Question

food preservation methods

Answer 1

Various Methods of Food Preservation:

1. Drying
2. Freezing
3. Radiation
4. Salting
5. Sugaring

Answer 2

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$\implies$What do you do with left-over food after dinner? You keep it in the refrigerator. Why? If left outside, the food can get spoilt and even cause food poisoning if consumed. So, to keep the food safe and keep it fit for consumption we need to preserve it. Some methods of preserving food are:—

➬ Refrigeration:— In a refrigerator, the low temperature reduces the rate of reproduction of microbes in food. This keeps food from spoiling far a few days.

➬ Dehydration or drying:— Food items can be dried in the sun or by spraying or freezing, although some nutrients are lost by this method. Drying commonly used for preserving fruits, cereals, pulses, etc.

➬ Addition of preservatives:— Some chemicals such as sodium benzoate and sodium metabisulphite can be added to the food items, to control the growth of microorganisms. These are called preservatives, commonly used in jams, squashes, etc.

• Oil and vinegar are used to preserve vegetables, fishes, pickles, etc., as they do not allow bacteria to grow.
• Salt and sugar cut down water available to microbes, thereby preventing their growth. Common salt is used to preserve pickles, chips, meat, etc. Sugar is used to preserve jams, jellies and squashes.

➬ Freezing:— Frozen food is very popular nowadays as it has greater shelf-life, without much loss of nutrients. In a freezer temperature and non-availability of water helps limit the growth of microbes

➬ Smoking:— Meat products are preserved by the process of smoking, which uses drying technique as well as smoke to keep meat from spoiling.

➬ Pasteurisation:— Factorization is a process in which microorganisms are destroyed by first subjecting them to high temperature and then sudden cooling. Milk is heated at 70°C temperature for about half a minute, and then suddenly cooled. This kills most of the bacteria. This processes used for the preservation of milk.

➬ Canning:— In this process, products are first subjected to high heat and then sealed in cans. While canning increases shelf life, care must be taken to ensure that the cans are not damaged. Any puffing or enlargement of cans would indicate spoilage.

➬ Sterilistaion:— In this process, ionizing radiations are used to destroy microorganisms without affecting heat-sensitive nutrients. This process is commonly used for the preservation of mushroom, strawberries, potatoes, etc.

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