fungus, parasite or virus. Sometimes the toxic byproducts of these organisms cause food poisoning.

When you eat something toxic, your body reacts to purge the toxins. You may purge through vomiting, diarrhea, fever or all of these. The uncomfortable symptoms of food poisoning are your body’s way of working to return to health. It usually works in a day or two.

What is the difference between food poisoning and stomach flu?

Food poisoning and stomach flu are both gastrointestinal infections. They both cause gastroenteritis, which is inflammation of your stomach and small intestine. Gastroenteritis is the sign that your immune system has been activated to remove the infection.

Many of the same viral, bacterial and other infections can cause food poisoning or stomach flu, resulting in the same symptoms. The main difference is that foodborne illness comes from food, whereas you may catch a stomach bug in a variety of other ways.

How can you tell if it’s food poisoning or something else?

It can be hard to tell where an infection came from, especially if it took some days to develop symptoms. You may be able to trace it back to something you ate if it was something typically associated with food poisoning, or if you were with someone else who also got sick.

How common is food poisoning?

It’s very common. According to the CDC, about 48 million people a year experience some type of food poisoning in the United States. Most cases are not serious. However, about 3,000 people a year die from complications related to foodborne illness.

Who gets food poisoning?

Anyone can get food poisoning if they eat contaminated food. But some people are more likely to get sick from contamination than others. It has to do with how much toxicity your body can normally tolerate without getting sick.

Our immune systems constantly fend off infections without our knowing about it. Even with sanitary food handling practices, there is usually a small amount of contamination in our food. It becomes “poisonous” when our immune systems reach their threshold.

Who is most at risk from foodborne illness?

You may be more likely to get sick from food poisoning, or have a more severe reaction to food poisoning, if your immune system is not as strong as average. Temporary things can impact your immunity, as well as longer-term conditions, such as:

  • Age. Children under the age of 5 have immature immune systems. Mature immune systems begin to decline after the age of 65.
  • Pregnancy. Pregnancy is demanding on the body, leaving you with fewer resources than usual to fight off infections.
  • Chronic illnesses. Many chronic conditions can affect your immunity, including infections, cancer, immunodeficiency diseases and autoimmune diseases.
  • Medications. Corticosteroids and immunosuppressants can repress your immune system and make you more prone to illness.

Symptoms and Causes

How do you get food poisoning?

You get it by eating or drinking contaminated food, water or other beverages. Food can become contaminated at any stage of production, from harvesting to storage to cooking or preparation. Contamination occurs when food is not:

  • Fresh.
  • Washed well.
  • Handled in a sanitary way.
  • Cooked to a safe internal temperature.
  • Held at proper temperatures.
  • Refrigerated or frozen promptly.

Food poisoning occurs everywhere, but it’s especially easy to get it when traveling abroad, where you might encounter infectious pathogens that you wouldn’t at home. When you get it this way, it’s sometimes called traveler’s diarrhea.

What types of contaminants cause food poisoning?

Food and water may be contaminated by:

  • Bacteria.
  • Viruses.
  • Parasites.
  • Funguses.
  • Toxins.
  • Chemicals.

There are more than 250 specific types of food poisoning. Some of the most common causes include:

  • Salmonella: Raw eggs and undercooked poultry are common sources of salmonella poisoning. It can also occur from beef, pork, vegetables and processed foods containing these items. Salmonella is the most common bacterial cause of food poisoning in the U.S. and is responsible for the highest number of hospitalizations and deaths from food poisoning.
  • E. coli: Usually found in undercooked meat and raw vegetables, E. coli bacteria produces a toxin that irritates your small intestine. The Shiga toxin is what causes foodborne illness.
  • Listeria: Bacteria in soft cheeses, deli meats, hot dogs and raw sprouts can cause an infection called listeriosis, which is especially dangerous for pregnant women.
  • Norovirus: You can get norovirus by eating undercooked shellfish, leafy greens, fresh fruits or by consuming food that a sick person prepared. This is the virus most commonly associated with stomach flu.
  • Hepatitis A. Viral hepatitis A can be spread through shellfish, fresh produce or water and ice contaminated by stool. It’s not a chronic infection like other hepatitis viruses, but it can affect your liver.
  • Staphylococcus aureus (staph): A staph infection occurs when people transfer the staph bacteria from their hands to food. Foods that are often implicated are meats, poultry, milk and dairy products, salads, cream-filled baked goods, and sandwich fillings. The bacteria can affect many parts of your body.
  • Campylobacter: This common bacterial infection producing severe GI upset can linger for weeks. Usually, culprits are undercooked poultry, meat or eggs, poorly processed meats, contaminated vegetables and raw (unprocessed) milk or water sources. It’s also spread by cross-contamination. The condition is generally self-limited, causes bloody diarrhea and is rarely fatal.
  • Shigella (shigellosis): Shigella bacteria is most typically found in uncooked vegetables, shellfish and cream or mayonnaise-based salads (tuna, potato, macaroni, chicken). It can cause blood or mucus in your diarrhea, which is why the infection is sometimes called bacillary dysentery.

Is food poisoning contagious?

The infection can spread from you to another person if they come into contact with your germs. Germs can spread through tiny particles of vomit or poop that linger on surfaces or on fingers and then transfer to another person’s food or mouth.

What are the 6 signs of food poisoning?

The most common symptoms of food poisoning include:

How quickly does food poisoning kick in?

It depends on the type of infection. Some of the most common bacterial infections take hold within a few hours. Others need time to incubate in your system before they become toxic. Some infections may take a few days, and some can take a few weeks.

How long does food poisoning last?

Most of the time, food poisoning passes within 12 to 48 hours. That’s how long it takes for a healthy body to purge the infection. It may last longer if you have a weakened immune system, or if you have a parasite that needs to be treated with antibiotics.

Diagnosis and Tests

How is food poisoning diagnosed?

Your healthcare provider will ask you about your symptoms and what you’ve had to eat and drink recently. If you have particular symptoms, they may want to take a stool sample or give you a blood test to check for particular parasites or bacteria.

Management and Treatment

How is food poisoning treated?

In most cases, you can manage food poisoning at home by simply staying hydrated. You lose a lot of fluids through diarrhea, vomiting, and fever. Staying hydrated is the most important thing you can do to support your body while it does its work.

Hydration formulas such as Pedialyte™ can be helpful when you’re sick. These formulas help fluids stay in your body longer. If you or your child are having trouble keeping fluids down or showing signs of dehydration, you might need to go to the hospital for IV fluids.

Should I take medication for food poisoning?

Certain types of infections may require antibiotics. Your healthcare provider will work to determine if you have one of these types. Most of the time, antibiotics aren’t necessary, and often they won’t help. Some types of infections may even worsen with antibiotics.

Healthcare providers don’t typically prescribe antidiarrheal medications for food poisoning because they can prolong the illness. However, you may be able to relieve some of your symptoms with over-the-counter bismuth subsalicylate (Pepto Bismol®).

What should I eat and drink while I’m sick with food poisoning?

You may want to let your stomach settle for a while before introducing food or drinks. Try sucking on ice chips to stay hydrated without overwhelming your stomach. Fruit juice popsicles or gelatin are other options that can offer you a little sugar for energy.

When you feel prepared to begin eating again, start with small bites of bland foods. Some broth and crackers or toast would be a great choice. The sodium and water content in the broth can help you rehydrate, while the crackers add bulk to your stools.

Prevention

How can food poisoning be prevented?

Safe food handling practices are the most important way to prevent foodborne illness. Those who harvest, handle and prepare food need to be vigilant at every stage of the process to prevent contamination. For example:

  • Clean: Wash raw produce well in clean, sanitary water. Wash your hands and utensils before using them to prepare food. Wash and disinfect all surfaces that your food will touch, including cutting boards, countertops and plates.
  • Separate: Avoid cross-contamination by separating raw meats and eggs from fresh produce or other food items. Meat products may carry germs that will be destroyed when cooked at proper temperatures. If those germs transfer to something that won’t be cooked, they may survive and contaminate that food item.
  • Cook: Take care to cook meats and seafood thoroughly to the proper temperatures to kill germs. Whole cuts of meat can be pink on the inside if they are well-seared on the outside. Ground meats need to be thoroughly cooked with no pink left. Fish should be opaque and not translucent and easy to flake with a fork.
  • Chill: Refrigerate or freeze prepared foods within two hours of cooking to keep bacteria from breeding. If foods contain gravy, sauces, mayonnaise or creams, then make sure they have held at proper temperatures while still serving them. Check your refrigerated foods for microbe growth such as mold. Throw out dairy products if they have passed their expiration dates or have an “off” smell.
  • Community: Your public health department makes an effort to control food poisoning by informing citizens of possible outbreaks. Pay attention to public announcements of food recalls. If you’ve acquired food poisoning, report it.

Outlook / Prognosis

What is the outlook for people who have food poisoning?

Most people will recover without intervention in a day or two. If you or someone in your care has a particularly severe reaction to food poisoning, you might need medical intervention. The most common reason for this is dehydration, especially in children.

What are the possible complications associated with food poisoning?

While complications from food poisoning are rare, they can be severe and, in some cases, even fatal. Severe dehydration is the most common risk, but some specific types of infections can cause other specific complications. For example:

Living With

When should I call my healthcare provider about food poisoning?

Call your healthcare provider if you are pregnant or breastfeeding, or if you are caring for a child who is having trouble keeping fluids down. Children become dehydrated more easily than we do. Call if you or your child have any unusual symptoms, such as:

  • Persistent, high fever (over 102 F).
  • Bloody diarrhea or vomit.
  • Dark urine or lack of urine.
  • Blurred vision.
  • Delirium or confusion.
  • Dizziness or lightheadedness.

When can you return to work or school if you have had food poisoning?

Stay home for at least 48 hours after you have had diarrhea or vomited. Stay home for at least 24 hours after a fever. Make sure to let your school or workplace know about the infection, especially if you or your child were infected while you were there.

A note from Cleveland Clinic

Even in modern, developed nations where food handling practices are relatively sanitary, food poisoning still commonly occurs. You may be even more at risk if you travel abroad. For the most part, our immune systems are well-equipped to deal with the occasional infection.

However, certain infections can cause serious side effects, especially in the more vulnerable among us. If you are concerned or immunocompromised, or if you have severe or unusual symptoms, don't hesitate to see your healthcare provider for testing and treatment.

Last reviewed by a Cleveland Clinic medical professional on 06/15/2022.

References

  • Centers for Disease Control and Prevention. Food Safety. (https://www.cdc.gov/foodsafety/index.html) Accessed 6/15/2022.
  • FoodSafety.gov. Food Poisoning. (https://www.foodsafety.gov/food-poisoning) Accessed 6/15/2022.
  • National Institute of Diabetes and Digestive and Kidney Diseases. Food Poisoning. (https://www.niddk.nih.gov/health-information/digestive-diseases/food-poisoning) Accessed 6/15/2022.
  • National Library of Medicine. Food Poisoning. (https://medlineplus.gov/ency/article/001652.htm) Accessed 6/15/2022.

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