Food poisoning is defined as any disease of an infections or toxic nature caused by the consumption of food or drink. The term is most often used to describe the illness, usually diarrhea and .or vomiting caused by bacteria, virus or parasites.


Most food poisoning is caused by harmful bugs (pathogens) getting into food. The most common types of food poisoning are:

  • bacterial e.g. Salmonella, Campylobacter, E.coli and Listeria
  • viral e.g. Norovirus, Rotavirus and Hepatitis A
  • Intoxication caused by the toxins produced by some bugs such as Staphylococcus aureus, Bacillus cereus and Clostridium perfringens.

Some of these bugs can also be transferred from person-to-person with or without symptoms, or via contaminated surfaces. The symptoms they cause are the same even if food is not involved.


Symptoms of food poisoning range from mild to very severe. Symptoms usually take between a few hours to a few days to begin and may last for a few days, depending on the type of pathogen.

Symptoms often include one or more of:

  • nausea
  • stomach cramps
  • diarrhoea
  • vomiting
  • fever
  • headaches


Some foods accommodate harmful bugs or toxins more than others.

The bugs or toxins may be present on foods at the time of purchase, get onto food by cross contamination and poor hygiene, or grow to harmful levels as a result of poor temperature control.

Harmful bugs can be:

  • carried on the bodies of people handling food
  • frequently present in the throat, nose, skin, hair and faeces
  • Transferred to food after touching the nose, mouth or hair or smoking without washing hands before handling food. Sneezing or coughing around or near food can also lead to contamination.

Food poisoning can be caused by:

  • not cooking food thoroughly
  • not storing food that needs to be chilled below 5°C
  • someone who is ill or has poor hand hygiene handling the food
  • eating food after a ‘use-by’ date
  • cross contamination, where bacteria is spread between food, surfaces, utensils and equipment

Higher risk foods include:

  • meat, especially under cooked mince and rolled, formed or tenderized meats
  • raw or under cooked poultry such as chicken, duck and turkey
  • raw or lightly cooked eggs including foods made from raw egg such as unpasteurized mayonnaise
  • small goods such as salami and hams
  • seafood
  • cooked rice not kept at correct temperatures
  • cooked pasta not kept at correct temperatures
  • prepared salads such as coleslaw, pasta salads and rice salads
  • prepared fruit salads
  • unpasteurized dairy products

Prevention from Food Poisoning

Keeping food safe can be quick and easy. Food safety is vitally important to maintaining good health.

The following key tips are the golden rules for keeping food safe.

Keep it cold

  • keep the fridge below 5oC
  • put any food that needs to be kept cold in the fridge straight away
  • don’t eat food that’s meant to be in the fridge if it’s been left out for 2 hours or more
  • defrost and marinate foods in the fridge, especially meats
  • shop with a cooler bag

Keep it clean

  • wash and dry hands thoroughly before starting to prepare or eat any food, even a snack
  • keep benches, kitchen equipment and tableware clean and dry
  • don’t let raw meat juices drip onto other foods
  • separate raw and cooked food and use different cutting boards and knives for both
  • avoid making food for others if sick with something like diarrhoea

Keep it hot

  • cook foods to at least 60oC, hotter for specific foods
  • reheat foods to at least 60oC, until they’re steaming hot
  • make sure there’s no pink left in cooked meats such as mince or sausages
  • look for clear juices before serving chicken
  • heat to boiling all marinades containing raw meat juices before serving

Check the label

  • don’t eat food past a ‘use-by’ date
  • note a ‘best before’ date
  • follow storage and cooking instructions
  • be allergy aware
  • ask for information about unpackaged foods

The Top 14 Food-borne Pathogens chart as per USFDA  with detailed information about the most common food-borne pathogens.

Pathogen Basics Sources Symptoms
Campylobacter jejuni A bacterium that’s the most common bacterial cause of diarrhea in the U.S. Must-Know: Children under age 1 have the highest rate of Campylobacter infections. Unborn babies and infants are more susceptible on first exposure to this bacterium. In addition, there’s a low threshold for seeking medical care for infants. Raw milk, untreated water, raw and undercooked meat, poultry, or shellfish Diarrhea (sometimes bloody), stomach cramps, fever, muscle pain, headache, and nausea.
Clostridium botulinum A bacterium that can be found in moist, low-acid food. It produces a toxin that causes botulism, a disease that causes muscle paralysis. Must-Know: Don’t feed a baby honey – at least for the first year. Honey can contain Clostridium botulinum spores. Infant botulism is caused by consuming these spores, which then grow in the intestines and release toxin. Home-canned and prepared foods, vacuum-packed and tightly wrapped food, meat products, seafood, and herbal cooking oils Dry mouth, double vision followed by nausea, vomiting, and diarrhea. Later, constipation, weakness, muscle paralysis, and breathing problems may develop. Botulism can be fatal. It’s important to get immediate medical help.
Clostridium perfringens A bacterium that produces heat-stable spores, which can grow in foods that are undercooked or left out at room temperature. Meat and meat products Abdominal pain, diarrhea, and sometimes nausea and vomiting
Pathogenic Escherichia
coli (E. coli)
A group of bacteria that can produce a variety of deadly toxins Meat (undercooked or raw hamburger), uncooked produce, raw milk, unpasteurized juice, and contaminated water Severe stomach cramps, bloody diarrhea, and nausea. It can also manifest as non-bloody diarrhea or be symptomless. Must-Know: E.coli0157:H7 can cause permanent kidney damage which can lead to death in young children.
Listeria monocytogenes A bacterium that can grow slowly at refrigerator temperatures. Must-Know: Listeria can cause serious illness or death in pregnant women, fetuses, and newborns. Refrigerated, ready-to-eat foods (meat, poultry, seafood, and dairy – unpasteurized milk and milk products or foods made with unpasteurized milk) Fever, headache, fatigue, Muscle aches, nausea, vomiting, diarrhea, meningitis, and miscarriages.
Norovirus (Norwalk-like Virus) A virus that’s becoming a health threat. It may account for a large percent of non-bacterial foodborne illnesses. Raw oysters, shellfish, cole slaw, salads, baked goods, frosting, contaminated water, and ice. It can also spread via person-to-person. Diarrhea, nausea, vomiting, stomach cramps, headache, and fever.
Salmonella Enteritidis A bacterium that can infect the ovaries of healthy-appearing hens and internally infect eggs before the eggs are laid. Raw and undercooked eggs, raw meat, poultry, seafood, raw milk, dairy products, and produce Diarrhea, fever, vomiting, headache, nausea, and stomach cramps Must-Know: Symptoms can be more severe in people in at-risk groups, such as pregnant women.
Salmonella Typhimurium Some strains of this bacterium, such as DT104, are resistant to several antibiotics. Raw meat, poultry, seafood, raw milk, dairy products, and produce Diarrhea, fever, vomiting, headache, nausea, and stomach cramps Must-Know: Symptoms can be more severe in people in the at-risk groups, such as pregnant women.
Shigella A bacterium that’s easily passed from person-to-person via food, as a result of poor hygiene, especially poor hand washing. Only humans carry this bacterium. Salads, milk and dairy products, raw oysters, ground beef, poultry, and unclean water Diarrhea, fever, stomach cramps, vomiting, and bloody stools
Staphylococcus aureus This bacterium is carried on the skin and in the nasal passages of humans. It’s transferred to food by a person, as a result of poor hygiene, especially poor hand washing. When it grows in food, it makes a toxin that causes illness. Dairy products, salads, cream-filled pastries and other desserts, high-protein foods (cooked ham, raw meat and poultry), and humans (skin, infected cuts, pimples, noses, and throats) Nausea, stomach cramps, vomiting, and diarrhea
Vibrio cholerae A bacterium that occurs naturally in estuarine environments (where fresh water from rivers mix with salt water from oceans). It causes cholera, a disease that can cause death if untreated. Raw and undercooked seafood or other contaminated food and water. Often absent or mild. Some people develop severe diarrhea, vomiting, and leg cramps. Loss of body fluids can lead to dehydration and shock. Without treatment, death can occur within hours.
Vibrio parahaemolyticus A bacterium that lives in saltwater and causes gastrointestinal illness in people. Raw or undercooked fish and shellfish Diarrhea, stomach cramps, nausea, vomiting, headache, fever, and chills
Vibrio vulnificus A bacterium that lives in warm seawater. It can cause infection in people who eat contaminated seafood or have an open wound exposed to seawater. Raw fish and shellfish, especially raw oysters Diarrhea, stomach pain, nausea, vomiting, fever, and sudden chills. Some victims develop sores on their legs that resemble blisters.
Yersinia enterocolitica A bacterium that causes yersiniosis, a disease characterized by diarrhea and/or vomiting Raw meat and seafood, dairy products, produce, and untreated water  

Fever, diarrhea, vomiting, and stomach pain

Must-Know: Symptoms may be severe for children


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