Microorganisms will not grow and will not deteriorate during the storage process of frozen vegetables. Compared with vegetables stored and transported at room temperature for a long time, it is safer.
After the fresh vegetables are picked, they will be pre-cooled to reduce the raw vegetable materials to about 0-10°C, and they are screened in a low-temperature environment and then cleaned, peeled, and sliced.
Afterward, according to different vegetable varieties, hot water, steam, microwave, high pressure, and other methods are used to kill microorganisms, and biological enzymes are inactivated, thereby prolonging the preservation time and flavor quality of vegetables. Finally, in the quick-freezing workshop at -30°C, the vegetables are rapidly cooled to -18～-20°C.
After this series of operations, the microorganisms, dirt, and pesticide residues on the vegetable surface have been effectively controlled.
Studies have shown that compared with vegetables that have been transported and stored at room temperature for a long time on the market, frozen vegetables have a slower nutrient loss and more stable taste and flavor.
Vegetables that have entered the quick-frozen state have slowed down the metabolic rate through low temperature, and some polyphenol antioxidants may also increase storage.
Therefore, as long as the quick-frozen vegetables are stored properly, the nutrition will hardly change much in the storage of up to several months or even ten months.