Back to: Food and Nutrition SS 2
Methods of Preservation
A number of food preservation techniques can be used which can either prevent, delay, or otherwise reduce food spoilage altogether. Preservatives can extend the shelf life of food and can last as long as it can be grown, stored, marketed, and kept in the home of the customer for a reasonable period of time.
Preserving or producing nutritional value, texture and flavour is an important aspect of food storage methods, although some methods have drastically altered the character of the preserved foods. These changes have now been seen in many cases as desirable qualities, such as cheese, yogurt, and pickled onions.
Any change that renders food unfit for human consumption is considered food spoilage. Contamination by microbes, insect infestation, or breakdown by endogenous enzymes is all possible causes of these alterations (those present naturally in the food). Food spoilage can also be accelerated by physical and chemical changes, such as the tearing of plant or animal tissues or the oxidation of certain food constituents. Foods derived from plants or animals deteriorate quickly once they are harvested or slaughtered. Any mechanical injury induced during postharvest processing may cause the enzymes stored in the cells of plant and animal tissues to be released. The cellular substance is broken down by these enzymes. Food quality is degraded as a result of the chemical processes catalysed by enzymes, such as the production of off-flavours, texture deterioration, and nutrient loss.
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.
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