Food Poisoning

  • Medical Author:
    Benjamin Wedro, MD, FACEP, FAAEM

    Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

Quick GuideUncommon and Common Food-Poisoning Dangers in Pictures

Uncommon and Common Food-Poisoning Dangers in Pictures

What are the signs and symptoms of food poisoning?

Food poisoning most commonly causes:

  • abdominal cramps,
  • vomiting, and
  • diarrhea.

This can cause significant amounts of fluid loss and diarrhea along with nausea and vomiting may make it difficult to replace lost fluid, leading to dehydration. In developing countries where infectious epidemics cause diarrheal illnesses, thousands of people die because of dehydration.

As noted in the section above, other organ systems may be infected and affected by food poisoning. Symptoms will depend upon what organ system is involved (for example, encephalopathy due to brain infection).

Are food poisoning and stomach flu the same thing?

Food poisoning and the stomach flu may or may not be the same thing, depending if the causative agent is transmitted by contaminated food, or if the agent is transmitted by non-food mechanisms such as body secretions. Most health-care professionals equate stomach flu to viral gastroenteritis.

Stomach flu is a non-specific term that describes an illness that usually resolves within 24 hours and is caused commonly by the adenovirus, Norwalk virus or rotavirus, (rotavirus is most commonly found in children).

If numerous cases of "stomach flu" occur in a situation where many people have been eating, it certainly may be considered food poisoning. Norwalk virus is responsible for many cases of food borne illness outbreaks on cruise ships.

How long does food poisoning last?

Most cases of food poisoning last about 1 to 2 days and symptoms resolve on their own. If symptoms persist longer than that, the affected person should contact their health-care professional.

Cyclospora infections may be difficult to detect and diarrhea may last for weeks. health-care professionals may consider this parasite as the potential cause of food poisoning in patients with prolonged symptoms.

What are the types of food poisoning?

Most frequently, food poisoning may be due to infection caused by bacteria, viruses, parasites, and infrequently, prions. More than 200 infectious causes exist. Sometimes it is not the bacteria that causes the problem, but rather the toxin that bacteria produce in the food before it is eaten. This is the case with Staphylococcal food poisoning and with botulism.

Other illnesses may involve chemical toxins that are produced in certain foods that are poorly cooked or stored. For example, scombroid poisoning occurs due to a large release of histamine chemical from the fish when it is eaten. It causes facial swelling, itching, and difficulty breathing and swallowing - just like an allergic reaction. Scombroid poisoning is sometimes confused with a shellfish allergy.

Some "food poisonings" may not be due to toxins or chemicals in food but to infectious agents that happen to contaminate the food. E. coli O157:H7 (hemorrhagic E. coli) usually occurs when contaminated food is eaten, but it also can spread from contaminated drinking water, a contaminated swimming pool, or passed from child to child in a daycare center.

Listeria is a type of bacteria that has caused the two most deadly outbreaks of food poisoning in United States history. In 1985, an outbreak in California was traced to eating a type of fresh cheese, and in 2011, Listeria food poisoning was traced to a cantaloupe farm and processing operation in Colorado. It is most often associated with eating soft cheeses, raw milk, contaminated fruits, vegetables, poultry, and meats. Newborns, the elderly and others with compromised immune systems are at higher risk of becoming ill with Listeria infections. Pregnant women are also at higher risk of contracting Listeria infections and are recommended to avoid soft cheeses like brie, camembert, and blue (cream cheese is safe) to avoid infection and to prevent transmission to the fetus.

Medically Reviewed by a Doctor on 11/4/2016

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