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Knowledge Base » Food Hygiene » Food Poisoning Symptoms and Treatments

Food Poisoning Symptoms and Treatments

Last updated on 20th December 2023

Each year, around one million people in the UK are affected by food poisoning. On a global scale, 1 in 10 people are likely to contract food poisoning at some point in the year, and it is responsible for 33 million deaths. However, whilst it is not the most pleasant of experiences, most cases of food poisoning are not usually severe and the vast majority can be treated at home without the need for further medical attention. The experience depends on the individual, the type of food poisoning, and how much of the contaminated food is consumed, but most people who contract food poisoning will recover within just a few days. However, in the most severe cases, it can result in long-lasting illnesses and even death. Read on to find out more about food poisoning, what causes it, what you can do to avoid it and what to do if you have it.

What is food poisoning?

Food poisoning is an umbrella term that refers to different types of food and water-borne bacteria, viruses and parasites. Although we may see them as being different, food poisoning and stomach bugs are essentially the same things. Both are a result of a viral or bacterial infection which has resulted in inflammation in the lining of the guts, known as gastroenteritis. This is what causes the tell-tale symptoms of vomiting, nausea, diarrhoea and loss of appetite.

The World Health Organisation (WHO) defines food poisoning as:

‘Diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food and water’.

There are hundreds of different viral and bacterial strains that could cause food poisoning, but the main culprits are salmonella, norovirus and campylobacter.

Did you know? In some cases, it is possible to ‘catch’ food poisoning from an infected person.

Although most types of food poisoning are not contagious there are some which can spread through physical contact, touching a contaminated surface or by the person preparing food for someone else. So, if you are sick, it is important to wash your hands frequently to prevent the spread. This is particularly essential if you have diarrhoea, as trace amounts of faecal matter infected with the bacteria can result in further spread.

Woman suffering with food poisoning symptoms

What causes food poisoning?

There are hundreds of different types of food poisoning, with the main categories being:

Viral – Viruses such as norovirus and rotavirus are not living organisms. They are only active when they are residing in a host cell, which they require to reproduce.

Bacterial – Unlike viruses, bacteria are living organisms that respond to the use of antibiotics. Examples of these include salmonella, E. coli and campylobacter.

Parasites – In the UK, food poisoning cases due to parasites are rare but if left untreated, symptoms can be serious and could last months. Many different parasitic infections can cause food poisoning including giardiasis, cryptosporidiosis and amoebiasis, and symptoms usually develop within ten days but it can be weeks after the contaminated food has been consumed.

Moulds, toxins and contaminants – The vast majority of cases of food poisoning in the UK are viral or bacterial, but a person could also be sick if there are moulds, toxins or any other form of contaminant within the food.

As we said, food poisoning is a rather broad term, and food can become contaminated in several different ways.

These include –

  • Not cooking food thoroughly and to the correct temperature
  • Eating food passed its expiry date
  • Eating food that had not been properly stored, such as chilled items that have been left out of the refrigerator
  • Contamination during preparation or cooking
  • Coming into contact with a person who is ill
  • Cross-contamination due to unclean surfaces and equipment.
Pan with oil in it being heated up to ensure contaminated food can be prevented

What are the most common types of food poisoning?

There are so many different types of food poisoning and each has its own symptoms and typical pattern of infection.

The main types include –


Campylobacter bacteria are the most common cause of food poisoning in the UK. Around the world, it is classed as 1 of 4 key global causes of diarrhoeal disease. Symptoms include diarrhoea, which may have some blood in it, stomach cramps and fever, and the onset is usually around 2 to 5 days after exposure; with the illness typically lasting less than a week. This type of bacteria is a contaminant found in raw (unpasteurised) milk, undercooked poultry, and in contaminated water.  For the majority of people, there is no medical treatment necessary, but this can be serious for elderly people, people with a weakened immune system and babies and infants.


Possibly the most well-known form of food poisoning, salmonella is responsible for the highest number of food poisoning-related hospital admissions in the UK. There are more than 2, 000 different strains of this bacterial disease and it is most commonly associated with the contamination of poultry and eggs. However, it can be found on an array of other sources including other types of meat, unpasteurised milk, pressed juice, and raw fruits and vegetables. Symptoms of salmonella can occur anywhere between 6 hours and up to 5 days after the contaminated food has been consumed and they can range from mild stomach pains to severe diarrhoea that could be potentially life-threatening.


Escherichia coli is better known as E.coli and it is a bacteria found in the digestive systems of many animals. Symptoms usually occur between one to eight days after the contaminated food or drink has been consumed, and it is commonly transmitted due to the person eating undercooked beef or drinking unpasteurised milk. In very severe cases, some individuals may go on to develop haemolytic uremic syndrome, which can result in kidney failure and be potentially fatal.


Also known as the stomach flu, norovirus is responsible for quite a bit of sickness in this country. Symptoms of being infected with this virus include diarrhoea, nausea, and vomiting. It is highly contagious but it is not lethal, and the person usually feels better within 1-2 days. High-risk foods include leafy greens, fresh fruit, shellfish and water, and it can also be spread from person to person or by touching contaminated surfaces. If someone in your home has contracted norovirus, it is important to ensure strict hygiene, including disinfecting surfaces, doorknobs and the bathroom after the person has used it.

Staphylococcus aureus

Also known as Staph, this is a common type of bacteria that has a fast onset, with symptoms occurring around 30 minutes to 6 hours after food has been consumed. These usually include nausea, vomiting, diarrhoea, and stomach cramps amongst others. Staph is often transmitted via foods that are not cooked after they have been handled, such as cooked meats, pastries and sandwiches.

Clostridium Perfringens

This is usually a short term form of food poisoning with symptoms often lasting for less than 12 hours and occurring around 6-24 hours after consumption. It is particularly common in undercooked beef and poultry.

Food Poisoning Symptoms

With more than 250 types of food poisoning, there are also lots of different potential symptoms and they can each affect us in different ways. The experience of food poisoning can also vary between individuals, depending on how much the person has consumed and how sensitive they are. Symptoms generally occur within one or two days of eating food that has been contaminated but can occur anywhere within a few hours or up to a few weeks later. If you continue to feel sick after some time, are unable to keep down fluids or just have any concerns, it is advised that you seek medical advice.

Some symptoms are common, these include –

  • Nausea
  • Vomiting
  • Abdominal pain
  • Diarrhoea
  • Lack of appetite.

Other symptoms may include –

  • Bloating and Gas
  • Fever
  • Muscle Aches
  • Weakness and Fatigue
  • Headaches.

When should I seek medical advice for food poisoning?

For most people, food positioning is an unpleasant experience but it will pass, and there is no specific form of treatment. However, in some cases, it can be serious, particularly for those who are at high risk. For example, elderly people, those who are pregnant, people who Crohn’s disease, people with a weak immune system and babies and infants.

If you are concerned or worried, seek medical advice, especially if you experience the following –

  • Diarrhoea which has continued for more than seven days
  • Vomiting that has lasted for longer than two days
  • Blood in your faeces
  • Symptoms of dehydration, such as headaches, feeling light-headed, and dizziness
  • Inability to keep fluids down
  • High temperature.
Man suffering food poisoning symptoms

What foods are particularly susceptible to contamination?

Due to the risk of cross-contamination, any type of food can cause food poisoning if not handled properly and hygiene standards are not maintained. However, certain foods are particularly high risk:


Proteins such as fish, meat and eggs re probably the most high-risk food, with undercooked poultry such as chicken being one of the key causes of food poisoning. Campylobacter and salmonella are two common contaminants on undercooked chicken, and these can result in a serious case of food poisoning. This is why you must always cook poultry thoroughly and ensure that it is evenly cooked throughout.


Eggs and egg-related products can also cause food poisoning, especially when they are consumed raw or undercooked. However, in the UK, significant safety controls are surrounding this, so just look for the British lion stamp for peace of mind.

Red Meats

Several types of food poisoning can be obtained from consuming red meats, including beef, lamb and pork. The majority of food poisoning causes are destroyed by cooking thoroughly. However, whole cuts of beef or lamb and cuts like steaks can be served rare as there is not likely to be bacteria on the inside of the product. However, foods such as burgers and sausages should always be cooked through and to the appropriate temperature. Whilst pink burgers may be a possibility in some restaurants, there are very strict controls and tests that they have to go through to allow this and it is not something that you should try at home.

Fish and Shellfish

Fish can be dangerous if it is not stored and cooked properly, due to a risk of the fish becoming contaminated. Fish should always be kept chilled or frozen, as fish that has been left at room temperature can be dangerous.

Shellfish can also contain a number of contaminants, and you should always ensure that they are cooked until they are open. Discard any that are not open after the cooking process.


Rice can contain a type of bacteria called Bacillus cereus, otherwise known as B. cereus. When left at room temperature, this bacterium multiplies and produces a toxin that results in food poisoning. You shouldn’t leave rice to stand for long periods; serve it as soon as it is cooked and ensure that you refrigerate any leftovers as soon as possible.

Cooked Meats

All meat carries a risk of food poisoning, but this is often reduced by ensuring that the product is cooked properly. However, cooked meats such as ham, deli meats and hotdogs can be contaminated during the processing stage, with potential bugs including Listeria and Staphylococcus.

Dairy products

The vast majority of dairy products are fine, but if the milk is unpasteurised, there are some risks. In parts of the UK, it is legal to sell raw milk products but the vendor has a responsibility to ensure that customers are aware of the potential risks. However, the policy surrounding this does vary across the devolved nations.

Raw Honey

Raw honey can harbour Clostridium botulinum, an especially harmful bacteria to babies, infants and pregnant people. This can lead to botulism poisoning that could potentially result in life-threatening paralysis.

Fresh fruit and Vegetables

Any fresh fruit or vegetable could pick up a bug during the growing, processing and sales process. This is why it is important to always wash any fruit or veg that you plan to eat raw. Melon and berries are particularly high risk, and it is important to make sure that as well as washing thoroughly, you store freshly cut fruit in the refrigerator right away. Salad leaves can also be susceptible to causing food poisoning, and should always be washed. Plus, if there are any soggy or ‘gone off’ leaves in a mixed salad bag, it is best to discard all of them.

What should I eat when I have food poisoning?

One of the most common symptoms of food poisoning is a lack of appetite, and you may not feel like eating for a day or two. However, when you do start eating again, it is advised that you eat little amounts often. It is also recommended bland high-carb foods that will be gentle on your stomach, such as bread, pasta and cracks. Ease into eating, and avoid anything spicy or greasy. You are also recommending staying away from carbonated drinks, caffeinated beverages such as tea and coffee, alcohol and nicotine.

Loaf of bread being cut, which should be eaten if you have had food poisoning

Do I need to report food poisoning in the UK?

In the UK, our food supply is one of the safest in the world, and we have extensive legislation in place to prevent the risk. Furthermore, whilst it is easy to assume that food poisoning has been obtained from food eaten right before a person got sick; this is not always the case. There are so many different types and each of these have varied incubation periods. However, if you think that you have contracted food poisoning from a product you have purchased or a meal you have eaten, it should be reported to your local environmental health department. They will then investigate to see whether the premises where you purchased the food are practising the rules set out in the Food Safety Act 1990. You can also report concerns online at the Food Standards Agency, and this is also a great place to check out a premises hygiene rating before you eat.

How can I avoid getting food poisoning?

The best way to avoid food poisoning is by ensuring that you practice the Food Standard Agency’s Four Cs of cleaning, cooking, chilling and (avoiding) cross-contamination

Cross Contamination

This refers to situations in which contaminants are transferred from one surface to another, and this could include between food types, surfaces, equipment or hands. Food can become contaminated at any point during the process; from production to storage and from cooking to consumption. When you are preparing food, it is important to wash your hands frequently, and that you wash utensils and cooking equipment in between uses. Restaurants use different coloured chopping boards as a way of reducing the risk of contamination, and this is something that you can adopt at home. The correct use is red for raw meat, blue for raw fish, yellow for cooked meats, green for salads and fruits, brown for vegetables and white for dairy products.


Effective cleaning will ensure that your utensils and equipment are free from harmful bacteria and viruses. Disinfect work surfaces, use cleaning products that are suitable for the job such as anti-bacterial sprays, and do not let food waste build. It is usually best to clean as you go but it is also advised that you do a regular deep clean as well.


This refers to the importance of proper storage, especially for foods that need to be kept at a certain temperature. If you are storing leftovers, make sure that they are put in the refrigerator within four hours being cooked. It is also advised that you label them with the date to give you an idea of whether they are edible.

For the best way to store your food, it is best to check the label carefully. You should also pay attention to the use-by date. A use-by date is a safety warning used on foods that can go off quickly and can be dangerous after a certain period. This is not to be confused with a best before date which refers to the quality of the product.


Cooking food properly is the most effective way of removing mostly harmful contaminants. Follow the label instructions to ensure that you cook your food for long enough and at the right temperature; ensuring that you pre-heat the oven when required. Making sure that food is piping hot throughout can be more difficult in the microwave, and you should stir food at various intervals. Investing in a meat thermometer is a great way to ensure that meat is cooked thoroughly and to the appropriate temperature; just make sure that it is cleaned after each use.

With an estimation that 85% of food poisoning cases could have been avoided with proper care and handling, maintaining hygiene and ensuring that appropriate system in place is the most effective way of avoiding it. This means that the best way of beating food poisoning is with a defensive strategy; keeping the four Cs in mind throughout.

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About the author

Sarah Wilkinson

Sarah Wilkinson

Sarah graduated in 2012 from Trinity St. David, University of Wales, with a 1st class honours degree in Social Inclusion and Justice. After her studies, she taught English around the world for almost 8 years, spending several years in Turkey and Spain.

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