Pickled vegetables contain nitrite, which is indeed a carcinogen, but it takes a long time and a lot to cause cancer. Nitrate contained in vegetables during curing is transformed into nitrite by nitrate reductase in bacteria. However, the nitrite content of pickled vegetables only peaks in 3-8 days, and then gradually decreases, and the nitrite content will be very small after 20 days.
Extended data:
Pickled kimchi is a delicious dish. Pickling is to let a lot of salt penetrate into food tissues to achieve the purpose of preserving food. These pickled foods are called pickled products. Pickled products include pickles, bacon, salted eggs, pickled cucumbers, pickled radishes and so on.
References:
Baidu encyclopedia-pickles