Material:

Source:

Advantages:

Disadvantages:

Used for:

Paper

Wood

Can be waxed to make it waterproof, easy to print on, cheap, can be recycled.

Not very strong.

Flour, sugar, loose fruit and vegetables.

Cardboard

Wood

Lightweight, easily shaped, easy to print on, can be recycled.

Soggy if wet.

Frozen foods, cereals, cakes, fruit juice.

Glass

Sand

See-through, can be coloured, cheap, can be recycled, easily moulded.

Can break easily. Often needs a paper or plastic film label. Heavy.

Jam, wine, pickles, milk, cooking sauces.

Metal (Tinplate and aluminium)

Ores

Heat treated to preserve the contents, can be recycled, strong, lightweight.

Can rip (foil lids), often needs a utensil to open it, needs a paper label. Heat treatment can alter texture and taste.

Yoghurt lids, tinned foods, bottle tops.

Method and
How it works:

Advantages:

Disadvantages:

Used for:

Canning:
Heat kills bacteria and enzymes.

Lasts for many years.

Can cause changes in colour and texture. Loss of Vitamin C.

Fish, meat, fruit, vegetables, milk.

Bottling:
Heat kills bacteria and enzymes.

Lasts for many years.

Can cause changes in colour and texture. Loss of Vitamin C.

Fruit and vegetables.

Pasteurisation:
Most bacteria killed at 72 degrees Celsius.

Little effect on flavour.

Not all bacteria killed.

Milk, cream, orange juice.

UHT:
All bacteria killed at 132 degrees Celsius.

Lasts for several months.

Changes taste slightly.

Milk, fruit juices.

Sterilisation:
Food is heated to 104 degrees Celsius for 40 minutes.

Extends life of milk to about 10 days.

Gives a creamy flavour and colour.

Milk, fruit juices.

Freezing:
Stops bacteria and enzymes activity. Domestic freezers are at -18 degrees Celsius.

Foods can be frozen for many months. Little loss of vitamins.

Slow freezing breaks down cells and changes the texture of foods.

Ready prepared meals, fish, meat, vegetables, fruit, ice-creams.

Chilling:
Temperatures of 1 to 8 degrees Celsius slow bacteria growth.

Good colour and flavour kept.

Short storage life.

Ready prepared meals, such as Lasagne.

Drying:
Removal of moisture stops bacteria growth.

Last for long periods of time.

Most Vitamin C lost. Must be kept dry.

Soups, pasta, beans packet desserts.

AFD:
Food is frozen and then dried quickly.

Good colour and flavour.

Can be expensive.

Coffee.

Pickling:
Increases acidity of food.

Long shelf life.

Very strong flavour.

Onions, cabbage, olives.

Salting:
Reduces water content by osmosis.

Long shelf life.

Food needs to be soaked before cooking.

Meat, fish, green beans.

Smoking:
Slow method, which prevents bacteria growth.

Adds flavour.

Kills Vitamins B and C.

Bacon, cheese, fish.

Sugar:
More than 60% will stop micro-organism growth.

Long shelf life.

High temperatures in jam making kill Vitamin C.

Jams, marmalade, crystallised fruits.

Vacuum packs:
Removes all oxygen.

Retains vitamins.

Often still needs refrigeration

Bacon, fish.

MAP:
Replaces oxygen with nitrogen and carbon dioxide.

Colour and flavour are good.

Expensive.

Meat, salads, minced beef, and bacon.

Irradiation:
Radiation kills, bacteria and pests.

Delays ripening of fruit and sprouting of vegetables.

Not in general use. Consumer safety worries.

Strawberries, vegetables and spices.