The content of nitrite in pickled products was the highest on the 4th to 8th day, and began to decrease after the 9th day, and basically disappeared after the 20th day, so the pickled products could be eaten after one month.

If the curing time is less than one month, the content of nitrite will be high.

Vegetables themselves contain nitrate, which is gradually reduced to nitrite by (bacteria, etc.). ) in the curing process, nitrite is the precursor of nitrosamine, a carcinogen.

Extended data:

In the process of food curing, whether wet curing or dry curing is adopted, the curing agent forms a solution and diffuses into food tissues, which reduces the water activity and increases the osmotic pressure, thus inhibiting the activities of microorganisms and enzymes. Therefore, the diffusion and penetration of solution is the theoretical basis of pickled food processing.

Diffusion and permeation of solution:

The speed of food curing depends on osmotic pressure, which is directly proportional to temperature and concentration. Therefore, in order to speed up the pickling process, it should be carried out in high temperature and high concentration solution as much as possible. As far as temperature is concerned, the osmotic pressure will increase by 0.3% ~ 0.35% for every increase of 65438 0℃.

In the process of food curing, the concentration of internal and external solutions of food gradually tends to balance through osmosis, and the concentration of external solutions of food and internal solutions of food reaches balance through solute diffusion. Therefore, the pickling process is actually a combination of diffusion and infiltration.