Buying & Storing food (AQA GCSE Food Preparation & Nutrition)

Food safety: buying & storing food

• Food is often stored after buying and before eating

• It is essential that storage conditions are correct in order to reduce food spoilage and ensure that it is safe to eat

Temperature

• Storing food at the correct temperature slows down the rate at which food spoils; this is because it affects the rate at which microorganisms, e.g. bacteria, can grow and reproduce

Controlling temperature

• Temperatures to consider when planning the storage and preparation of food include:

• Perishable foods have a short shelf life and microorganisms can grow within them easily, e.g.

  • Meat

  • Fish

  • Dairy

  • Fruit and vegetables

• For perishable foods the temperature danger zone should be avoided as much as possible; this is why it is important not to reheat foods more than once

  • When food cools it passes back through the danger zone; repeating this process will increase the time during which microorganisms can reproduce inside the food

Ambient storage

• Some non-perishable foods can be safely stored at room temperature, also known as ambient temperature

  • Ambient temperature is generally between 17-20 °C

• The reason that non-perishable foods can be stored in this way is because they have been processed and/or packaged to prevent the growth of microorganisms, e.g.

  • Dried food has had its water content removed; this means that there is no moisture available for microorganisms

  • Tinned food has been heated to kill microorganisms and then sealed to prevent contamination

  • Vacuum-packed food has had the air removed from its packaging so no microorganisms can survive

  • Pickled foods are kept in vinegar where the low pH kills microorganisms

• Foods that can be stored at ambient temperatures include:

  • Bread

  • Dried pasta

  • Crisps

  • Cereal

  • Tinned fruit

  • Pickled onions

• Advice on the storage of eggs can vary depending on the way that eggs are processed:

  • In the UK chickens are vaccinated against salmonella and it is safe to store eggs at ambient temperature

  • In the US chickens are not vaccinated and eggs are washed, disrupting the natural protective layer around the egg shell and meaning that eggs need to be refrigerated

US Department of Agriculture, via Flickr

Fridges and freezers

• Food can be kept chilled or frozen by storing it in a fridge or freezer

• It is important to use fridges and freezers correctly to ensure safe food storage:

  • Fridges

    • Temperature should be between 0-5 °C

    • Food should be wrapped, covered or kept in separate containers to prevent cross-contamination

    • Hot food should be allowed to cool before being stored in the fridge so that the heat does not raise the fridge temperature

    • Raw and defrosting meat should be kept at the bottom of the fridge so that it does not drip on food below

  • Freezers

    • Temperature should be around -18 °C

    • Frozen food should be clearly labelled with the freezing date to ensure that it does not remain in the freezer for too long

    • Freezers should not be overfilled so that air can circulate easily between items

    • Food must be well wrapped to prevent loss of quality due to freezer burn

    • Frozen foods should be defrosted in the fridge and, once defrosted it should not be refrozen; this is because as soon as food enters the danger zone the dormant microorganisms will begin to grow again

US Department of Agriculture, via Rawpixel

Date marks

• Even when stored correctly foods will eventually spoil, and food producers often use date marks to indicate to consumers the date after which food is likely to have spoiled

• Date marks include:

  • best before date

    • This date relates to food quality

    • After the best before date there is a risk that quality will deteriorate, e.g. cereal may become stale

    • Eating food after this date is still likely to be safe

  • use by date

    • This date is more likely to be found on foods with a short shelf life, e.g. meat or fish, and it relates to food safety

    • Food consumed after the use by date carries an increased risk of food poisoning

Covering food

• Food should be covered when it is not being actively prepared or eaten; this applies when:

  • food is stored prior to cooking, e.g. in the fridge or the cupboard

  • food has been prepared and is not yet ready to be served

• Food is covered because of this:

  • prevents food from drying out

  • stops animal pests, e.g. flies, from accessing the food

  • prevents dust and dirt entering food

Mindaugas Skrupskelis, via Pexels