Back to: Food and Nutrition SS 2
Food preservation is a term that refers to a variety of techniques for keeping food from spoiling after it has been harvested or slaughtered. Such customs can be traced back to primordial times. Food preservation is the procedure by which food is treated and handled to stop or slow down food spoilage, loss of quality, edibility, or nutritional value and thus allow for longer food storage.
Preservation usually involves preventing bacteria, fungi (such as yeasts), and other microorganisms from developing, as well as retarding the oxidation of rancid-causing fats.
Drying, refrigeration, and fermentation are some of the oldest methods of preservation. Canning, pasteurisation, freezing, irradiation, and chemical addition are all examples of modern processes. Modern food preservation has benefited greatly from advancements in packaging materials.
Drying
Drying is one of the most ancient techniques of food preservation which reduces water activity enough to prevent bacterial growth.
Refrigeration
Refrigeration preserves food by slowing down microorganism growth and reproduction and the action of enzymes that cause food to rot.
Freezing
It is also one of the most frequently used processes for preserving a wide range of foods, including prepared foods that in their unprepared state would not require freezing.
Salting
The salting or curing process removes moisture from the meat through an osmosis process. Meat is salted or cured with sugar, or a combination of the two. Nitrates and nitrites are also widely used to treat meat, leading to the distinctive pink colour and inhibiting Clostridium botulinum.
Crystallisation
Sugar is used to maintain fruits, either in fruit syrup such as apples, peaches, apricots, or in a crystallised form where the preserved material is cooked in sugar to the point of crystallisation and the resulting product is then stored in a dry place.
This method is used for citrus (candied peel), angelica, and ginger skins. An alteration of this process creates glacé fruit, such as glacé cherries, in which the fruit is preserved in sugar but then extracted from the syrup and sold, preserving the fruit sugar content and superficial syrup coating.
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