Food poisoning is the ingestion of food contaminated with disease-causing bacteria or viruses. The Centers for Disease Control and Prevention (CDC) estimates 76 million cases of foodborne illness occur annually in the United States. A variety of bacteria and viruses cause food poisoning. The illnesses caused by different forms of food poisoning range in severity from self-limited gastrointestinal upset to life-threatening infections. Proper cooking and food handling and hand washing can significantly reduce the occurrence of food poisoning.
Foodborne Botulism
The bacterium Clostridium botulinum causes foodborne botulism. This rare but potentially life-threatening form of food poisoning is usually contracted from home canned vegetables or fruits contaminated with Clostridium botulinum from the soil. The bacteria produce botulinum toxin, which is absorbed into the bloodstream and travels to the nerves, causing paralysis. Importantly, boiling foods for a minimum of 10 minutes destroys botulinum toxin. Recovery from botulism typically takes three months or more. Early diagnosis and treatment can significantly reduce the effects of the toxin and shorten recovery time.
Shiga Toxin-Producing Escherichia coli
The Escherichia coli (E. coli) bacterial group contains many different species, most of which do not cause disease. A small subgroup of these bacteria produce shiga toxin, which typically causes a diarrheal illness of varying severity. E. coli O157:H7--a shiga toxin producing bacterium--is of particular concern because it can cause a serious complication, hemolytic uremic syndrome. This complication causes breakdown of red blood cells and kidney failure, which may be fatal. The CDC recommends avoiding unpasteurized milk, cheese made from unpasteurized milk, and unpasteurized apple cider because of the high risk of disease-causing E. coli. Any food contaminated with cattle, pork, poultry or lamb feces is a potential source of disease-causing E. coli. Recent outbreaks of E. coli O157:H7 have been linked to alfalfa sprouts, spinach, beef, salami and cookie dough.
Staphylococcal Food Poisoning
Enterotoxin-producing Staphylococcus aureus (S. aureus) is a common cause of food poisoning in the United States. Enterotoxin is a gut-poisoning toxin produced by the bacteria. It produces symptoms within 1 to 6 hours after ingestion of contaminated food. Symptoms include nausea, vomiting, abdominal cramps and watery diarrhea. The illness generally begins to ebb in approximately 8 hours, resolving in 1 to 3 days. A person who has not washed his hands prior to preparing food is typically the source of food contamination. Foods that involve hand preparation such as sandwiches, tacos and salads are common sources of S. aureus food poisoning.
Norovirus Food Poisoning
While most people think of food poisoning as a bacterial illness, viruses frequently cause outbreaks. Noroviruses are highly contagious viruses that typically spread through food contamination. Noroviruses--formerly known as Norwalk virus and Norwalk-like viruses--attack the lining of the stomach and small intestine causing abdominal cramps, nausea, and typically both vomiting and diarrhea. The stool and vomit of people with the illness are infectious. Lack of hand washing, contamination of food, and inadvertent ingestion of the viruses is the typical means of norovirus spread.
References
- Centers for Disease Control and Prevention: Enteric Diseases
- Centers for Disease Control and Prevention: Botulism
- Centers for Disease Control and Prevention: Escherichia coli O157:H7
- Centers for Disease Control and Prevention: E. coli Outbreak Investigations
- American Family Physician: Foodborne Disease and Shiga Toxin-Producing E. coli
