Selasa, 01 November 2011

Ways of Preserving Food



Looking around at the food store, you might glance at all the food items in wax packaging, seafood packaging and poultry boxes, and wonder how people preserve food. No one exactly knows how we learned it or how we got the idea that food might be preserved. However, whatever the reason might be, we do know that people for centuries have preserved food. How do they do it? Let us take a look.
1. Drying:
This is the oldest method of conserving food. Since a long time, people have been drying herbs, meat, fruits and vegetables. Today, this method is mainly used to conserve meat. The process of drying reduces moisture content from the food. Because moisture is one of the basic requirements for bacterial growth, reduction in moisture means bacterial growth is stopped. The process uses sun drying, oven drying, air drying, baking and dehydrator drying.
2. Freezing:
All microorganisms require a particular temperature range for their survival. Above and below this temperature, survival is not possible. Using this method, the temperature is lowered to such a degree that microorganisms cannot survive. Refrigerators and cold stores work using this method.
3. Canning:
Canning shields the food from microorganisms through two main processes. First, the food is processed. During the processing of food, microorganisms are killed. Afterwards, the food is kept in airtight cans and saved from the entry of microbes. Methods involved in processing the food are pasteurization, boiling, freezing or vacuum treatment.
4. Vacuum treatment:
Bacteria and other microbes will require oxygen for growth. With the help of this treatment, oxygen is removed from the air tight containers. As oxygen is removed, the growth of these microbes is brought to a standstill. Mainly nuts, grapes in bran, and eggs in lime water are preserved using this method.
5. Salting:
Salt is a natural food preservative. Using salt finishes moisture from the food and also from the cells of microbial bodies. As a result, this kills bacteria and saves the food. Normally, meat is prevented from spoilage through this method.
6. Pickling:
Normally, vegetables such as cucumbers and onions are preserved with the help of this method. The food item is immersed in a preserving liquid that will inhibit microbial growth, but will still keep the food edible. Some common liquid chemicals are vinegar, alcohol, and some oils. Pickling might also be done through fermentation. During fermentation, alcohol is produced as a by-product. This alcohol can be utilized as the preserving agent.
7. Sugaring:
This method is used to preserve sweet food items. Usually, this method is used to preserve apples, apricots and plums. A sugary syrup is used which dehydrates the food material. Another way is to cook the skin of certain fruits in sugar until they crystallize. Later, they can be placed in a dry environment. However, this method might not be very reliable. Since sugar itself draws moisture, it is likely that as soon as the moisture levels inside the food rise, they will support microbial growth inside. Jellies, marmalades, and candied fruits are preserved using this method.
Published At: Isnare.com

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