Food safety

Teacher's reference notes on food safety, food allergies and intolerances.


Keeping yourself and your kitchen clean is essential to keep food safe, otherwise bacteria can grow and spread.


  • Having clean hands is the first step to making safe food. Our hands can carry dirt and bacteria which can spread onto food very easily if we don’t wash our hands properly.
  • Wash your hands thoroughly with soap and warm water
    • before starting to prepare food
    • after touching raw meat or poultry
    • after using the toilet
    • after touching the bin
    • after touching pets
    • after blowing your nose or sneezing.
  • Don't forget to dry your hands thoroughly because if they are wet they will spread bacteria more easily.

Worktops and chopping boards

  • Keep worktops and chopping boards clean by washing thoroughly in between uses with hot, soapy water, particularly after they have been touched by raw meat, including poultry, or raw eggs. If they aren't properly clean, bacteria could spread to food and make you ill.
  • Ideally, it’s better to have separate chopping boards for raw meat and ready-to-eat foods.
  • Wipe up any spilled food straight away.


  • Dirty, damp cloths are the perfect place for bacteria to grow so it's very important to wash kitchen cloths and sponges regularly and leave them to dry before using them again.
  • Tea towels can also spread bacteria so it's important to wash them regularly and be mindful about cross contamination when using them. Remember, if you wipe your hands on a tea towel after you have touched raw meat, this will spread bacteria to the towel. Then, if you use the tea towel to dry a plate, the bacteria will spread to the plate.


  • It's important to keep knives, wooden spoons, spatulas, tongs, etc. clean to help stop bacteria spreading to food.
  • It's especially important to wash them thoroughly after using them with raw meat, because otherwise they could spread bacteria to other food.

Cross contamination

  • Cross contamination is one of the major causes of food poisoning. It is the transfer of bacteria from foods (usually raw) to other foods.
  • Bacteria can be transferred directly when one food touches (or drips on to) another, or indirectly from hands, equipment, work surfaces or knives and other utensils.
  • To prevent cross-contamination and stop bacteria from spreading:
    • Keep raw meat and unwashed vegetables separate from ready-to-eat foods.
    • Don't let raw meat drip onto other food – keep it in sealed containers on the bottom shelf of your fridge.
    • Never use the same chopping board or knife for raw meat and ready-to-eat food, unless the utensils have been washed thoroughly in between.
    • Always wash your hands thoroughly after touching raw meat.
    • Don't wash meat before cooking it. Washing doesn't get rid of harmful bacteria – only proper cooking will. You will run the risk of splashing bacteria that may cause food poisoning onto worktops and utensils.


  • Cooking food properly is essential to make sure it is safe as well as tasty. Cooking kills harmful bacteria in the food.
  • To check food is properly cooked, make sure it’s steaming hot all the way through – this means that it is hot enough to have steam coming out of it when you cut into the middle.
  • Use a food thermometer to ensure food is cooked properly. The core temperature should reach 75°C.
  • It is very important to make sure poultry, pork, burgers and sausages are cooked all the way through. Check that there isn’t any pink meat visible and that the juices don’t have any pink or red in them. It's fine to eat steaks and other whole cuts of beef and lamb rare, as long as the outside has been properly cooked or 'sealed'. It's important to seal meat to kill any bacteria that might be on the outside. You can tell that a piece of meat has been properly sealed because all the outside will have changed colour.
  • When you have cooked food, serve it straight away. Or, if you are cooking food in advance, cool it down as quickly as possible (ideally within one to two hours) and store it in the fridge until you are ready to eat it. Don’t reheat food more than once and when reheating, ensure that food is steaming hot all the way through. If the food is only warm, it might not be safe to eat and in fact the warm temperatures may provide the ideal conditions for bacteria to grow.
  • Eating reheated rice can lead to food poisoning however it's not actually the reheating that's the problem – it's the way the rice has been stored before reheating.
    • Uncooked rice can contain spores of Bacillus cereus, bacteria that can cause food poisoning. When the rice is cooked, the spores can survive. Then, if the rice is left standing at room temperature, the spores will germinate into bacteria. These bacteria will multiply and may produce toxins (poisons) that cause vomiting or diarrhoea. Reheating the rice won't get rid of these toxins.
    • So, the longer cooked rice is left at room temperature, the more likely it is that bacteria, or the toxins they produce, could stop the rice being safe to eat.
    • It's best to serve rice when it has just been cooked. If that isn't possible, cool the rice as quickly as possible (ideally within one hour) and keep it in the fridge for no more than one day until reheating.


  • It is important to keep certain types of food in the fridge to ensure they are safe to eat. Refrigeration slows the growth of bacteria and stops food from spoiling too quickly. Remember to keep your fridge at the right temperature (below 5°C). If your fridge is full, turn the temperature down to help it fight bacteria. You can check your fridge temperature using a fridge thermometer.
  • Keep the fridge door closed as much as possible.
  • Make sure food is cool before you put it in the fridge.
  • If you have any leftover cooked food, cool it as quickly as possible (ideally within one to two hours) and then store it in the fridge.
  • If you have cooked something large, like a turkey or a big pot of stew or curry, split it up into smaller portions. This will help the food cool down more quickly and will make it easier to fit in the fridge.
  • If you're having a party or making a buffet, leave the food in the fridge until people are ready to eat. Generally, you shouldn't leave food out of the fridge for more than four hours.

Barbecue and outdoor eating

  • Defrost meat and poultry before cooking.
  • Keep marinating meat and poultry in the fridge. Don’t re-use the marinade.
  • Use separate utensils for raw and cooked meat. If this is not possible, wash them thoroughly in between uses.
  • Turn food regularly as it cooks on the barbeque to avoid burning on one side and under cooking on the other.
  • Keep food out of the fridge for the shortest time possible.
  • Keep hot foods hot and cold foods cold - don’t leave them standing around.
  • Keep pets away from food, dishes and preparation surfaces.

Use by

  • You will see 'use by' dates on food that goes off quickly, such as smoked fish, meat products and ready-prepared salads. Don't use any fresh food or drink after the 'use by' date on the label, even if it looks and smells fine. This is because using it after this date could put your health at risk.
  • ‘Use by’ does not always mean ‘eat by’. Some foods can be frozen and its life can be extended beyond the ‘use by’ date. But make sure you follow any instructions on the pack – such as 'freeze on day of purchase', 'cook from frozen' or 'defrost thoroughly before use and use within 24 hours'. It is also important you follow any instructions for cooking and preparation shown on the label.
  • Once a food with a 'use by date' on it has been opened, you also need to follow any instructions such as 'eat within a week of opening'. However, if the 'use by' date is tomorrow, then you must use the food by the end of tomorrow, even if you only opened it today.

Best before

You will usually see 'best before' dates on foods that last longer, such as frozen, dried or canned foods. It should be safe to eat food after the 'best before' date, but the food will no longer be at its best. After this date, the food might begin to lose its flavour and texture.


  • Store eggs in a cool, dry place, ideally in the fridge.
  • Store eggs away from other foods. It’s a good idea to use your fridge’s egg tray, if you have one, because this helps to keep eggs separate.
  • Eggs can be eaten a few days after their best before date, as long as they are cooked thoroughly until both yolk and white are solid, or if they are used in dishes where they will be fully cooked, such as a cake.
  • If salmonella is present in eggs, it could multiply to high levels and cause food poisoning however salmonella contamination levels in UK-produced eggs is low, because of a vaccination programme.  Look for eggs withthe Lion Code quality assurance scheme.
  • Salmonella is killed by thorough cooking.
  • Avoid eggs with damaged shells as these may allow dirt or bacteria to get inside.

Foodborne pathogens

Bacteria and viruses are sometimes present in our food and are the most common causes of food poisoning. The most common foodborne pathogens implicated in foodborne illness in the UK are campylobacter, norovirus, salmonella, E. Coli O157 and listeria.


  • Campylobacter is the most common identified cause of food poisoning, causing over half of all estimated cases of food poisoning.
  • It is found mainly in poultry, unpasteurised milk and untreated water.
  • Campylobacter does not grow in food but it can survive if the food is not cooked properly.
  • If you’re not careful only a few bacteria in a piece of raw chicken could spread onto food that is ready-to-eat and cause food poisoning.


  • Salmonella is the second-most common cause of food poisoning after campylobacter.
  • It has been found in unpasteurised milk, meat, poultry, eggs and products containing raw egg.
  • Salmonella can survive if food isn’t cooked properly.
  • Salmonella can grow in food if the food isn’t chilled.
  • There only needs to be a small number of bacteria in a food for them to multiply.

E. Coli O157

  • Most strains of E. Coli are harmless, but certain strains such as E. Coli O157 can cause severe illness because they can produce toxins (called shiga toxins).
  • E. Coli O157 is carried by cattle and sheep and has been found in meat, dairy products and vegetables. It can be transmitted through eating of contaminated undercooked or ready-to-eat foods and through improper handling of contaminated food in the kitchen, leading to cross contamination to other ready-to-eat foods.
  • E. Coli O157 is also transmitted through non-foodborne routes such as by direct contact with people or animals that are infected, or with land contaminated with animal faeces.


  • Listeria is a food poisoning bacteria that can live and grow in food.
  • Listeria is mainly found in chilled foods such as pâté, cooked sliced meats, soft cheeses, smoked fish and pre-packed sandwiches.
  • Pregnant women, people over the age of 60 and anyone who is ill or who has a long-term medical condition are at a higher risk from listeria.

More on this topic


Food Safety

Food safety isn't just about eating out, it's about keeping you and your family safe in the home too.