Follow the instructions
Q Why do some frozen foods say 'cook from frozen' and others 'defrost then cook'?
A Cooking instructions are put on food labels for two main reasons - to help ensure that the food will be thoroughly cooked and also be enjoyable to eat.
Freezing doesn't affect the safety of food because bacteria can't grow at very cold temperatures.
When food is labelled as suitable for cooking from frozen, it is safe to do this as long as you follow the instructions and make sure the food is piping hot all the way before you serve it.
However, freezing can affect the quality of food, for example, the appearance, texture and flavour. These effects will vary depending on the food and how long it is frozen.
With some products, a manufacturer might decide that the food will be of a better quality if it is defrosted before cooking. Other products might be as good to eat, or better, if they are cooked from frozen.
So quality will usually be the main concern for a manufacturer when it decides whether to advise defrosting before cooking, or not.
It's important to follow the defrosting and cooking instructions on packaging because they are designed to make sure the food is cooked thoroughly.
For example, if the label gives a cooking time for defrosted food and you cook it from frozen, you won't know how long to cook it for to make sure it is properly cooked.
If you leave food to defrost for a long time at room temperature, this could allow bacteria to grow in the food.
These will usually be killed by thorough cooking, but if the food is undercooked the bacteria could survive and make you ill.
That is why you should always make sure that food is piping hot all the way through before you eat it.
Sam Montel is the Food Standards Agency's online nutrition expert and a registered public health nutritionist.
She will be answering a different question about healthy eating every week. To find out more about food, visit the Food Standards Agency's website at www.eatwell.gov.uk
