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Home food fact checker

Knowing how to store, cook and reheat food at home helps improve food safety and reduce food waste. This page has advice on some common household food safety questions like the sniff test and the egg float test.

Last updated: 10 June 2022
See all updates
Last updated: 10 June 2022
See all updates

Here we answer some of the most common food safety questions we get asked about different types of food.

FSA Explains
There are a number of myths and misconceptions about how long you can store food, when you know it’s gone off, and how to keep your food safe at home. By fact-checking the most common questions, we hope this will help you to stay safe and avoid throwing away good food unnecessarily.


Does the sniff test work for milk and dairy food?

It's not safe to use the sniff test for any food with a use-by date.  The sniff test won't work as you can't smell the bugs that cause food poisoning.

Milk and some other dairy products like yoghurt can have either a use-by date or a best before date.  The manufacturer decides which date marking is the best for the food they produce.  Whether these foods have a use-by or best before date is down to the manufacturer and the way the food is processed.

If a food has a best before date the sniff test can be used - the best before date is about quality, not safety.   You can smell food with a best before date to see if it has spoiled.  You can also use visual cues, such as whether you can see mould or if there are any changes to texture.  Food with best before can be eaten after the date on the pack, however they may not taste as good as they did before.

It's always better to check the storage, use-by and best before dates when you buy food so you can help ensure it's safe and to prevent waste.

For more on the sniff test and date markings please visit our page on best before and use-by dates.


How long can you safely eat rice for after cooking?

Rice may be eaten cold if it is cooled down quickly. Put the rice in the fridge and consume within 24 hours.

You can get food poisoning from eating reheated rice. It's not the reheating that causes the problem, but the way the rice has been stored before it's reheated.

Keep rice in the fridge for no more than one day until reheating. When you reheat any rice always check the dish is steaming hot all the way through. 

Uncooked rice can contain spores of a bacterium called Bacillus cereus. This bacteria can cause food poisoning. The spores of Bacillus cereus can survive being cooked. The longer cooked rice is left at room temperature, the more likely it is that the bacteria or toxins will make the rice unsafe to eat.

Can you reheat rice?

Yes, but you should never reheat rice more than once.  And when you do reheat rice, make sure it is steaming hot all the way through.

If you have leftover rice you should chill it as quickly as possible, ideally within one hour. Dividing it into smaller portions can help with this. Also don't leave rice in the rice cooker, steamer or pan to cool down.

Can you reheat takeaway rice?

You should never reheat rice more than once. Extra care should be taken with takeaway rice. Ideally, takeaway rice should be eaten shortly after purchase or shortly after it has been delivered.

This is because some food businesses may pre-cook their rice and then re-heat it before it is given to customers. Whether it is safe to reheat the cooked rice will depend on how it was stored, handled and if it was cooked outright in the first place. It’s always worth asking the takeaway business how they handle the rice.

Can you freeze rice?

You can freeze rice but should cool the rice quickly before putting it in the freezer, and if you portion it out into smaller containers this will help chill it faster. To do this you could place the container of rice in cold water and once cool, cover and store it in the freezer. By making sure rice goes in the freezer within an hour of cooking, you will stop bacteria multiplying and producing a toxin. Before eating, you should defrost your rice in the fridge and then reheat it until it is steaming hot before eating immediately.


Does the egg float test work?

We do not suggest using the egg float test to show whether the eggs are safe as it assesses age, not safety.  The float test can't show you which bacteria have been growing inside the egg.  The egg floats because more air gets inside the older it gets, so it's an indicator of age, not safety.

Are eggs safe to eat after the best before date?

Eggs are safe to eat for a couple of days after the best before date if they are cooked well. The best before date should be stamped on the egg. You should make sure both the white and yolk of the egg are cooked thoroughly. You can use eggs a couple of days after the best before date in cooking or baking.

Are raw eggs safe to eat?

There have been improved food safety controls in the UK hen egg industry in recent years. So infants, children, people who are pregnant, and people aged 65 or over can now safely eat raw or lightly cooked hen eggs, or foods containing them if they have a British Lion mark or are produced under the Laid in Britain egg assurance scheme.

This advice does not apply to individuals who are severely immunocompromised and require medically supervised diets prescribed by health professionals.

This advice remains valid during outbreaks of Avian Influenza, also known as Bird flu. Bird flu poses a very low food safety risk for consumers and does not change our advice on consumption of eggs. The Department for Environment, Food and Rural Affairs (DEFRA) has further advice on Avian Influenza.

Northern Ireland

For Northern Ireland-specific advice on Bird Flu, please refer to the Department of Agriculture, Environment and Rural Affairs (DAERA).

Should you store eggs in the fridge?

Eggs should be stored in a cool, dry place. Ideally, eggs should be stored in the fridge. The storage area should be cleaned regularly. Follow the manufacturer’s advice and avoid storing eggs where they would be exposed to extreme temperature changes. Temperature changes can lead to condensation on the surface, which causes increased penetration of Salmonella from the outside of the shell into the egg.

Can I freeze eggs?

Eggs can be frozen and used safely at a later date. Simply crack your eggs into a container, seal and freeze. You can separate yolks from whites first if you prefer and then put them into separate containers.

Label the containers so you can easily identify them when you wish to use them. You can also crack the egg into a sealable container and beat it before freezing. This can be easily used to make scrambled eggs or an omelette.


Can you eat brown bananas?

Fruit that is a bit overripe, such as brown bananas, wrinkly apples and slightly mushy strawberries, can be eaten normally, as long as they don’t contain any mould. Overripe fruit is great for cooking, baking and made into smoothies. 

Should you wash fruit?

Remember to wash fruit and vegetables with water before you eat them. This is to make sure that they are clean and harmful bacteria can be removed from the outside. You should wash them under a running tap, or in a bowl of fresh water, making sure to rub their skin under the water. You can start with the least soiled items first and give each of them a final rinse.

Can you still eat food if you remove the mouldy part?

Food that is obviously rotten or containing mould should not be eaten. This is due to potential risks from the mould. This advice is especially important for people in vulnerable groups. This includes children, people who are pregnant, people aged 65, and those who have a weakened immune system.

While it is possible that removing the mould and a significant amount of the surrounding product could remove any unseen toxins that are present, there is no guarantee that doing so would remove them all.


Can you eat potatoes when they go green and start to sprout?

If potatoes have sprouted, simply remove the sprouts before use. Remember to cut off any green or rotten bits before using.

Green bits on potatoes can contain high levels of natural toxins called glycoalkaloids which are usually found in potatoes at low levels, but they can be higher in:

  • green parts
  • damaged parts
  • sprouted parts

High levels of glycoalkaloids can upset the digestive system and cause symptoms such as abdominal pain, vomiting and diarrhoea. However, glycoalkaloid poisoning is extremely rare, even though potatoes are eaten in very large amounts in many countries.

To avoid high levels of glycoalkaloids being produced in potatoes, store them in a cool, dark and dry place.

Can potatoes be frozen?

You can freeze cooked or parboiled potatoes which have been boiled for 5 minutes. Leftover cooked potatoes can also be frozen. You can roast boiled potatoes straight from the freezer, make sure they are steaming hot all the way through. Put them in the oven with a little oil to crisp up. 

Can you store potatoes in the fridge?

Yes, if you wish to help avoid food waste, you can choose to store potatoes either in the fridge or in a cool, dark, dry place.

A recent study, which has been reviewed by the Committee on the Toxicity of Chemicals in Food, Consumer Products and the Environment (COT), has shown that home storage of potatoes in the fridge doesn’t materially increase acrylamide forming sugars, known as cold sweetening, when compared to storage in a cool, dark place. 

How long can you eat vegetables after their best before date?

Vegetables past their best before date may become wrinkly or mushy, but are safe to eat as long as there is no visible sign of decay. Make sure to check for rotting or mould before eating.

The best before date is about quality, not safety. Food will be safe to eat after the best before date but may not be at its best. The length of time vegetables are acceptable to eat after a best before date can depend on the product and the storage instructions.

WRAP’s food storage A to Z tool offers advice for different foods after the best before date.

Are raw kidney beans poisonous?

Canned beans purchased in the supermarket are safe to consume as they have been pre-soaked and boiled to kill any toxins present.

Raw or undercooked beans especially red kidney beans can be risky. This is because they naturally contain a type of lectin that can produce toxic effects. You should not slow cook raw red kidney beans as it does not destroy the toxin and may increase its toxicity.


Is it safe to reheat meat in the microwave?

You can reheat meat in a microwave once. Make sure that it is steaming hot all the way through before eating. It is best to use small pieces of meat, as large pieces may dry out in some places while others may not be thoroughly heated.

It is a good idea to stir food while it is reheating. When food is microwaved it can be very hot at the edges and still be cold in the centre, stirring helps to prevent this.

If you are reheating a food product in a microwave, follow the manufacturer’s instructions on the packaging, including advice on standing and stirring. Standing and stirring are part of the process of cooking and reheating in a microwave. This will help to make sure that food is the same temperature all the way through.

Can you reheat meat more than once?

Previously cooked and frozen meat should only be reheated once. 

Tinned or canned food

Is food safe if the can has a dent in it?

Food should remain fit to eat if a can is dented, providing the denting of the can is shallow and there are no other obvious signs that the can is damaged.

However, if the denting is deep, the can may have a hidden split, hole or break in the seal. This could result in a can that is no longer a reliable container. If this is the case, the food inside should not be eaten. If the denting has caused the can to rust, the food inside should not be consumed either.

You should avoid eating food from a visibly bulging can. If the can spurts when it is opened, this may be a result of gas build up in the food. This could be due to the presence and growth of microorganisms. These microorganisms can spoil the food and can make it unsafe. If consumers have purchased cans which are visibly bulging, they should return them to the retailer.

How long can canned food be eaten after the best before date?

The length of time canned food is acceptable to eat after a best before date depend on the product, storage conditions and the brand.

Follow the manufacturer’s instructions on the ‘open life’. This usually indicates where to store products and for how long. Different brands of the same products can undergo different manufacturing processes. This can affect their composition and how perishable they are.

Can you eat canned food cold?

Many canned foods intended to be heated before eating will not pose a safety risk if eaten cold. However, this will depend on the product. Always follow the manufacturer's instructions before eating. 

Is it safe to leave food in opened cans?

You should not store food in an opened tin can. When a can has been opened and the food is exposed to the air, the tin from the can could transfer more quickly to the food inside. 

After opening a can of food, if you aren't going to use it all right away, empty the contents into a bowl or another container and put it in the fridge.

This advice does not apply to foods sold in cans with resealable lids, such as cocoa and golden syrup, as they do not react with the can.