Quick freezing is the term used by com-mercial processors for the preservation of food by freezing – as compared with the slower process of ‘fast’ freezing when FREEZING food at home.
Quick freezing stops the natural decay of food by slowing down chemical changes and enzymatic activity so that the food, after freezing, can be stored at low temperatures for long periods, by the processors, without deterioration.
Quick freezing reduces the temperature of food very quickly from 30°F (-1°C) to 23°F (-5°C). It is in this critical temperature range, when water in the food is freezing, that the water pressure within the cells, and in the space between the cells of the food is disturbed. The quicker the food is reduced in temperature, the better the retention of the original texture, flavour, colour and nutritional value.
After passing through this critical temperature range, food is further lowered in temperature to about -25°F (-32°C) and then stored in large factory coldstores. Quick freezing requires refrigeration plant capable of very high rates of heat extraction at temperatures as cold as -40’F (-40°C).
Quick freezing was first developed as a commercial method of natural food preservation by Clarence Birdseye, an American scientist and explorer, in 1924. When he was in the Arctic he noticed that fish caught and frozen naturally for long periods of time in the very low temperature, remained as fresh as fish caught and eaten the same day. His discovery and use of mechanical refrigeration plant, to reproduce similar Arctic temperatures, was the beginning of the vast quick frozen food industry of today.