Influenced by traditional customs, people in our country are accustomed to eating various pickled vegetables, such as Northeast China's suan cai (sour cabbage), southern China's pao cai (pickled vegetables), and various types of preserved vegetables, salted vegetables, and cold salads. Pickled vegetables serve the purpose of preserving vegetables and play a good buffering role in times of vegetable shortages. However, in recent years, the issue of "nitrite" in pickled vegetables has received increasing attention. So, can you actually eat "pickled vegetables"?
We advocate eating fresh vegetables whenever possible, but scientifically pickled vegetables are not off the table.
Vegetables themselves contain nitrates, which are gradually reduced by bacteria during the pickling process to form nitrites. Nitrites are precursors to N-nitroso compounds, which are carcinogens. Numerous studies both in China and abroad have shown a pattern in the changes of nitrite levels during pickling: as the pickling time increases, the amount of nitrite produced gradually increases, but after reaching a peak, it gradually decreases as the pickling time continues. Therefore, when consuming pickled vegetables, it is important to avoid the nitrite peak.
Traditional sauerkraut and pao cai are highly nutritious fermented vegetables. Good anaerobic fermentation processes do not produce harmful levels of nitrites. In pao cai and sauerkraut that have been inoculated with lactic acid bacteria and undergone thorough lactic acid fermentation, nitrites are broken down under acidic conditions and are also enzymatically degraded by nitrite reductase produced by some lactic acid bacteria. This means that a large amount of nitrite is decomposed during the pickling process, making the product both nutritious and relatively safe. Therefore, thoroughly fermented sauerkraut and pao cai are safe to eat, while incompletely fermented pickled vegetables should be avoided as much as possible.