Oxidation and dehydration also contribute to spoilage. Food preservation therefore aims to alter the condition of food to stop the activities of microorganisms and any chemical change. Freezing is now widely used for both industrial and domestic food preservation. Freeze drying involves freezing followed by dehydration, usually in a vacuum. Heating kills mircoorganisms and is the principle of pasteurization , sterilization , etc.
Smoking is used to preserve meat and fish.
In food irradiation gamma radiation is used to kill microorganisms, insects, etc. The sale of irradiated food was legalized in the UK in 1991. The Macmillan Encyclopedia 2001 3. freeze drying The Macmillan Encyclopedia 2001 4. canning Oxford Paperback Encyclopedia 5. All rights reserved.