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Food-borne illnesses, also referred to as food borne diseases, food borne infections and food poisoning, are a common, yet preventable, public health problem across the globe.

Foodborne illnesses are diseases that are usually infectious and toxic in nature and can range from mild to severe health problems and risks.

What is a foodborne illness?

A food-borne illness is any illness or disease contracted from the food spoilage of contaminated food.

During the food processing cycle, many disease causing organisms can infect and contaminate foods. This can occur from failure to cook food thoroughly or infestations from pests such as rodents and cockroaches in food processing facilities.

According to the Centres for Disease Control & Prevention (CDC), these examples of contamination, along with several others, result in 48 million cases of foodborne illnesses reported each year in the US alone.

Types of food-borne illnesses

There are roughly around 250 different food-borne illnesses currently in existence. The majority of these food borne diseases are caused by:

  • Bacteria
  • Viruses
  • Parasites
  • Prions
  • Chemicals


Below is a list of the most common food-borne illnesses caused by bacteria:


The CDC reports that salmonella is estimated to cause one million illnesses in the United States alone each year. Globally, the WHO estimate this figure to be around the tens of millions.

The majority of salmonella infections result in developing diarrhea, fever, and abdominal cramps. These causes usually happen 12 to 72 hours after infection.

The majority of salmonella infections usually last between 4 and 7 days, with most patients recovering without treatment. However, there are some cases where the diarrhea becomes quite severe leading to hospitalisation due to dehydration.


Campylobacteriosis is an infectious disease caused by the bacteria of the genus Campylobacter. It is the main cause of foodborne diarrheal infections, and is the most common bacteria that causes gastroenteritis worldwide.

Most infections result in patients developing diarrhea, cramping, abdominal pain, and a fever within two to five days. The diarrhea can sometimes be bloody and patients can sometimes develop nausea and vomiting as a result of infection.

The infection usually lasts around 1 week. Patients with compromised and weak immune systems can sometimes develop life-threatening infections due to campylobacteriosis spreading to the bloodstream.

Escherichia Coli

Escherichia Coli (E. coli) is a bacterium that is commonly found in the gut of humans. Most strains of E.coli are harmless, however, some strains can cause serious food borne diseases.

Enterotoxigenic E. coli (ETEC)

ETEC can cause profuse watery diarrhea and abdominal cramping. Other symptoms, which are less common, include:

  • Fever
  • Nausea with or without vomiting
  • Chills
  • Loss of appetite
  • Headache
  • Muscle Aches
  • Bloating

The food borne illness usually develops 1-3 days after infection and usually lasts 4 days, with some taking a week or longer to resolve. Symptoms usually only last 3 weeks, with most patients recovering with little to no medical support.

Enterohemorrhagic Escherichia coli (EHEC)

EHEC causes symptoms such as abdominal cramps and diarrhoea, and in some cases progresses to bloody diarrhea. Fever and vomiting may also occur. Symptoms usually occur between 3 and 8 days of contraction with patients typically recovering after 10.

According to the WHO, in a small number of patients (around 10%) EHEC develops into life threatening diseases such as Haemolytic Uraemic Syndrome.


The food borne disease, listeria, is caused by the bacterium Listeria Monocytogenes. This infection can lead to miscarriages and deaths of newborn babies. Although, the number of listeria cases worldwide is quite low, its severe health risks and consequences makes it one of the most serious food borne diseases.

Symptoms usually consist of a fever, fatigue and aches in pregnant women. Other symptoms include headaches, stiff necks, confusion, loss of balance as well as fever and muscle aches.

Vibrio Cholerae

Vibrio Cholerae is responsible for causing cholera. Around 3-5 million cases and over 100,000 deaths occur each year around the world.

The infection is usually mild, but around 5-10% of cholerae cases develop into a severe disease where water diarrhea, vomiting and leg cramps are present. In these cases the rapid loss of body fluids results in dehydration and shock.


To add to the food borne infections transmitted through bacteria, viruses also contribute to certain diseases being spread by food.


Norovirus is a very contagious virus. This foodborne illness causes its patients stomach and intestines to become inflamed resulting in stomach pain, nausea, diarrhea and vomiting.

According to the CDC, norovirus is the most common cause of acute gastroenteritis in the United States. Symptoms for this food-borne disease usually develop between 12 and 48 of infection. However, most people recover within 1 to 3 days.


Some parasites which cause foodborne illnesses can only be transmitted through food, others can also infect a subject through direct contact with animals, as well as by entering the food chain via water or soil and contaminated produce.

Foodborne trematodes

Foodborne trematodes is one of those parasites which can only be transmitted through food. According to the WHO, at least 56 million people globally suffer from one or more foodborne trematodiases.

Foodborne trematodiases are caused by the trematode worms. The most common species which affect humans are:

  • Clonorchis
  • Opisthorchis
  • Fasciola
  • Paragonimus

Infection is spread through the consumption of produce which harbours the parasite larvae and can result in severe liver and lung disease.


Echinococcosis is a parasitic disease caused by the tapeworm of the Echinococcus genus. Infection is spread through consumption of produce harbouring the parasite as well as direct contact with an animal host.

Echinococcosis can affect both the lungs and the liver, depending on where the parasite has nested. If located in the liver symptoms include abdominal pain, nausea and vomiting, whilst infection in the lungs symptoms show as a chronic cough, chest pain and shortness of breath.

The WHO states that treatment of this parasite is often expensive and complicated and may require extensive surgery and/or prolonged drug therapy.


The cryptosporidium parasite is responsible for transmitting the cryptosporidiosis disease (crypto for short) which causes watery diarrhea. Individuals with a weak immune system may experience more severe symptoms and can develop a life threatening illness.


Prions are infectious agents composed of protein. They are a unique food-borne illness as they are associated with specific forms of neurodegenerative disease.

They are also presumed to be the cause of the transmissible spongiform encephalopathies.

Unlike other forms of food borne diseases, prions cannot be eliminated through the traditional methods such as heating.

Mad cow disease

Mad cow disease (bovine spongiform encephalopathy) is a food borne infection commonly found in cattle and causes a spongy degeneration in the brain and spinal cord. The disease is believed to be caused by cattle being fed the remains of other cattle in the form of meat and bone meal.

The human version of mad cow disease is called variant Creutzfeldt-Jakob (vCJD). It is believed to be caused by eating beef products contaminated with nervous system tissue such as brain and spinal cord, from cattle infected with mad cow disease.

vCJD is quite hard to diagnose until it has nearly run its course. In the early stages of infection symptoms of depression and loss of coordination become apparent.

Dementia develops in later stages of the illness. Only in advanced stages of the disease can brain abnormalities be detected by MRI scans.

Fatal cases lead to the deterioration of the brain's nerve cells which usually happens after 13 months of the onset of symptoms.

Chemicals caused by contaminated food

Food contaminated with naturally occurring toxins and environmental pollutions are a major health concern due to their ability to cause food-borne illnesses.

Naturally occurring toxins

There are a whole range of naturally occurring toxins which can lead to becoming infected with a food borne disease.

Naturally occurring toxins in food can range from the toxins found in poisonous mushrooms, to the high levels of mycotoxins such as aflatoxin and ochratoxin found in corn and cereals.

Long term exposure to these toxins can severely affect the immune system, and in some cases, cause cancer, according to the WHO.

Persistent organic pollutants

Persistent organic pollutants (POPs) refer to compounds which accumulate in the environment and the human body.

The most well known examples of POPs are dioxins and polychlorinated biphenyls. These are the chemicals released as a result of industrial processes and waste incineration, and are found worldwide in the environment and infect animal food chains.

Humans are at risk by consuming food products contaminated by POPs. Dioxins are extremely toxic. Dioxins cause reproductive and developmental problems and damages to the immune system. They are also known to interfere with hormones as well as cause cancer.


Food can become contaminated with metals such as lead, calcium and mercury. This happens via pollution of the air, water and soil. These lead to illnesses such as lead and mercury poisoning which can result in neurological and kidney damage.

Of course there are a lot more food borne diseases circulating the world, the ones mentioned above are the most common.

How do you get food poisoning?

The biggest cause of food poisoning (foodborne illness) is consuming contaminated foods and beverages.

What is contaminated food?

Contaminated food refers to items which are infected with harmful diseases. This can range from bacteria such as salmonella to contagious viruses which cause gastroenteritis and harmful prions which cause mad cow disease.

How is food contaminated?

Food contamination happens due to a whole range of contributing factors. It is relatively easy for food to become contaminated. Within the food retailing and hospitality sectors a foodborne illness outbreak can potentially affect a large number of people.

Poor hand hygiene

Arguably one of the biggest causes of food borne illness is poor hand hygiene. Businesses involved in food preparation such as manufacturing, hotels and restaurants must pay special attention to hygiene standards and enforce safe practices.

The human hand is responsible for spreading 88% of infections. Harmful pathogens such as bacteria and viruses present on a person's hand can easily be introduced during food handling.


Pests present a big risk to the food industry. Not only can they cause damage to a business’ reputation, but can also contaminate food throughout the food supply chain.

Rodents and cockroaches are known for spreading harmful bacteria and viruses through their urine, droppings, vomit, and also their feet and bodies. If a pest comes into contact with an item of food then there’s a strong possibility for food borne infections such as salmonella could be transmitted.

Food storage

For foodborne illnesses to develop the microbes which cause them need to multiply into large numbers. For this to happen, microbes need warm, moist conditions. Food left out overnight is often at great risk.

Food preparation

Food preparation areas can be at high risk of food contamination. This can happen through a range of ways, however the main source is cross contamination.

Cross contamination happens by transferring germs from one food to another. This can be done through using the same knife, cutting board, and other utensils on multiple food products without washing properly in between each usage.

Animals and plants

Many germs responsible for creating food borne illnesses (such as E.coli) can be found in the intestines of healthy animals. Although these germs remain in the sections of the animal which are discarded, the edible sections can become contaminated during the food manufacturing process. It only takes a small amount of the animal’s intestinal contents to cause a food borne infection.

Plants such as fruits and vegetables (even organic ones) can also be contaminated. This can be via a range of different factors such as being grown in infested soil, or being washed with water contaminated with feces and excrement.

Who is at risk of food poisoning?

Unlike some diseases, food borne illnesses can affect everyone. Anyone can catch food poisoning, and relatively easily.

Some people are more likely to develop food poisoning than others. Apparently some people are naturally more resistant to food poisoning that others. Factors such as stress can also play a part in a person's resistance to food borne diseases.

Certain groups of people are naturally less resistant to food borne illnesses due to a weaker immune system, these are:

  • The elderly
  • Sick people
  • Babies and young children
  • Pregnant women

Food borne illness symptoms

Although there is a wide range of different foodborne diseases you can catch, they all show relatively the same symptoms.

Foodborne illness can have various symptoms including:

  • Diarrhea
  • Vomiting
  • Nausea
  • Abdominal cramps
  • Fever

The number of these symptoms present and their severity depends on the type of food borne illness.

Treating food poisoning

Whilst food borne infections are fairly common, thankfully treatment can be quite simple. Food poisoning can usually be treated at home on your own, without the need for medical intervention.


When treating a foodborne illness it is important to replenish your fluids by drinking plenty of water. Avoiding dehydration is key to recovery.

You can also treat food poisoning by:

  • Resting as much as possible.
  • Try to eat, if and when you feel up to it. But stick to small, light, non-fatty meals first. Bland carbohydrates such as toast, crackers and rice are a good option.
  • Avoid alcoholic, caffeinated and carbonated drinks as well as spicy and fatty foods. These will make you feel worse.

If you find yourself not recovering after a few days, or if you’re showing severe signs of a food borne illness, get professional medical help.

Preventing foodborne illness

Preventing foodborne illnesses is relatively simple. In order to prevent food contamination from harmful pathogens, always follow food safety guidelines and basic food hygiene practises.

Food safety

Food safety is a scientific discipline that ensures the prevention of foodborne illnesses through the handling, preparation, and storage of food. It includes a number of food hygiene routines that should be adhered to in order to prevent the potentially severe health hazards food borne diseases can cause.

5 Principles to safer food

According to WHO the five key principles to safer food are:

  1. Keep clean
  2. Separate raw and cooked
  3. Cook thoroughly
  4. Keep food at safe temperatures
  5. Use safe water and raw materials

Keep clean

Following proper food hygiene and hand hygiene practices can ensure the spread of foodborne illnesses is kept to a minimum.

The harmful microorganisms which cause food borne illnesses are carried on hands, wiping cloths, and cooking utensils. Even the slightest bit of contact can transfer these organisms to food.

You can prevent food borne illnesses by:

  • Ensuring hands are washed regularly — before and after handling food, during preparation, and after using a washroom.
  • If wearing gloves, remember to dispose of them safely and wear a fresh pair when handling different items of food.
  • Wash, sanitize and disinfect all surfaces and equipment used within the food processing cycle.
  • Protect food supply and preparation areas from pests such as rodents, cockroaches, flies and stored product insects.

Separate raw and cooked

Raw food, and in particular meat, poultry and seafood are riddled with dangerous microorganisms (which are eliminated during the cooking process). These microorganisms can easily be transferred during food preparation, transportation and storage and lead to infection from a variety of different food-borne illnesses.

You can prevent foodborne illnesses by:

  • Separating raw meat, poultry and seafood from other foods during preparation, transportation and storage.
  • Use separate equipment and utensils such as knives, chopping boards and plates whilst handling raw foods.
  • Store raw foods in airtight containers and away from cooked foods, and items such as fruit and vegetables which don’t require cooking before consumption.

Cook thoroughly

The majority of the microorganisms that cause food-borne infections are eliminated through heat. Studies have shown that cooking food to a temperature of 70℃ can help ensure it is safe for consumption by thoroughly eradicating any pathogens on the item. 70℃ is the advised temperature as it can kill off even the highest concentrations of microorganisms within 30 seconds. However, in the UK it is advised by food safety professionals that food is held at 70℃ for 2 minutes to reduce harmful bacteria to a safe level.

However, foods such as large joints of meat require special attention to ensure they are thoroughly cooked.

You can prevent food-borne illnesses by:

  • Ensure all food is cooked through thoroughly, especially meat, poultry and seafood.
  • Use a thermometer to check food has reached 70℃ before serving. For meat and poultry make sure the juices run clear.
  • Reheat cooked food thoroughly before serving.

Keep food at safe temperatures

Improper food storing methods can lead to products becoming infected with foodborne illnesses. The microorganisms responsible for causing these diseases can multiply very quickly in food stored at room temperatures.

Ensuring that food is stored at temperatures below 5℃ and above 60℃ (63℃ in the UK) slows down and stops the growth of these microorganisms. However, it is worth noting that some dangerous microorganisms can still grow below 5℃.

You can prevent foodborne diseases by:

  • Ensuring cooked food is not left at room temperature for more than 2 hours.
  • Promptly refrigerating all cooked and perishable food, preferably below 5℃.
  • Keep cooked food at 60℃ (63℃ in the UK) or above before serving.
  • Quickly cool and store leftovers.
  • Prepare food in smaller amounts to reduce the amount of leftovers.
  • Do not store food for longer than 3 days, even in the refrigerator.
  • Do not thaw frozen food at room temperature, use a refrigerator or another cool location instead.

Use safe water and raw materials

Raw materials, ice, and water can be contaminated with dangerous microorganisms and chemicals. Damaged and mouldy foods are often littered with toxic chemicals as well. The same can also be said for soil.

You can prevent food-borne infections by:

  • Taking care in the selection of raw materials.
  • Washing and peeling fruit and vegetables before using.
  • If growing produce, ensure the soil and water used is free from chemicals.
  • Do not use food beyond expiry date.
  • Opt for foods processed for safety such as pasteurized milk.
  • Avoid using food which is damaged or rotting.
  • Throw away smashed, swollen or oxidized cans.

For more information on food safety, and the regulations surrounding it, visit our food safety regulations page.

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