Handling food in the home

In this article

  1. A guide to shopping
  2. A guide to storing food
  3. Precautions during food preparation

A guide to storing food

Page 2 of 3

 Refrigerator guide

Perishable non-frozen foods

Refrigeration can substantially reduce the rate at which food will deteriorate. Low temperatures slow down the growth of micro-organisms and the rate of chemical changes in food.

The temperature in a frost-free refrigerator is fairly even. However in a moist air refrigerator the coolest part of the refrigerator is near the coils.

Thermometers made especially for refrigerators and freezers are available from some department stores and are a worthwhile investment.

Uncooked minced meat, liver, kidneys, poultry and seafoods need careful storage because they always carry large numbers of spoilage and possibly food poisoning micro-organisms. Some of these micro-organisms can grow even at refrigeration temperatures, so always store these foods in the coldest part of the refrigerator as close as possible to 0 °C.

The longest recommended storage time is three days. To kill any food poisoning bacteria which may be present, always cook minced meat thoroughly to a temperature above 75 °C.

Recommended refrigeration storage temperatures for some foods
Food storage temperature °C Shelf life in the home
Seafoods 0-3 3 days
Crustaceans and molluscs 0-3 2 days
Meat 0-3 3-5 days
Minced meat and offal 0-3 2-3 days
Cured meat 0-3 2-3 weeks
Poultry 0-3 3 days
Fruit juices 0-7 7-14 days
Milk 1-7 5-7 days
Cream 1-7 5 days
Cheese 0-7 variable (1-3 months)
Butter 0-7 8 weeks
Oil & Fat 2-7 variable (6 months)
Margarine 2-7 variable (6 months)
Chilled meats and meal components 0-3 no longer than 'use by' date
Leftovers 0-3 3-5 days

Wrapped fresh meat can be kept safely for up to three days and unwrapped fresh meat up to five days at cold temperatures 0°-3 °C.

Whole red meats (e.g. leg of lamb) and cured meats have a longer storage life, and unwrapped meats last longer than wrapped meats.

Wrapped meat maintains its original high water content and quality but surface growth of micro-organisms is encouraged and the meat becomes slimy after about three days and an 'off' odour can become apparent. The safe thing to do then is to throw it out.

Unwrapped meat keeps longer - fresh meat for up to five days and cured meat for up to three weeks at 0° -3 °C. The meat surface dries out. This retards microbial growth but causes undesirable colour changes and loss of flavour. However, this is preferable to meat going off because it is wrapped. But be sure to expose all surfaces in turn.

Refrigeration hints

Throw out food which is going off because putting it in a colder part of the refrigerator will not stop it deteriorating further. It can taint other food.

Store food you want to keep for a long time, or items like seafoods which are quite susceptible to spoilage, in the coldest part of the refrigerator. Cover all cooked foods and store them on a shelf above uncooked goods. This minimises the risk of food poisoning organisms being transferred from uncooked to cooked foods through drip.

Foods with strong odours, such as seafoods and some cheeses, should be wrapped, and you should avoid storing them for long periods near food such as milk and cream which are susceptible to tainting.

Some flexible films are effective barriers to the transmission of odours but they are not readily available to consumers. The common cling wrap polyethylene films are not very effective, but they are useful in the short term and stop spillages. Closed glass or plastic containers are preferable.

 Frozen foods

Freezing food and holding it at a very low temperature, around -18°C, almost completely stops deterioration. Thawing or even a rise in temperature without thawing stimulates chemical and microbiological activity and spoilage may occur.

Remember, frozen foods should be put in the freezer section of the refrigerator (or the freezer) as soon as you get home from the shop.

Long-term storage of commercially frozen foods in the home with an ordinary refrigerator is hard to justify. It is better to buy frozen foods as required because some home freezers do not hold food at a sufficiently low temperature to maintain high quality over a long period. Small quantities of bought food can, however, be held frozen for a few weeks at temperatures of between -15 °C and -12 °C without serious loss of quality.

People who freeze their own garden produce are in a somewhat different position as they have full knowledge of the storage history of the frozen product.

Cooking hints for frozen foods

Some frozen foods, particularly vegetables, should be used direct from the frozen state. Frozen vegetables usually have been blanched before freezing and need only be lightly cooked before serving.

Dehydrated foods do not readily go bad while dry, but they are deteriorating slowly all the time, particularly once the packets are open to the air.

Large cuts of frozen meat and poultry need to be thawed before use. This should be done in the refrigerator at a temperature below 4 °C to stop the growth of food poisoning bacteria. At least 24 to 48 hours in the refrigerator is usually required to thaw reasonably sized portions of foods such as whole chickens or rolled roasts. Special care is necessary when thawing and cooking turkeys or large pieces of meat - more than 3 kg.

If frozen meat has to be used at short notice it should still be thawed before cooking. This can be done under cool running water without unwrapping the meat or in a microwave oven. However, if you have to cook the meat before it has completely thawed, allow extra cooking time and ensure (by using a good meat thermometer) that the temperature in the middle of the joint has reached 71 °C.

Smaller cuts of meat such as steaks and chops can be fried or grilled direct from the frozen state.

Generally speaking, thawed food should not be refrozen. It can be stored safely in the chilling section of the refrigerator for up to 48 hours if it has been thawed properly under controlled conditions in the refrigerator.

Warning: It is bad practice to thaw meat, poultry or fish out of the refrigerator. If this has been done it should never be put back into the refrigerator for use later. If it cannot be cooked immediately it should be thrown away because there has been an opportunity for food poisoning organisms to grow.

 Dehydrated or dried foods

Dehydrated foods do not readily go bad while dry, but they are deteriorating slowly all the time, particularly once the packets are open to the air.

Dehydration inhibits the growth of microbes by removing water but it does not make foods sterile and these foods may carry a high level of contaminating micro-organisms which become active again in the presence of water.

Rehydrated dried foods - those to which water has been added - need to be treated as highly perishable and kept in the refrigerator.

Storage of dried foods

Store in a cool place away from obvious sources of heat such as a stove or direct sunlight. Dried foods will keep in an unopened container for about six months at 21° - 24 °C.

Inspect regularly for insect infestation as this is a constant problem.

If possible store opened packages or dried fruits in the refrigerator to maintain quality for a longer period.

Savoury dips made from dehydrated ingredients should be kept in the refrigerator. Once the powder is combined with other moist ingredients conditions are right for the growth of bacteria.

Stocks, soups, sauces and gravies made from dehydrated ingredients should also be kept in the refrigerator.

 Canned foods

Most canned foods have been sterilised during processing, which means any contaminating organisms originally present on the food have been destroyed and the cans need only be stored in a cool place. But watch for swollen or leaking cans. This indicates some failure in processing and the contents of the can should not be tasted. Any doubtful can should be reported to the manufacturer to alert them that other cans may be in a similar condition.

Any products, such as canned meats and fish, which are marked `Store below 4° C' must be stored in the refrigerator. The contents have not been fully sterilised because prolonged heating adversely affects the texture. All labels should be read carefully before the food is stored.

Once opened

Adopt the same storage precautions for the contents of a can as you would for fresh food of the same kind. This is because contamination is possible as soon as the can is opened and some of the contents removed.

Throw out the contents of any can which have any unusual odour. Some foods may be stored in the can in the refrigerator and partly used cans should be covered with plastic. However, there are some preserved foods which do not store well in cans. Highly acid or salted foods such as fruit juices or tomato products do attack tinplate in the presence of air and they should be transferred to a glass or plastic container before refrigerating.

Storage life

Unopened canned foods can be stored at 21°-24°C for at least 12 months.

Many canned foods will keep longer but because of uncertainty as to the true age of the food a 12-month maximum should be set.

Canned rhubarb, fruit juices, soft drinks and some baby foods are exceptions and have a maximum storage life of about six months.