FOOD POISONING: Symptoms, Causes & Risk Factors


Here are the symptoms, causes, and risk factors of food poisoning

FOOD POISONING – This condition is also called foodborne illness that happens when you eat contaminated food. Bacteria, viruses, and parasites that are known to be infectious organisms and they are the common cause of food poisoning.

food poisoning causes symptoms risk factors
Photo courtesy of NY Times


  • Nausea
  • Vomiting
  • Watery or bloody diarrhea
  • Abdominal pain and cramps
  • Fever

The symptoms may vary depending on the source of contamination and these may manifest an hour after eating the contaminated food. However, there are instances that the symptoms will begin to manifest days or weeks later. The sickness from this condition may last for a few hours or several days, according to an article from Mayo Clinic.


Food can be contaminated at any point of production. It can happen during growing, harvesting, processing, storing, shipping or preparing. Aside from this, there is also cross-contamination. This happens when the harmful organisms transfer from a surface to another, which is a common cause of this condition.

Heres the table showing the possible contaminants, when a person will start to feel the symptoms and the common ways the organism is spread.

ContaminantOnset of symptomsFoods affected and means of transmission
Campylobacter2 to 5 daysMeat and poultry. Contamination occurs during processing if animal feces contact meat surfaces. Other sources include unpasteurized milk and contaminated water.
Clostridium botulinum12 to 72 hoursHome-canned foods with low acidity, improperly canned commercial foods, smoked or salted fish, potatoes baked in aluminum foil, and other foods kept at warm temperatures for too long.
Clostridium perfringens8 to 16 hoursMeats, stews and gravies. Commonly spread when serving dishes don’t keep food hot enough or food is chilled too slowly.
Escherichia coli (E. coli) O157:H71 to 8 daysBeef contaminated with feces during slaughter. Spread mainly by undercooked ground beef. Other sources include unpasteurized milk and apple cider, alfalfa sprouts, and contaminated water.
Giardia lamblia1 to 2 weeksRaw, ready-to-eat produce and contaminated water. Can be spread by an infected food handler.
Hepatitis A28 daysRaw, ready-to-eat produce and shellfish from contaminated water. Can be spread by an infected food handler.
Listeria9 to 48 hoursHot dogs, luncheon meats, unpasteurized milk and cheeses, and unwashed raw produce. Can be spread through contaminated soil and water.
Noroviruses (Norwalk-like viruses)12 to 48 hoursRaw, ready-to-eat produce and shellfish from contaminated water. Can be spread by an infected food handler.
Rotavirus1 to 3 daysRaw, ready-to-eat produce. Can be spread by an infected food handler.
Salmonella1 to 3 daysRaw or contaminated meat, poultry, milk, or egg yolks. Survives inadequate cooking. Can be spread by knives, cutting surfaces or an infected food handler.
Shigella24 to 48 hoursSeafood and raw, ready-to-eat produce. Can be spread by an infected food handler.
Staphylococcus aureus1 to 6 hoursMeats and prepared salads, cream sauces, and cream-filled pastries. Can be spread by hand contact, coughing and sneezing.
Vibrio vulnificus1 to 7 daysRaw oysters and raw or undercooked mussels, clams, and whole scallops. Can be spread through contaminated seawater.


Older adults are more prone to food poisoning as the immune system of humans also weakens as they get older. This is the same thing that happens to infants and young children as their immune system is not yet fully developed. The risk is also higher for pregnant women as, during pregnancy, changes in metabolism and circulation increases their vulnerability to the condition. Those who have chronic diseases, such as diabetes, liver disease or AIDS or those who are undergoing chemotherapy or radiation therapy for cancer are more prone to this because of the reduced response of their immune system, according to the article.

READ ALSO: SEASONAL ALLERGY: Food That Might Alleviate This Condition


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