Chinese cabbage must be marinated for at least 15 days before it is safe to eat.

In the first week of pickled cabbage, the nitrite content remained at a low level without a significant increase; then the nitrite content increased sharply, reaching a peak on the 11th day; after 11 days, the nitrite content increased sharply. decline, and after about 2 weeks the content is reduced to the low level before pickling.

The nitrite content is closely related to the color change

In the process of pickling cabbage, it can be found that the color of the pickled vegetables changes from green to yellow in the early stage because of the increased nitrite content. Process; in the later stage, after all the pickles turn yellow, the yellow color changes from light to dark, which is the process of reducing the nitrite content back to a lower level. Therefore, in the process of making homemade pickles, ordinary citizens can judge the nitrite content by observing the color changes of the pickles, so as to avoid eating unpickled pickles (with high nitrite content).

Nitrate and nitrite are widely present in the human environment and are the most common nitrogen-containing compounds in nature. Nitrate in the human body can be reduced to nitrite under the action of microorganisms.