Foodborne illness

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at February 26, 2016
StartDiseasesFoodborne illness

Foodborne illness, which is commonly called food poisoning, is caused by consuming infectious organisms or food pathogens in contaminated food. These infectious organisms include bacteria, parasites, and viruses, as well as their toxins.


Definition & Facts

Food poisoning is very common, with roughly 1 in 6 Americans getting sick every year and 3,000 deaths each year caused from foodborne illness. People over the age of six are more likely to eat contaminated food than younger people. According to the CDC, this country's most common cause of foodborne illnesses is the Norovirus, as well as the bacteria Salmonella, Campylobacter, and Clostridium perfringens.

Symptoms & Complaints

The source of food contamination determines the types of food poisoning symptoms. Most types of food poisoning include symptoms of nausea, vomiting, abdominal pain, diarrhea, and fever.

Significant fluid loss can occur with food poisoning. It is difficult to replace this lost fluid due to continuous vomiting, so dehydration may be a symptom as well. These signs and symptoms can start at any time within a few hours after contaminated food is consumed or could take weeks to begin. These symptoms may last a few hours, or they could persist for several days.


Food can become contaminated at any point while it is being produced. This includes the processes of growing the food, harvesting it, processing it, preparing, or storing it. Cross-contamination is a common cause of food becoming infected with bacteria. This is the transfer of contaminated organisms from one food to another. The most common instance of this is when raw food touches ready-to-eat foods like produce. As produce is commonly eaten raw, harmful organisms are not destroyed by the heat of cooking prior to eating.

Many bacterial, parasitic, or viral agents can cause food poisoning. Some possible contaminants are Campylobacter, Clostridium botulinum, Clostridium perfringens, E. coli, Giardia lamblia, hepatitis A, Listeria, Noroviruses, Rotavirus, Salmonella, Shigella, Staphylococcus aureus, and Vibrio vulnificus.

Several occurrences can contribute to the presence of these harmful pathogens. Contamination of meat and poultry can occur during the processing period if animal feces comes in contact with meat surfaces. This most commonly occurs in undercooked ground beef. Oftentimes, when foods are canned at home, they are done so improperly and can lead to contamination.

Also, foods that are kept at warm temperatures for too long are prone to grow bacteria. Alternatively, germs are also commonly spread when food is either not kept hot enough, or it is chilled too slowly. Raw produce and other ready-to-eat foods can be infected by a food handler with unclean hands. Hot dogs, lunch meats, and unpasteurized dairy products can be contaminated through soil and water.

Diagnosis & Tests

Food poisoning can be diagnosed by the patient providing a detailed medical history. This should include the duration of sickness, the symptoms, and all foods that have been eaten recently. Doctors will perform a physical examination to look for signs of dehydration. Doctors may also conduct diagnostic tests like a stool culture or blood tests to confirm the diagnosis of food poisoning and attempt to identify the cause.

During a stool culture, doctors send a sample of stool to a lab where it is observed for the infectious organism. If a specific organism is found, the doctor is likely to notify the health department to determine if there has been an outbreak. Sometimes, the exact cause of food poisoning is not able to be determined.

Treatment & Therapy

The severity of symptoms and the source of the contaminated food often determine the treatment for foodborne illness. Most people are able to have food poisoning resolve on its own through time and rest, but others need to take action to lessen their symptoms. Replacing fluids that have been lost during the process of food poisoning is vital. Electrolytes, sodium, calcium, and potassium must be balanced to maintain the proper amounts of fluid in the body.

If diarrhea is a symptom, over the counter anti-diarrheal medicines can supply relief. Without treatment, food poisoning may improve on its own. To help recovery progress, several things can be done at home. Stop eating in order to let your stomach settle. Instead of drinking, suck on ice chips or only take small sips of clear soda or weak tea.

Some people who are affected may need hospitalization, in order to receive IV treatment of salts and fluids for prevention or treatment of dehydration. Antibiotics may also be necessary. Doctors may want to prescribe antibiotics if certain bacteria are found in stool cultures if symptoms are severe. It is important to start treatment as soon as possible.

People with food poisoning will know they are getting rehydrated when their urine becomes clear. Gradually begin eating bland food that is low in fat and easy to digest. This includes bananas, rice, applesauce, and toast (BRAT diet). Avoid dairy, alcohol, caffeine, and fatty foods until fully recovered.

Prevention & Prophylaxis

To help prevent food poisoning, always wash your hands thoroughly. Spend time washing food surfaces and utensils as well. Use hot, soapy water to thoroughly clean cutting boards, hands, knives, and cooking tools. Keep raw foods that need to be cooked separate from foods that are ready to eat.

Prevent contamination by keeping raw meat away from other foods. Always cook foods to the proper temperature and use a food thermometer to ensure it is accurate. Most harmful bacteria will be killed if heated to a certain temperature. Freeze or refrigerate perishable foods as fast as possible, and definitely within 2 hours of preparation. Always defrost food in a safe manner. Food should not be thawed at room temperature, but rather it should be defrosted in the refrigerator.

If you are ever in doubt about a certain food, do not eat it. Discard any food that smells or looks off, or if you are not sure of its origin. Food that has been left at room temperature for too long can contain bacteria that can not be killed off by the heat of cooking.