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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

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.

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Medical Editor:

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.

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Food poisoning facts

• Food poisoning is a common infection that affects millions of people in the United States each year.
• Most commonly, patients complain of vomiting, diarrhea, and crampy abdominal pain.
• People should seek medical care if they have an associated fever, blood in their stool, signs and symptoms of dehydration, or if their symptoms do not resolve after a couple of days.
• Treatment focuses on keeping the patient well hydrated.
• Most cases of food poisoning resolve on their own.
• Prevention is key and depends upon keeping food preparation areas clean, good hand washing, and cooking foods thoroughly.

What is food poisoning?

Food poisoning might be described as a food borne disease. Food that contains a toxin, chemical or infectious agent (like a bacterium, virus, parasite, or prion) and cause symptoms in the body are considered types of food poisoning by most investigators. Those symptoms may be related only to the gastrointestinal tract causing vomiting or diarrhea or may involve other organs such as the kidney, brain or muscle.

Typically most food borne diseases cause vomiting and diarrhea that tend to be short lived and resolve on their own, but dehydration and electrolyte abnormalities may develop. According to the Center for Disease Control and Prevention, 76 million people become ill from food related diseases each year resulting in 325,000 hospitalizations and 5,000 deaths.

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 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 child to child in a day care center. The goal of information included is to introduce the major causes of food poisoning and is not meant to be all inclusive.

Listeria is a 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.