Food preservation methods

Mcooker: best recipes About kitchen and food

Food preservation methodsThe shelf life of food can be extended by preservation. The essence of conservation is to create unfavorable conditions for the activity of enzymes and the development of microorganisms. Methods of food preservation: physical, biochemical, chemical and physicochemical.

Physical way

The physical method includes canning with low and high temperatures.

Low temperature canning includes refrigeration and rapid freezing.

When cooled, the action of enzymes and the development of microorganisms slows down or stops. The products are cooled to 0-5 degrees, not allowing them to freeze. This canning method is used to store meat, fish, milk, dairy products, vegetables, fruits. Chilled products retain vitamins, flavoring, aromatic and other substances.

For long-term storage, food is quickly frozen at temperatures ranging from -18 to -25 degrees. Freezing is used for meat, fish semi-finished products and vegetables. But frozen foods are inferior to chilled ones in taste and nutritional properties.

High temperature preservation includes pasteurization and sterilization.

Food preservation methods
Photo by Admin

During pasteurization, products are heated to a temperature of 65 degrees for 30 minutes (long-term pasteurization) and to a temperature of 90 degrees for 60-90 seconds (short-term pasteurization). The shelf life of pasteurized products is not long, since only the microbes themselves die, and their spores remain. Jam, juices, milk, beer are pasteurized.

During sterilization, the products are hermetically sealed and heated to a temperature of 115-120 degrees for a certain time, as a result of which the microbes die. Sterilized food can be stored for a long time. But with this method, the nutritional value of products decreases, since part of the vitamins is destroyed, proteins are partially hydrolyzed and denatured, sugar and starch are partially broken down.

Biochemical method

This method of canning includes pickling and pickling.

These methods are based on the properties of acids to inhibit and inhibit the development of many microorganisms. When vegetables and fruits are fermented, lactic acid is formed. Acetic acid is used for pickling. In concentrations up to 1.8%, it completely inhibits the development of many microorganisms. At a concentration of up to 0.6%, acetic acid is used in combination with other preservation methods (storage at low temperatures, heat sterilization). Are pickled - fruits, vegetables, mushrooms.

Chemical method

The chemical method of preservation includes preservation with antiseptics.

When using antiseptics for preserving food, strict requirements are imposed on them: they must be used in very small doses, be completely harmless to humans, and do not impart unpleasant taste and odor to the food product.

Antibiotics can inhibit the growth of microorganisms, but their use is strictly limited. The antibiotic nisin is the most promising for canning food, since it is considered relatively harmless to humans. It is used in combination with heat sterilization.

Physicochemical method

This method includes drying and using sugar and salt.

Drying, as a method of canning, has been known since ancient times. This method does not require special devices, and the energy of the sun can be used. Moisture is necessary for the development of microorganisms.When moisture is removed, the concentration of substances in the cell sap increases, as a result of which microorganisms do not die, but no longer develop.

The method of using sugar and salt is based on creating conditions under which osmotic pressure is created in food products, which suppresses the development of microorganisms. When cooking jam, marmalade, jams, candied fruits, with the addition of concentrated sugar syrup and partial evaporation of water, unfavorable conditions for microorganisms are created. As a result, cells become dehydrated and microorganisms die. Reducing the amount of sugar creates favorable conditions for microorganisms, which leads to spoilage of the product.

The same effect on microorganisms is exerted by the addition of table salt to products up to 20%.

Natalia Victorovna


Soup in culinary history   Basil use

All recipes

New recipe

© Mcooker: best recipes.

map of site

We advise you to read:

Selection and operation of bread makers