Recently, news about a man who ate pickled products three times a day and was diagnosed with late-stage gastric cancer has been trending. Will long-term consumption of pickled vegetables harm your health? How to eat pickled vegetables more safely? With these questions, the reporter interviewed Yu Huanling, professor and deputy dean of the Department of Nutrition and Food Hygiene, School of Public Health, Capital Medical University.
Can you eat pickled vegetables?
“Pickled vegetables are traditional foods obtained by pickling or pickling other vegetables, including common pickles, kimchi, fermented sauerkraut, etc.” Yu Huanling introduced that some media reports mentioned the impact of pickled vegetables on health, mainly reflecting On the issue of nitrite content in pickled vegetables.
Yu Huanling said that excessive intake of nitrite can induce toxic methemoglobinemia, causing symptoms such as chest tightness, difficulty breathing, dizziness, headache, shortness of breath, nausea, vomiting and diarrhea. Severe cases may cause coma, convulsions, incontinence of urine and feces, and even death due to respiratory failure.
“In addition, nitrite can also react with amines, the breakdown products of protein in the stomach, to generate N-nitroso compounds such as nitrosamines, which are extremely teratogenic and carcinogenic.” Yu Huanling said.
According to the national food safety standard GB 2762-2012 “Limits of Pollutants in Food”, the nitrite (calculated as sodium nitrite) content in pickled vegetables shall not exceed 20mg/kg, and the agricultural industry standard NY/T 437-2012 “Green Food” Pickles” stipulates that the nitrite content in green food pickles should not exceed 4mg/kg.
So, are the pickled vegetables that people usually eat safe? Yu Huanling said that the nitrite content in pickled vegetables will continue to decrease with time, and the peak value often appears 5-10 days after pickling, mostly at 20-30 mg/kg. Usually, after 20 days, the content of nitrite in pickled vegetables will continue to decrease. The nitrite content is relatively low. “If you pickle your own kimchi, it is best to eat it within 2 days or 20 days later.”
“Pickled vegetables are relatively safe if you pay attention to hygiene and operate them properly. The most important thing to prevent nitrite poisoning is to avoid misuse, that is, using nitrite as table salt.” Yu Huanling said.
How to eat more safely?
Yu Huanling said that traditional pickled vegetables are fermented using the high osmotic pressure of salts and the action of microorganisms. However, because the fresh vegetables used as raw materials for pickled dishes are usually highly enriched in nitrates, during traditional storage, fermentation and other processes , Nitrate is easily converted into nitrite by nitrate reductase bacteria, causing safety problems such as nitrite residue and excessive levels.
“In life, although food poisoning due to the nitrite content in pickled vegetables is relatively rare, for the sake of everyone’s health, the nitrite content can be reduced as much as possible by improving the process.” Yu Huanling suggested that vegetables can be The raw materials are hot blanched and stored at low temperature, and an appropriate amount of tea polyphenols, ginger juice, spices, etc. are added to the fermentation broth to reduce the production of nitrite.
According to the national food safety standard GB 2760-2014 “Standards for the Use of Food Additives”, antioxidants allowed to be added to pickles include phytic acid, ascorbic acid, phospholipids, D-erythorbic acid and its sodium salt, etc. “The addition of antioxidant vitamins can inhibit the production of nitrite in kimchi, and the effect of ascorbic acid (vitamin C) is better than vitamin E and vitamins, suggesting that some multivitamins can be appropriately used when pickling.” Yu Huanling said.
“Compared with fresh vegetables, the nutrient content of most pickled vegetables is reduced, and the content of salt and nitrite is increased. Therefore, although pickled vegetables are delicious, attention should be paid to controlling the consumption to avoid excessive sodium intake.” Yu Huanling explain.
Yu Huanling recommends eating pickled vegetables with vegetables and fruits rich in vitamin C, such as bell peppers, broccoli, winter dates, strawberries, etc., which can not only improve food safety, but also reduce the harm of nitrite to the body.