Food Preservation is a set of procedures and resources for preparing and packaging food products in order to store and consume them long afterwards.
The substances that make up food change rather quickly. This alteration is caused by microbes that use their nutritional elements for their development, which causes their decomposition. The alteration of food is also due to the action of enzymes, chemical compounds that accelerate the speed of reactions.
The main objective of food preservation is to prevent or delay the damage caused by microbes, and therefore, their harmful effect on food. For this, it is necessary to apply an adequate treatment; the foods subjected to this treatment are called canned food.
Below are the conservation techniques most used today:
• Freezing: it consists in subjecting the food to temperatures between 0ºC and -4ºC, in order to eliminate the heat; This method makes it possible to temporarily stop the growth of microorganisms and slows down the rate at which enzymes act.
• Refrigeration: characterized by storing food at a temperature of 5 ºC or less; It is used to keep food fresh, and to preserve it for some time.
• Drying or dehydration:It can be natural or artificial. With this method, microorganisms do not develop nor do enzymes exert their action in dry foods. In natural drying the Sun intervenes, it can be used in fruits (raisins), grains, legumes. Today they can be dried using ovens, tunnels or driers.
• Salting and smoking: by adding salt to the food, it gives up its water, and the bacterial and enzymatic activity slows down. When food is subjected to wood smoke (beech, oak, birch), a series of chemical substances with great sterilizing power are originated and that, in addition, give a typical aroma and flavor to the food.
• Canning: consists of sterilizing the food and the container. The containers can be made of glass, tin, aluminum and cardboard. Before being packaged, the food is cooked and cleaned, cooking uses different temperatures and times depending on whether it is meat, fish or fruit.
• Pickle:It is used in cabbage, cucumber, cauliflower, grains, olives, etc. The edibles are salted and then preserved in vinegar, with or without spices. This technique includes curing, it includes smoking, salting and marinade in brine or vinegar, the first two are used in red meat.
• Sugar concentrate: consists of adding sugar to fruit and / or plant preparations, high concentrations prevent the proliferation of microorganisms except for some fungi, to stop their growth, oxygen is removed from the containers by covering the surface with paraffin or vacuum sealed containers.
• Chemical additives:they are non-nutritive substances intentionally added to food in small amounts, to improve appearance, taste, consistency or keeping properties. The most used for food preservation are sodium benzoate, acetic acid, sodium citrate, sulfur and sodium nitrite.
• Other modern methods: some radiations, such as X-rays, ultraviolet light, etc., are forms of energy that affect living matter, and seriously affect it, leaving food free of microorganisms, and being preserved for long periods.
