Abstract: Nitrite content variation and nitrite formation mechanics of the vegetables, respectively stored in different room- temperatures, low temperatures and natural fermentations, are studied in this paper. And the test materials are varieties of Chinese cabbage, cabbage and white radish. The results show that the nitrite peaks appear in the initial stage (3days storge) in the three kinds of storage methods. The main reasons for nitrite peak formation of the varied treatments are different. When vegetables were plucked, their nitrate reductase activity increased. So the main reason for nitrite peak formation of vegetables stored in room-temperature and low temperature, is the reduction of nitrate into nitrite by vegetable’s nitrate reductase, where, nitite peak formation was caused by microorganisms in the course of fermentation. This peak value is much higher than that of the two other treatments in excesse of the ADI value established by FAO/WHO. But the nitrite content is in the safety edible range in the anaphasic stage (in the latter stage of storage 8 dags latter). The nitrite content value of the vegetables stored in room- temperature and low temperature is lower ADI value, so the vegetables are edibly safe.

Key words: nitrite, nitrate reductase, vegetable, store