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The temperature danger zone for food describes the temperature range where food is most at risk of developing harmful bacteria. Food that is in the danger zone can cause illness to anyone who handles or consumes it. Ensuring that food is kept out of the danger zone limits the growth of bacteria, making it safe to eat. Leaving food at room temperature for too long can cause bacteria to grow at dangerous levels.
The Food Standards Agency (FSA) sets the temperature danger zone of food to be between 8°C and 60°C. This means that food is safest when it is either frozen or chilled below 8°C or heated beyond 60°C. The optimum temperature for bacteria growth is 37°C, which is the same temperature as the human body.
How to keep food out of the danger zone
Food safety is vital when cooking and preparing food, whether this is in a professional kitchen or cooking at home for your family. Knowing the correct temperatures when cooking and storing food, and staying out of the temperature danger zone, will help prevent food poisoning from occurring.
Harmful bacteria multiplies and grows at an extremely rapid rate between 8°C and 60°C. So much so, that restaurant food safety managers and government regulators have put measures in place to ensure food that is for public consumption, stays well outside of the danger zone temperature ranges. You should never leave food out of the fridge for more than two hours; however, if the temperature is above 33°C, food should be left out for no longer than one hour.
Before eating any leftover food, this should be reheated to a minimal internal temperature of 75°C. It is important to familiarise yourself with which foods are safe to be reheated, as some foods are not safe and you could be exposing yourself to dangerous bacteria and toxins. For further reading about what foods can be reheated, please visit our knowledge base.
Cold food should be kept cold and below 5°C. Food is safest when it has either been frozen, chilled or heated to the recommended temperature.
Some frozen goods such as ice cream will remain in a frozen state and therefore it is a simple process to ensure that it remains frozen. For other types of frozen food, you will need to follow the manufacturer’s guidance. Some food will be safe to be cooked from frozen and this will limit the amount of time the food is in the danger zone.
Other foods will need to be defrosted before cooking. These foods will need to be defrosted slowly in a cold environment. You can do this by leaving it in the fridge. Bringing the food from a frozen to a chilled temperature will ensure the food is not left in the temperature danger zone. For further reading about which foods can be safely cooked from frozen, please see our knowledge base.
Chilling food properly helps to stop harmful bacteria from growing. To keep your food safe:
- Store any food with a use-by date as well as cooked dishes, salads and dairy products in the fridge.
- Keep chilled food out of the fridge for the shortest time possible during preparation.
- Cool cooked food quickly at room temperature and put this in the fridge within one to two hours.
- Follow storage instructions on the packaging including the best before or use-by dates.
You must check that your fridge is cold enough by using the fridge thermometer. The fridge should be 5°C or below. You should not overfill your fridge as leaving some space between products allows the cold air to circulate and maintains the temperature you have set your fridge to.
Freezing food is an ideal option as food in the freezer will not deteriorate and most bacteria cannot grow in it. The cold temperatures in a freezer delay chemical reactions in food and stop any bacteria that may be present from growing. The bacteria will still be alive but they will not be able to multiply. You will be able to freeze pre-packaged food up to the use-by date. Leftovers should be frozen as soon as possible and warm dishes should be cooled before placing them in the freezer.
As the bacteria are still alive, it is important to remember that when you begin to defrost the food, the bacteria may begin to grow and can then cause food poisoning. This is why you should always defrost food in the fridge. This is also why food should not be refrozen once it has been defrosted. Once food has been defrosted, it should be eaten with 24 hours.
How to check food temperature
The most efficient way of checking the temperature of food which has been cooked or reheated is by using a probe thermometer. You insert the thermometer into the food using its metal stem. You should ensure you insert the probe into the middle of the dish and do not let it touch the pan as this will give an incorrect reading.
If checking the temperature of meat, the probe will need to be inserted into the thickest part of the meat as this will give the most accurate temperature. The temperature should be displayed on the probe screen and this will clearly indicate to you that the food is cooked to a safe temperature. After use, the probe must be cleaned and disinfected in order to avoid the spread of bacteria.
When cooking meat, there are other ways to ensure that it is cooked. This can include checking the colour of the meat whilst cooking. For example, chicken will turn from pink to white and beef will turn from red to brown. When cooking any meat, make sure it is steaming hot and cooked all the way through.
You can cut the thickest part of the meat to make sure that the juices run clear and none of the meat is pink. When cooking a chicken or turkey, you should cook the stuffing separately and not inside. This is because when it is stuffed it will take longer to cook and may not cook all the way through.
When cooking other food products, you may notice things like a change in texture, for example potatoes will go from hard to soft.
For frozen and chilled foods, you can also use a probe thermometer to check the temperature. You can also use an infrared thermometer which can be useful when accepting a delivery of frozen goods. If keeping food frozen or chilled, the best way to monitor that it is at a safe temperature is to monitor the temperature of the fridge or freezer as most will have an electronic monitor built in and on display.
You can access a helpful guide about checking the temperature of food from the Food Standards Agency.
How long should you cook food for?
Cooking is important to safely remove bacteria from food. In order to do this, you must cook to a high temperature for a certain length of time. The Food Standards Agency (FSA) in England recommend that food is cooked to a temperature of 70°C. In Scotland, it is recommended that food is cooked to a temperature of 82°C. It is also important how long food remains at this temperature.
The FSA states that food cooked to a temperature of 60°C must remain at that temperature for 45 minutes, which would not be practical in many circumstances. However, food that is cooked or heated to a temperature of 65°C needs to remain at that temperature for 10 minutes. Food cooked to a temperature of 70°C, only needs to remain at that temperature for 2 minutes to ensure that it is safe to eat.
If food is cooked to a temperature of 75°C it only needs to remain at that temperature for 30 seconds, and food cooked to a temperature of 80°C only needs to remain at that temperature for 6 seconds in order to ensure that it is safe to eat.
What is the temperature range of the danger zone?
The danger zone is the temperature range that it is dangerous for food to be left at. This range is between 8°C and 60°C. Bacteria can grow rapidly between 8°C and 60°C and bacteria can double in amount every 20 minutes. The amount of time food spends in the danger zone must be minimised and food must also be moved through the danger zone as few times as possible when reheating or cooling.
What is the temperature danger zone for bacterial growth?
Many foods offer the perfect environment for bacteria to grow. The main types of bacteria include:
- Campylobacter – This type of bacteria is reportedly present in 76% of supermarket chickens and on 6% of the exterior of supermarket chicken packaging. Campylobacter is also commonly found in unpasteurised milk.
- Salmonella – Most commonly found in raw egg, milk and other dairy products as well as raw and undercooked meats.
- Listeria – Many pre-packaged convenience foods contain listeria, such as sandwiches and cooked meats. It is important to look at the recommended use-by dates.
These are just a few of the most common bacteria found to cause food poisoning; however, there are many more which can cause food poisoning as a result of reheating food incorrectly.
The temperature danger zone is 8°C–60°C and given the right circumstances and type of food, bacteria can continue to double in amount every 20 minutes. One of the most common causes of food borne illness is the incorrect cooling of cooked foods.
Harmful bacteria are one of the main sources of food poisoning. Most people will experience mild symptoms; however, in some cases food poisoning can be severe. Anyone who consumes food where bacteria are present is at risk of food poisoning; however, some individuals are at more risk than others. This includes people with weaker immune systems, young children, older adults and pregnant women. This group of people are at risk even when only small amounts of bacteria are present.
Common symptoms of food poisoning can include:
- Stomach cramps.
- Intense sickness and nausea.
In order to reduce the risk of food poisoning, it is important to keep food out of the temperature danger zone. This includes reheating leftover food to a minimum temperature of 70°C and refrigerating food at or below 5°C within two hours of it being left out, or one hour if the temperature is 35°C or warmer out.
Food poisoning can also occur if food has not been stored correctly, for example, it has not been frozen or chilled, has been left out for too long, has been handled by someone who is unwell or who has not washed their hands, or the food has been consumed after its use-by date.
The NHS have some useful tips on how to avoid food poisoning.
High-risk foods are foods that are moist, high in starch or protein or have neutral acidity (pH over 4.5).
Examples of high-risk foods include:
- Meat and poultry.
- Dairy products.
Raw vegetables and fruit can also be considered as high-risk foods as they can support the growth of pathogenic microorganisms. This is especially those that won’t be cooked. Fruits and vegetables can become contaminated if they come into contact with contaminated water, surfaces or equipment, other contaminated food, pests or food handlers who are sick or who have dirty hands.
High-risk foods need to be monitored closely with regards to time and temperature in order to stop bacteria from growing, as high levels of bacteria and toxins in food can cause food poisoning. Spores protect some types of bacteria from high temperatures, which makes it far more difficult for them to be destroyed during cooking.
Other pathogenic microorganisms like viruses or parasites don’t grow in food, but they can contaminate it. Eating undercooked meat products is the most common cause of parasite infection.
People can also get parasites from contaminated water or food which has been washed in contaminated water, or through cross-contamination with other foods or surfaces. Cooking is the most effective way to control the spread of parasites therefore it is important to know the safe cooking temperatures for the types of food you are preparing.