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What is Food Poisoning?

Food Poisoning (or foodborne illness) is an infection or irritation of the gastrointestinal (GI) tract caused by food or beverages that contain harmful bacteria, parasites, viruses, or chemicals.

Common foodborne illness symptoms include vomiting, diarrhea, abdominal pain, fever, and chills. Most foodborne illnesses are acute, meaning they happen suddenly and last a short time, and most people recover on their own without treatment.

Occasionally, food poisoning may lead to more serious complications. Each year, an estimated 48 million  (1 in 6) people in the United States experience a foodborne illness. Foodborne illnesses cause 128, 000 hospitalizations and about 3,000 deaths in the United States annually.

What you should know

Recognizing the symptoms of foodborne illness is important when you or a loved one are experiencing discomfort from vomiting, diarrhea or abdominal pain. Keep in mind that foodborne illnesses often happen suddenly and have a short duration, with most healthy people recovering on their own and without treatment.

In foodborne events, symptoms typically occur within 6 to 72 hours after consuming food or beverages that may have been contaminated. Symptoms can range from mild to serious and can last from a few hours to several days. Keep in mind that symptoms can appear in as little as a few hours or weeks later.


Some symptoms of foodborne illness are dependent on the type of microorganism present, and can range from mild to serious and last from a few hours to several days

Many foodborne illnesses share common symptoms including:
                   • Vomiting
                   • Diarrhea or bloody diarrhea
                   • Abdominal pain
                   • Fever
                   • Chills

Additionally ...

In addition to the standard gastrointestinal symptoms (vomiting, diarrhea, abdominal pain, cramping) that are associated with foodborne illnesses, you should also determine whether the individual is suffering from any of the following: 
                    • fever and chills
                    • bloody diarrhea
                    • nausea
                    • aching joints
                    • back pain and fatigue
                    • dizziness

The toxins produced by Botulism (C. botulinum) affect the nervous system, causing symptoms such as
                    • headache
                    • tingling or numbness of the skin
                    • blurred vision
                    • weakness
                    • dizziness
                    • paralysis

*Risk Factors

Foodborne pathogens do not always produce symptoms or disease in every person.

Often, our bodies can tolerate pathogenic bacteria, viruses, protozoa and parasites in the GI tract because we have numerous defense mechanisms to guard against these types of illnesses.

However, because of their immature immune systems, babies and young children are at higher risk and should be closely monitored for rapid increases in symptoms. Erring on the side of caution is a good practice, and keeping children hydrated with water and electrolytes is a necessity, especially if they are experiencing vomiting or bouts of diarrhea.

Any changes in condition should be immediately checked out by a qualified healthcare professional.

In addition to children, other individuals with compromised immune systems such as older adults, pregnant women, and persons with HIV, cancer, or other chronic health concerns should also be closely monitored.


The majority of foodborne illness is caused by certain strains of bacteria and viruses. Parasites and chemicals may also cause foodborne illness.


Harmful bacteria may already be present in foods when they are purchased. Raw foods including meat, poultry, fish and shellfish, eggs, unpasteurized milk and dairy products, and fresh produce often contain bacteria that cause foodborne illness. This contamination can occur at any time during growth, harvesting or slaughter, processing, storage, and shipping of food.

Foods may also be contaminated with bacteria during food preparation in a restaurant or home kitchen. If hands, kitchen utensils, cutting boards, and other kitchen surfaces that come into contact with raw food are not washed, cross-contamination may occur.

When food is stored incorrectly, it gives bacteria the opportunity to multiply; room temperature (between 40º and 140ºF) is an ideal condition for bacteria to grow. Refrigerated food items should be kept at 40ºF or below, while hot foods should be kept at 140ºF or above.

Refrigeration can prevent bacteria from growing, and freezing food can further slow or even stop this growth. However, bacteria in refrigerated or frozen foods become active again when food is brought to room temperature, so these foods should be thoroughly cooked to kill any harmful bacteria.

More Bacteria


Viruses that cause foodborne illness can be spread by the stool and vomit of those already infected. Infected persons may contaminate food and drinks if proper hygiene is not adhered to during food preparation.

Viruses can also be spread through the use and/or ingestion of contaminated water or by ingestion of fish or shellfish grown in contaminated water.

More Viruses


Parasites are spread through water that has been contaminated with the stools of infected animals or humans.

Infected persons may contaminate food and drinks if proper hygiene is not adhered to during food preparation.

Additionally, foods that come into contact with contaminated water during growth or preparation can become contaminated with these parasites.

More Parasites


Fish or shellfish may feed on algae that produce toxins, leading to high concentrations of these toxins in their flesh.

Some types of fish may be contaminated with bacteria that produce toxins if they are not properly refrigerated before they are cooked or served.

Certain types of wild mushrooms also contain poisonous compounds. In addition, unwashed fruits and vegetables can contain high concentrations of pesticides.

More Chemicals

Foods Commonly Associated with Foodborne Illness

Foodborne illnesses arise from a variety of pathogens, but many cases are linked to foods that were unsanitary and contaminated at their source. If you or your loved one are experiencing the symptoms of foodborne illness, take a moment to review these common sources of infection.

Illnesses can come from a variety of sources, and this list is a good place to start narrowing down possible sources of illness.

Fruits + Vegetables

Fruits and vegetables can be contaminated when grown in fields that have been fertilized with animal waste. Additionally, if they have not been properly washed, or washed with contaminated water, there is also the risk of illness.

When consuming raw fruits and vegetables, it’s a good health practice to thoroughly wash all produce (including produce from which skin or rind will be removed) under running water just before eating, cutting, or cooking, even if purchased from trusted sources. A produce brush can be used under running water to clean fruits and vegetables with firm skin.

Raw Sprouts

Sprouts, like other types of produce, are often served raw in salads, sandwiches and even eaten on their own. Unlike other produce though, sprouts are grown in the kind of warm, humid conditions in which bacteria can thrive, and rapidly grow. To completely remove the risk of contamination from sprouts, they must be thoroughly cooked until steaming hot throughout.

Anyone with a compromised immune system such as a child, pregnant woman, or older adults, should completely avoid eating raw sprouts. Keep in mind that there is no smell test for raw produce or sprouts, so it’s imperative that food safety best practices be used when consuming these types of products.

Unpasteurized Juices and Ciders

We recommend avoiding all unpasteurized juices and ciders. Consuming unpasteurized juice or cider can lead to illness if they are contaminated.

Contamination can occur as a result of the way the fruit was grown and handled or the way the juice was processed.

Pasteurization, a technique used to kill contaminates is the process where the liquid is heated to a temperature of 145°F for a half hour, or 161°F for 15 seconds.

Raw juices are juices that have not been pasteurized, and carry a greater risk of pathogen contamination.

Human to Human Contamination

Any food item that has been handled by a person who is experiencing symptoms such as diarrhea, vomiting or fever can be considered suspect. For example, if an infected person prepares salad, cuts fruit or any product that is considered “ready to eat” without further cooking/heating, it can lead to contamination.

To decrease the risk, food must not be handled by persons who are showing signs of illness, or have recently been ill. Proceed with caution.

Raw Foods of Animal Origin

Consuming foods of animal origin, including meat, poultry, fish and shellfish as well as raw eggs, raw or undercooked meat and fish, or raw (unpasteurized) milk or milk products such as hard and soft cheeses, ice cream, yogurt, etc. always pose a risk. If these sources of protein have not been cooked to a safe internal temperature there is always a risk of contamination.

We recommend completely avoiding unpasteurized (raw) dairy products.


Foodborne illnesses can cause dehydration, hemolytic uremic syndrome (HUS), and other complications. Acute foodborne illnesses may also lead to chronic health problems or even death.

When someone does not drink enough fluids to replace those that are lost through vomiting and diarrhea, dehydration can result. Severe dehydration may require intravenous fluids and hospitalization. Untreated severe dehydration can cause serious health problems such as organ damage, shock, or coma. Infants, children, older adults, and people with weak immune systems have the greatest risk of becoming dehydrated.

Signs of dehydration include:

  •          ● Excessive thirst
  •          ● Infrequent urination
  •          ● Dark-colored urine
  •          ● Lethargy, dizziness, or faintness
  •          ● Dry mouth and tongue
  •          ● Lack of tears when crying
  •          ● No wet diapers for 3 hours or more
  •          ● High fever
  •          ● Unusually cranky or drowsy behavior
  •          ● Sunken eyes, cheeks, or soft spot in the skull
Hemolytic uremic syndrome (or HUS) is a rare disease that primarily affects children younger than 10. HUS develops when E. coli bacteria lodged in the digestive tract make toxins that enter the bloodstream. The toxins start to destroy blood cells that aid in clotting and the lining of the blood vessels. Symptoms of HUS (including irritability, paleness, and decreased urination) may develop up to a week after E. coli symptoms appear. HUS may lead to acute renal failure and negatively affect other organs and the central nervous system.

In the United States, E. coli O157:H7 infection is the most common cause of HUS, with a recent study showing that about 6 percent of people with E. coli O157:H7 infections develop it. Infection with other strains of E. coli, other bacteria, and viruses may also cause HUS. Children younger than age 5 are most at risk for developing HUS, but females and people age 60 and older also have an increased risk.

Most people who develop HUS recover with treatment. Research shows that in the United States between 2000 and 2006, fewer than 5 percent of people who developed HUS died of the disorder, with older adults having the highest mortality rate.* However, some who recover from HUS earlier in life develop chronic complications, including kidney problems, high blood pressure, and diabetes.

*Gould HL, Demma L, Jones TF, et. al. Hemolytic uremic syndrome and death in persons with Escherichia coli O157:H7 infection, Foodborne Diseases Active Surveillance Network sites, 2000–2006. Clinical Infectious Diseases. 2009:49(10):1480–1485.

~ Paralysis of the muscles that control breathing from the toxin produced by Clostridium botulinum and certain chemicals in fish and seafood.

~ Spontaneous abortion or stillbirth in pregnant women caused by Listeria monocytogenes infections.

~ Chronic disorders, including Reactive Arthritis from Campylobacter jejuni and Salmonella infections, Irritable Bowel Syndrome (IBS), and Guillain-Barré Syndrome, a disorder characterized by muscle weakness or paralysis,thought to occur after foodborne illnesses caused by bacteria, most commonly Campylobacter jejuni (C.jejuni) .

~ Possible increased risks of high blood pressure, kidney problems, and cardiovascular disease from E. coli O157:H7 infections.

People with any of the following symptoms should see a health care provider immediately:

  •       ● Signs of dehydration
  •       ● Prolonged vomiting that prevents keeping liquids down
  •       ● Diarrhea for more than 2 days in adults or for more than 24 hours in children
  •       ● Severe pain in the abdomen or rectum
  •       ● Fever higher than 101 degrees F
  •       ● Stools containing blood or pus
  •       ● Stools that are black and tarry
  •       ● Signs of nervous system failure
  •       ● Signs of HUS (Hemolytic Uremic Syndrome)

If you believe that you may have consumed harmful bacteria, parasites, viruses or chemicals from a public event, restaurant or commercial product, you should immediately contact your local health department.

The Centers for Disease Control and Prevention (CDC) has set up national [1]FoodCORE centers in nine states who, besides taking interviews from SSL (Salmonella, STEC, Listeria) and other pathogen victims, offer Whole Genome Sequencing (WGS) and reporting systems for outbreak surveillance.

To report a major illness,[2]you can also call the CDC, who has received 4 million such inquiries since 2005:

800-CDC-INFO (800-232-4636) TTY 888-232-6348

Monday – Friday 8:00 a.m. – 8:00 p.m. Eastern In English or Spanish

[1] Foodborne Diseases Centers for Outbreak Response Enhancement

Doctor with a stethoscope. Telehealth conference.


Health care providers may ask about symptoms, foods and beverages recently consumed, and medical history and also perform a physical examination in order to diagnose a foodborne illness.

In addition, diagnostic tests including a stool culture or a culture of a sample of vomit or suspected food (if available) may be performed.

A health care provider may perform additional medical tests to rule out diseases and disorders that cause symptoms similar to those of foodborne illnesses


The most common treatment for mild cases of foodborne illness is replacing lost fluids and electrolytes to prevent dehydration.

Over-the-counter medications may help stop diarrhea in adults, however, these medications should not be used by people with bloody diarrhea, as this may be a sign of bacterial or parasitic infection. If diarrhea is caused by bacteria or parasites, over-the-counter medications may prolong the problem. Medications to treat diarrhea in adults can be dangerous for infants and children and should only be given with a health care provider’s guidance.

If the specific cause of the foodborne illness is diagnosed, a health care provider may prescribe medications, such as antibiotics, to treat the illness. Hospitalization may be required to treat more severe cases of foodborne illness.

More on Symptoms + Treatment


Foodborne illnesses can be prevented by properly storing, cooking, cleaning, and handling foods:

Hands: Palms and fingers, back of hands, wrists, between fingers and thumbs, under and around all fingernails should be washed at least 20 seconds with warm, soapy water before and after handling raw meat, poultry, fish, shellfish, produce, or eggs, as well as after using the bathroom, changing diapers, or touching animals.

● Perishable Foods: To keep raw and cooked perishable foods safe, refrigerate or freeze them promptly. Store refrigerated food at 40ºF (or lower) and frozen food at a minimum 0ºF. Thaw frozen food in the refrigerator or in the microwave, immediately followed by cooking.

● Safe Temperature: Use a meat thermometer to ensure foods are cooked to the a safe internal temperature. We recommend using a digital thermometer because they’re easy to use and keep clean. Click here for a chart of safe internal cooking temperatures for food.

● Produce Rules: Wash fruits and vegetables under running water just before eating, cutting, or cooking, even if you’re discarding the rind or skin. A produce brush can be used under running water to clean fruits and vegetables with firm skin.

● Meat/Juices: Keep raw meat, poultry, seafood, and their juices away from other foods. In the fridge, place them in a container that can catch any juicy leaks.

● Clean Your Workspace: Wash utensils and surfaces with hot, soapy water before and after they are used to prepare food. Diluted bleach—1 teaspoon of bleach to 1 quart of hot water—can also be used to sanitize utensils and surfaces.

Dietary Recommendations

● Drinking plenty of liquids such as fruit juices, sports drinks, caffeine-free soft drinks, and broths to replace fluids and electrolytes.

● Sipping small amounts of clear liquids or sucking on ice chips if vomiting is still a problem.

● Gradually reintroducing food, starting with bland, easy-to-digest foods such as rice, potatoes, toast or bread, cereal, lean meat, applesauce, and bananas.

● Older adults and adults with weak immune systems should also drink oral rehydration solutions to prevent dehydration.

● Avoiding fatty foods, sugary foods, dairy products, caffeine, and alcohol until recovery is complete.

Infants and children present special concerns, as they are likely to become dehydrated more quickly from diarrhea and vomiting because of their smaller body size. The following steps may help relieve symptoms and prevent dehydration in infants and children:

● ● ● ● Giving oral rehydration solutions to prevent dehydration.

● ● ● ● Giving bland food as soon as the child is hungry.

● ● ● ● Giving infants breast milk or full strength formula, along with oral rehydration solutions.