Food Preservation

Food Preservation: Food items are prone to spoilage by microorganisms, there are methods by which food can be preserved for a longer time. Food preservation is the process of treating and handling food with an aim to stop or slow down its spoilage while maintaining its nutritional value, texture, and flavour. Since microorganisms are one of the major causes of food spoilage, food preservation involves creating conditions unfavorable for their growth. Food preservation methods either kill microbes or prevent their reproduction.

Different methods of food preservation and how it preserves food

Boiling: Boiling liquid food items can kill any existing microbes. Milk and water are often boiled to kill any harmful microbes that may be present in them.

Dehydration: Dehydration involves removal of water, one of the key requirements for microbial growth, from food items. Food items like cereals and pulses are generally dried under the sun to remove the moisture present in them.

Refrigeration and Freezing: Refrigeration at low temperatures and freezing help to preserve food for a longer time because microbes like bacteria and fungi cannot thrive at low temperatures. When fresh fruits and vegetables are frozen, water present in them also freezes. This helps in preventing microbial reproduction. Food items that can be preserved by freezing include meat and vegetable.

Canning: Storing food items in airtight cans is an effective way of preserving them. Food items like jams, vegetables, fish, and even cooked food are canned and sold in the market.

Using Chemical Preservatives: Any substance that helps preserve food or any other item is known as a preservative. Many chemicals help control microbial growth and are used as preservatives. Examples of chemical preservatives are sodium benzoate and potassium metabisulphite. These preservatives are used in squashes, sherbets, and ketchups.

Using salt sugar, oil, or vinegar: Salt, sugar, oil, and vinegar create an environment that prevents microbial growth, and are, therefore, used for preserving foodstuffs like meat pickles, jams, jellies, and vegetables. In addition to preserving foodstuffs, these substances also impart flavour to them.

Pasteurization: Pasteurization involves heating a foodstuff to a high temperature and then cooling it rapidly. This helps in destroying harmful microbes without changing the composition, flavour, or nutritive value of the foodstuff. This process is named after the French chemist Louis Pasteur, who discovered it in the 19th century. Commercially available milk is first heated to a high temperature for about half a minute and then cooled rapidly. It is then stored at temperatures lower than 10°C.

Sample Questions

(More Questions for each concept available in Login)

Question : 1

Which gas is used to preserve the packaged food (like potato chips etc)-
A. Hydrogen	B. Nitrogen	C. Ozone	D. Oxygen
Right Option : B
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Question : 2

The common preservative which reduces the moisture content to inhibit the growth of bacteria is :
A. Vinegar	B. Sugar	C. Sodium	D. Edible oil
Right Option : B
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Question : 3

Which of the given options would be the best explanation of "pasteurization"?
A. The process of heating milk at $70^0$ C for about 15 to 30 seconds and then rapidly cooling it.
B. The process of protecting food from the growth of microorganisms.
C. The process of converting a complex organic substances into simpler substance with the help of bacteria or yeast
D. The process of break down of organic matter from the dead bodies of plants and animals.
Right Option : A
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