2. Cold water pre-cooling
Cold water pre-cooling is a cooling method that uses water as a medium. The fruits and vegetables are immersed in cold water or rinsed with cold water to achieve the purpose of cooling. There are two types of cooling water: low temperature water (usually around 0～3℃) and tap water. The former has a good cooling effect and the latter has low production costs. The water cooling methods currently in use are flow water system and conveyor belt system. The cooling rate of water is fast, and the product loses less water, but it is necessary to prevent the pollution of fruits and vegetables by the cooling water. Therefore, some antiseptic agents should be added to the cooling water to reduce the cross-infection of pathogenic microorganisms. Commercially suitable fruits and vegetables for water cooling include citrus, carrots, celery, sweet corn, netted melon, kidney beans, etc.
Pre-cooling with cold water is only suitable for firm fruits, but not good for vegetables. Similarly, cold water pre-cooling only has the effect of cooling down, and has no functions such as sterilization and preventing plant aging. But water is the key reason for nourishing bacteria, so ZKGY believes that fruits and vegetables that have been pre-cooled with water are not suitable for long-term storage.