What is the difference between fresh-keeping storage, cold storage, freezer and controlled atmosphere storage

What is the difference between fresh-keeping storage, cold storage, freezer and controlled atmosphere storage

1. Fresh-keeping warehouse

The storage temperature of the fresh-keeping warehouse is generally 0℃~5℃, which is mainly used to keep fresh, that is, to maintain the original quality and freshness of agricultural products for a long time, and the living products of agricultural products should not die as much as possible. In a dormant state, it reduces the loss of nutrients and maintains the quality of freshness. This is generally applied to fruits and vegetables. The current fruit and vegetable industry is planted intensively. In the process of transportation and sale, it is inevitable to use cold storage to maintain the nutrients that the fruits and vegetables should have.

　　 2. Cold storage

　　The temperature of the cold storage is generally -15℃～-18℃. Generally, the food is gradually put into the cold storage from time to time. After a period of time, the temperature of the cold storage reaches -18℃, and the pick-up is also irregular and irregular. There is no specific requirement for this “period", which is a typical cold storage. For example, meat and aquatic products have higher requirements for storage temperature to keep the internals from deteriorating. In addition, they should be removed and stored irregularly during the selling process. Generally, the cold storage in large supermarkets is a cold storage.

　　 3. Freezer

　　The temperature of the freezer low-temperature storage is generally -22～ -25. It uses various refrigeration equipment, namely artificial refrigeration, to keep the room at a certain low temperature. Many foods such as ice cream, seafood, etc. need to be stored at -25°C in order to not deteriorate. For example, if ice cream does not reach -25°C when stored, its fragrance will be lost; the umami taste and taste of seafood will be much worse. . The characteristics of the low-temperature storage are: the food is gradually put into the cold storage from time to time. After a period of time, the temperature of the cold storage reaches -25℃. There is no special cold storage design process and technical requirements for this period. The storage temperature of this cold storage is There are strict requirements, between -22℃～-25℃, this is a typical low temperature storage. Compared with the fresh-keeping warehouse, the frozen storage has a very different mechanism of action. Too low temperature will cause the death of food such as meat and seafood, and the freshness will be greatly affected. Therefore, for the storage of fruits, vegetables and meat, Not that the lower the temperature, the better.

　　4. Atmosphere storage

　　 Controlled atmosphere storage, also known as controlled atmosphere storage, is the most advanced method for fresh-keeping fruits and vegetables. It is based on the fresh-keeping warehouse, increasing the gas composition adjustment, and by controlling the temperature, humidity, carbon dioxide, oxygen concentration and ethylene concentration in the storage environment, it inhibits the respiration of fruits and vegetables, delays their metabolic processes, and better maintains the fruits and vegetables. Freshness and commerciality, prolong the storage period and fresh-keeping period (sale shelf life) of fruits and vegetables. Generally, controlled atmosphere storage can extend the storage period by 0.5-1 times than ordinary refrigeration; the fruits and vegetables stored in the controlled atmosphere warehouse will "wake up" from the "sleep" state after they are out of the warehouse. It can be extended 2~3 times of ordinary cold storage. Modified atmosphere storage can create the best environment for fruit and vegetable storage by changing the gas composition and relative humidity of the storage environment under suitable low temperature conditions. Its effects are manifested in the following aspects: Low oxygen created by controlled atmosphere storage (generally 3 %—5%), appropriate CO2 concentration can effectively inhibit respiration, reduce the loss of nutrients in fruits and vegetables, and at the same time inhibit the growth and reproduction of pathogenic bacteria, and control the occurrence of certain physiological diseases; remove ethylene in the storage environment to inhibit it It can accelerate the ripening of fruits and vegetables and delay the process of maturation and aging; increase the relative humidity in the ambient air to reduce the transpiration of fruits and vegetables, so as to achieve the purpose of long-term storage and preservation of fruits and vegetables