Low temperature storage is a common method to store cooked food. Its main principle is to effectively inhibit the growth and reproduction of microorganisms, reduce the activity of enzymes, weaken the chemical reaction in food, and better maintain the original flavor and nutritional value of food. Low temperature storage can be divided into refrigeration method and freezing method according to its temperature, and the refrigeration temperature is above freezing point.
Frozen foods mainly include vegetables, fresh meat, fresh fish, fruits, dairy products, cooked products and semi-finished products. Freezing method is to freeze food in an environment below freezing point, which is suitable for storing animal food. Freezing can preserve food for a long time without spoilage. However, after long-term storage, although the quality of food has not changed much, its moisture content has decreased, its back-nourishing value has decreased and its taste has deteriorated. In addition, when more than two kinds of food are stored in the same freezer, they should be sealed and isolated with non-toxic food bags. Prevent odors from polluting each other. At the same time, it can also reduce the loss of water in food.
2, high temperature storage method
High temperature storage is a common method of food storage in catering industry. Because microorganisms have weak tolerance to high temperature, they can effectively kill microorganisms and destroy the activity of enzymes when the temperature rises, which can prevent the influence of microorganisms on food and achieve the purpose of storing food. The method is to cook or steam the food thoroughly (reaching the high temperature above 100 degrees), take it out or soak it in the original soup, and put it in a cool and ventilated place without stirring to prevent the food from being polluted again. This method can keep food from spoiling for a long time. This method is suitable for the preservation of finished and semi-finished products of animal foods, and also for the preservation of dry foods such as water.
3. Ventilation storage method
Ventilation storage method is mainly suitable for preserving grain, dry grain and food that needs air drying. Their characteristic is that they are afraid of mildew and covering. For example, rice, flour, peanuts, vegetables and other foods need ventilation during storage, which can make mold difficult to grow, maintain the original ingredients of food and reduce mildew.
4, pickling, pickling, sauce, bubble storage method
This method is generally to add salt, sugar, vinegar, sauce and spiced food in a certain proportion to make the food absorb to a certain concentration. Inhibit the growth of microorganisms and achieve the purpose of long-term preservation of food. For example, pickled products include salted radish strips, salted beans, sweet and sour garlic and so on. Pickled products include spiced kohlrabi, pickled cucumber and pickled cabbage. Pickled products include pickled cabbage, pickled pepper and pickled eggplant.
The nutritional value of food generally treated by salting, pickling, dipping and dipping. Will be reduced, because some vitamins and inorganic salts in food are destroyed and lost, especially the fibrous muscles of animal food will become hard and difficult to be absorbed and digested by the human body. However, after processing and cooking, the flavor is rich and the taste is excellent. This method of storing food is simple and easy, and it is widely used in catering industry.
5. Smoked storage method
Smoking is a method of smoking and baking food with smoke produced by incomplete combustion of sawn, loose branches and other materials. Smoked food not only reduces the moisture inside the food, but also has the function of sterilization and preservation, and wood tar and creosote oil adhere to the surface of the food, which can prevent the growth of bacteria and thus achieve the function of antiseptic storage. The common smoked products are smoked fish, smoked chicken and bacon.
6, vacuum sealing preservation method
Vacuum sealing preservation method is a method to keep food in a vacuum state without contact with microorganisms in the air, such as canned products and vacuum packaging products. This method is suitable for the preservation of various foods. With the continuous development of science and technology, there are more and more ways to store food, such as nuclear radiation storage method and modified atmosphere method. Their main principle is to control or kill microorganisms growing in food, delay the metabolism of internal tissues of raw materials, thus prolonging the storage time of food, improving the storage quality and achieving the purpose of preservation.