Food poisoning

Last updated: November 13, 2023

Summarytoggle arrow icon

Food poisoning is a specific subset of foodborne illnesses and is caused by the ingestion of any substance that is contaminated with a preformed toxin. Symptoms usually occur within hours of ingesting contaminated food and resolve over the course of 1–2 days. Common clinical features include nausea, vomiting, diarrhea, and abdominal cramping. Diagnostic testing is usually not required unless the symptoms are severe, prolonged, or systemic, e.g., high fever or severe dehydration. Most cases of food poisoning are self-limited and require only supportive care (e.g., oral and/or parenteral rehydration and antiemetics) to ensure adequate hydration. Young children, immunocompromised individuals, and older adults are at greater risk for developing complications related to food poisoning and may require close monitoring. Seafood poisoning may involve more dangerous toxins and additional treatment from antihistamines to cardiopulmonary resuscitation may be required.

For a general overview of all foodborne illnesses, see “Overview of foodborne illnesses,” for an overview of all infectious gastroenteritis types, see “Infectious gastroenteritis.”

Definitiontoggle arrow icon

Clostridium botulinum is a rare and potentially fatal cause of food poisoning. See botulism for details.

Overview of foodborne diseasestoggle arrow icon

Foodborne illness refers to any disease following ingestion of contaminated food. Contaminants include infectious (e.g., bacteria, viruses) and noninfectious agents (e.g., pesticides, food additives, allergens, mushroom poisoning, metal toxicity). An overview of infectious foodborne illnesses classified according to the predominating symptoms is provided here. For details on bacterial pathogens, see the article on bacterial gastroenteritis. [1][2][3][5]

Predominantly vomiting

Pathophysiology: Vomiting is commonly due to delayed gastric emptying caused by changes to gastric motility.

Overview of pathogens predominantly causing vomiting
Pathogen Foods/transmission Incubation period Treatment

Staphylococcus aureus

  • Canned meats, mayonnaise/potato salad, custards
  • 1–8 hours
  • Supportive
Bacillus cereus
  • Reheated rice, food kept warm but not hot
  • Supportive

Noroviruses (e.g., Norwalk virus) [6]

  • Fecal-oral
  • 12–48 hours
  • Supportive

Symptom onset and resolution are quick in S. aureus and B. cereus poisoning: S. aureus and B. cereus are fast and fureus.

Predominantly diarrhea

Watery diarrhea [7]

Overview of pathogens predominantly causing watery diarrhea
Pathogen Foods/transmission Incubation period Treatment
Staphylococcus aureus
  • Inadequately refrigerated food
  • 1–8 hours
  • Supportive

Clostridium perfringens [8][9]

(Heat-labile enterotoxins cause the symptoms.)

  • Germination of spores in heavily contaminated food that is left standing at < 60°C for too long → vegetative bacteria
  • The foods most likely to have been colonized include:
    • Reheated meat dishes
    • Undercooked meat and raw legumes
  • 6–24 hours
  • Supportive; usually resolves in 24 hours
  • Antibiotics are not recommended.

Enterotoxic Escherichia coli (ETEC) [10]

(Heat-labile toxin induces diarrhea; most common cause of traveler's diarrhea)

  • Recent travel (e.g., Asia, Africa, the Middle East, Mexico, Central, or South America)
  • Undercooked meat, endogenous
  • Fecal-oral
  • 9 h to 3 days
Listeria monocytogenes
  • Soft cheese, deli meats, unpasteurized milk, coleslaw, hot dogs,
  • 1–2 days
Vibrio cholerae
  • 0–2 days

Enteric viruses (adenovirus, norovirus, rotavirus)

  • Fecal-oral

Cryptosporidium [11]

  • Fecal-oral (oocysts are excreted in stool and contaminate drinking water)
  • 5–7 days
Cyclospora (Cryptosporidium cyclospora cayetanensis) [12][13]
  • Fecal-oral
  • 5–7 days
Intestinal tapeworms
  • Larvae in undercooked pork/beef, raw freshwater fish
  • 6–8 weeks
  • Asymptomatic for years

Invasive diarrhea [14][15][16]

Overview of pathogens predominantly causing invasive diarrhea
Pathogen Foods/transmission Incubation period Treatment
Salmonella typhi or paratyphi
  • Poultry/eggs, meat
  • Most commonly 7–14 days
  • 4–6 days

Inflammatory diarrhea [14][15][17]

Overview of pathogens predominantly causing inflammatory diarrhea
Pathogen Association Foods/transmission Incubation period Treatment
Salmonella (hundreds of strains, including S. enteritidis and S. typhimurium)
  • Poultry/eggs
  • Chicken products: eggs, raw chicken
  • 6–48 hours
Campylobacter jejuni
  • Poultry
  • Fecal-oral
  • Days
Shigella dysenteriae
  • Second most common association with hemolytic-uremic syndrome (HUS)
  • Fecal-oral
  • Days
Yersinia enterocolitica
  • More common in children and during the winter season
  • Contaminated milk, pork
  • Days
Vibrio (usually parahaemolyticus) [18][19]
  • Shellfish
  • Raw/undercooked seafood
  • 16–72 hours

Enterohemorrhagic Escherichia coli (EHEC) [10]

  • Undercooked meat
  • Untreated water; contaminated food, such as unpasteurized dairy products (milk, soft cheese) or apple cider
  • Fecal-oral
  • 3–4 days
  • Supportive
  • Antibiotics are contraindicated because they increase the risk of HUS.

Additional nongastrointestinal symptoms

Pathogens Predominating symptoms Foods/Transmission Incubation period Treatment
Clostridium botulinum
  • Descending paralysis
Histamine fish poisoning
  • Inadequately refrigerated fish
  • 5 minutes to 1 hour
Brucellosis (Brucella spp.) [20]
  • Unpasteurized dairy products
  • Contact with animals (e.g., hunter)
  • 2–4 weeks (range: 5 days to 5 months)
Hepatitis A (Hepatitis A virus) [21]
  • Jaundice, commonly following initial GI symptoms
  • Fecal-oral
  • 28 days (range 14–50 days)

Vibrio vulnificus [22][23]

  • Oysters, undercooked seafood
  • Contact with contaminated water or shellfish (wound infections)
  • 1–7 days
Salmonella typhi and paratyphi
  • Fecal-oral
  • Hours
  • Reef fish containing Gambierdiscus toxicus
  • 6–24 hours
  • Supportive

Common sources of fecal-oral transmission in intestinal diseases are the 5 F's: fingers, feces, food, fluids, flies.

Management of food poisoningtoggle arrow icon

Staphylococcal food poisoningtoggle arrow icon

Staphylococcal food poisoning is one of the most common confirmed source of foodborne illness. [24][25]

Clostridium perfringens food poisoningtoggle arrow icon

Clostridium perfringens is the second most common cause of foodborne illness in the United States. [1][26]

Bacillus cereus infectiontoggle arrow icon

Bacillus cereus can produce two different enterotoxins which cause two distinct food poisoning syndromes. [1][7]

  • Pathogen: Bacillus cereus, a heat-stable, spore-forming gram-positive rod
  • Transmission: ingestion of bacteria growing in heated food that is improperly refrigerated
  • Emetic form [28]
    • A heat-stable toxin (cereulide) is produced by bacteria in food and survives cooking.
    • Commonly associated with reheated rice: Spores survive the cooking process, germinate in warm rice, and produce more enterotoxin.
    • Onset after ingestion: 1–3 hours
    • Duration: 6–24 hours
    • Clinical features: Nausea and vomiting predominate.
  • Diarrheal form
    • A thermolabile toxin is produced by organisms during the growth phase in the intestine.
    • Associated with a broad range of food, e.g., meat, vegetables, milk products
    • Onset after ingestion: 8–16 hours
    • Duration: 12–24 hours
    • Clinical features: abdominal pain, diarrhea, nausea
  • Treatment (both forms) [5][15]

Poisoning from reheated rice can be serious (B. cereus).

Seafood poisoningtoggle arrow icon

Histamine fish poisoning (scombroid poisoning) [2][15][29]

Scombroid poisoning is often confused with fish allergy; offer patient education on histamine fish poisoning and/or skin testing after symptoms have resolved. [29]

Individuals taking isoniazid or monoamine oxidase inhibitors are at increased risk for histamine fish poisoning because these drugs impair histamine metabolism. [29]

Reef fish poisoning (ciguatera fish poisoning) [2][15][30]

Recommend avoidance of alcohol and nuts for 3–6 months after poisoning as they may exacerbate residual symptoms. [2]

Puffer fish poisoning [2][34]

No antidote exists for tetrodotoxin, but recovery is likely if the patient survives the first 24 hours. [36]

Preventiontoggle arrow icon

Food and water precautions are the best means for preventing food poisoning. [37][38]

  • Food hygiene
    • Wash hands and disinfect surfaces frequently.
    • Wash fruits and vegetables with safe drinking water.
    • Avoid cross-contamination by keeping raw meat products, eggs, and seafood separated from other kinds of food.
    • Use a food thermometer while cooking.
    • Maintain a refrigerator temperature < 4°C (40°F).
    • When traveling (especially in resource-limited countries): Only consume fully cooked or dry (e.g., bread, crackers) foods, pasteurized dairy products, and fruits and vegetables you can peel or have properly washed yourself.
  • Water hygiene
    • Do not consume untreated water or ice.
    • Options if water treatment is unknown:
      • Consume sealed bottled beverages.
      • Boil water for at least one minute before consuming.
      • Use an appropriate filter.

There is a simple rule to avoid foodborne illness while traveling: Boil it, cook it, peel it, or forget it. [37]

Referencestoggle arrow icon

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