Storage preservation, or fresh-keeping storage, primarily focuses on preservation. This means maintaining the original quality and freshness of agricultural products over an extended period. Even after being stored for some time, fresh agricultural products should remain in a state and quality similar to when they were first harvested.

The Relationship Between Temperature and the Preservation of Agricultural Products:
After being harvested, agricultural products are fresh and highly nutritious for a short period. During storage, they sustain their life processes by continuously consuming their stored nutrients, gradually losing their nutritional value and fresh quality. Additionally, pests can feed on the stored nutrients of agricultural products, leading to spoilage, loss of freshness, and edibility. Temperature is a critical factor in preserving the nutrition and quality of agricultural products after harvest. Generally, lower temperatures result in fewer nutrient losses, reduced pest damage, and a longer retention of freshness. Moreover, smaller fluctuations in temperature lead to better preservation outcomes. However, preservation temperature should not be excessively low, as overly low temperatures can cause freezing damage. Therefore, preservation storage requires a relatively stable and suitable low-temperature environment.

Maintaining the Temperature for Preserving Agricultural Products:
Ambient temperatures change with seasons and time of day. During the conventional harvest season for most agricultural products, temperatures are relatively high, with significant daily variations, making them unsuitable for preservation storage. Many simple methods involve storing agricultural products in naturally cool and stable environments, such as caves, cellars, or shaded areas, to extend their freshness. However, these methods do not allow for precise temperature control, resulting in poor preservation outcomes and shorter freshness periods. To achieve long-term preservation storage at the required temperatures, the solution lies in artificially creating a relatively stable low-temperature environment. This is achieved through mechanical equipment and electronic instruments that enable precise temperature control within a certain range. Various types of cold storage facilities are designed for this purpose. The optimal preservation temperature for most agricultural products is around 0°C.