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Food Spoilage And Principle Of Food Preservation

Good Health is direct related to fresh or good food. Spoilage food show bad effect on health it cause many series disease. What is food spoilage. Answer of this question we can say it is deterioration of the colour, flavour, odour or consistency of food product due to agents which makes it unacceptable for human consumption.

What causes food spoilage?

The three main cause of food spoilage are:

  • Micro-organism
  • Enzyme action
  • Insect and rodent damage


Micro-organism such as bacteria in food spoilage. They cause moudling, fermentation and putrefaction in food. These micro-organism are usually found on the skin or outer layer of food and they penetrate inside the food only when the outer covering has been broken.

Enzyme action:

All fresh food also contain enzyme. Also found in fruit and vegetables. They are very important for riping of fruit and vegetables. However, this action of enzyme continues after the fruit/vegetable have become fully ripe. It brings about undesirable change in food. You must have observed the darkining of cut surface, development of soft spots and offensive flavour in fruit and vegetables. Enzyme caused initial say. Micro-organism can grow on such damaged vegetables tissue causing fermentation.

Insect and rodent damage:

You know that rodents, worms, weevils, bugs, fruit flies and moths damage food. They not only eat away food but spoil it by their excreta. You must have observed the cuts and bruises caused by these worms and insects on food which serve as pathways by which micro-organism reach the interior of the food.

Principle of Food Preservation:

Various reason which are essential for food preservation.

  • Preserved food could be stored for long time.
  • We can prevent contamination of food by good preservation method.
  • Micro-organism can remove by using filtration technique.
  • By the use of heat killing the bacteria or other micro-organism.
  • Spoiled or contaminated food is bad for health. By use preserve food we maintain own good health.
  • Food preservation help to inactivate the certain enzyme.
  • Air tight container storing help to prevent micro-organism, insects , bacteria etc.

The above point are helpful when we think about the principle of food preservation

Method of Food Preservation

The following 5 method are good for preservation of food:

1. Cold Storage:

You must have sometimes eaten mangoes and ladies finger in December – january and cauliflower in june. Though expensive in off season, these are available due to cold storage facilities. Food cam be kept for long periods of time in commercial cold storage room at proper humidity and very low temperature. Fruit and vegetables in cold storage are kept just above the point at which they freeze (31°- 35°F). While butter and meat may be kept at much lower temperature.

2. Freezing:

Most of foods stored by used of freezing. When the foods are frozen, the bacteria are unable to grow and the enzyme action is retarded or inactivated by blanching, prior to freezing. Before you decide to preserve food by freezing follow these steps;

  • Select the food with quality and maturity.
  • Blanch vegetables to inactivate enzyme.
  • Cool and pack foods in polythene bags, or proof wrapping foils, waxed paper or cellophane, etc.
  • Make small packs so that the entire package can be frozen quickly.

You must store these food at temperature below 0°F. In order to retain the flavour, texture and nutritive value use frozen food. If you allow the food for some time after thawing, micro-organism will mutilple and may spoil the food. After thawing, never refreeze the food as the spoilage of soft tissue may have set in.

3. Refrigeration:

This is most commonly used method of preserving food in a household. We can store meat, fish and poultry in the refrigerator for serval days. While milk products like curd and cheese can be stored for 2-3 days.

We can also store fruit and vegetables for the serval days in refrigerator. Without altering their texture, colour, flavour and nutrition value. In order to ensure their crispness, these must be stored in polythene bags.

4. Dehydration:

This is the process by which water is removed to increase the shelf life of the food. The principal of dehydration is that micro-organism are unable to grow in the absence of moisture. Few food have very little moisture e.g. grains and pulse. Some fruit, vegetables and immature legumes can preserved by this method. You must observed that dehydrated food are less in weight.

5. Radiation:

Radiation like gamma rays and ultraviolet rays have some use in the preservation of bread and cake products and packaging of bacon, meat and cheese in western countries. These radiation are mainly used to kill or reduce micro-organism in the air of processing room.

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