The differences between cold storage, refrigerated storage, low-temperature storage, quick-freezing storage, and controlled atmosphere storage.

Fresh-keeping warehouses maintain a temperature of +2℃ to +5℃ and are used for preserving fruits, vegetables, dairy products, fresh eggs, and fresh meat. The temperature is kept low, but generally not below 0℃.

Low-temperature food storage does not mean the lower the temperature, the better, nor does it guarantee good storage results for all foods at any low temperature. Storage in fresh-keeping warehouses generally does not affect the internal structure of food; preservation helps maintain the original flavor and freshness. However, customers should not pursue excessively low storage temperatures, as lower temperatures will directly increase initial equipment investment and operating costs.

Refrigerated warehouses maintain a temperature of -18℃. Food is typically placed into refrigerated warehouses gradually and periodically until the temperature reaches -18℃. Retrieval is also irregular and unpredictable. There is no specific requirement for this “period,” which is typical of refrigerated warehouses.

For example: A factory canteen or a food raw material cold storage facility purchases 500 kg of meat today and places it in the cold storage. After a period of time, the temperature in the cold storage reaches -18℃. They don’t have specific requirements for this period; this is a characteristic of a refrigerated cold storage facility. Depending on the canteen’s needs, 100 kg of meat may be taken out today, 50 kg tomorrow, and 200 kg the day after. This is a typical example of a refrigerated cold storage facility.

Low-temperature storage facilities operate at temperatures below -25℃. This is because some foods, such as ice cream and seafood, need to be stored at -25℃ to prevent spoilage. If ice cream isn’t stored at -25℃, it will lose its aroma; seafood will have significantly less freshness and texture. The characteristic of low-temperature storage is that food is gradually placed into the cold storage at irregular intervals, and after a period of time, the temperature reaches -25℃. There are no specific requirements for this period, but the temperature of the cold storage facility itself is strictly controlled, ranging from -18℃ to -25℃. This is a typical example of a low-temperature storage facility.

Controlled atmosphere storage (CAS) is a modern facility developed from cold storage (high-temperature storage) for storing fruits, vegetables, flowers, grains, and other agricultural products. Besides controlling the internal temperature, CAS effectively regulates atmospheric parameters to extend storage life and improve storage quality. The term “controlled atmosphere storage” was initially used by the British as “refrigerated gas storage,” highlighting the similarity between the two. Later, American scholars suggested changing the name to “controlled atmosphere storage,” which has been widely adopted.

Blast freezing refers to rapidly cooling goods to a very short time, causing significant changes in their internal quality to achieve preservation and quality maintenance. This requires a continuous deep-freezing system to achieve the final goal of quick freezing. Specifically, the shorter the process by which food passes through the -2°C ice crystal zone in the deep-freezing system, the higher the freshness of the food.