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The rumored “overnight” scares the nitrites in food.
Where does nitrite come from?
Plants like to absorb nitrogen-containing compounds from the environment into their bodies. The most common form is Nitrate, which is harmless. , but can be converted into nitrite under the action of enzymes, microorganisms, air and temperature.
Spinach overnight really beware!
The degree to which vegetables prefer to absorb nitrate from the environment:
leaf vegetables>root vegetables>onion and garlic>melons and fruits>beans>solanaceous fruits
On the part:
Stem root>leaf>fruit
To sum up, leaf vegetables are the highest risk of nitrite, followed by roots, fruits, solanaceous fruits and beans. [2]
Among them, Spinach is a common vegetable that is often mentioned as easily enriched in nitrates.
Experiments found that after spinach is cooked, even if it is refrigerated, it will contain nitrous acid after 16 hours. The salt content will also exceed the national standard, and it will be higher when placed at room temperature, so spinach is best eaten at one time, and do not leave it for too long.
According to “National Food Safety Standard – Limit of Contaminants in Food” (GB 2762-2017), the nitrite content in vegetable products should be less than 20mg/kg
[4-7]
References:
[1]https:https://www.efsa.europa.eu/en/corporate/pub/nitritesandnitrates170614
Food and Agriculture Organization World Health Organization. Evaluation of certain food additives. Fifty-ninth report of the Joint FAO/WHO Expert Committee on Food Additives. World Health Organ Tech Rep Ser. 2002;913 :i-viii, 1-153, back cover. PMID: 12677645.
[2] Salehzadeh H, Maleki A, Rezaee R, Shahmoradi B, Ponnet K. The nitrate content of fresh and cooked vegetables and their health-related risks. PLoS One. 2020;15( 1):e0227551. Published 2020 Jan 9. doi:10.1371/journal.pone.0227551
[3]https:https://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_172_01.html
[4] Liu Juan, Gao Yifen, Yang Qian, Shen Yonggen, Jiang Tao, Wang Weichen, Zhang Min, Lou Ge, Wang Wei. A preliminary study on the changes of nitrite content in leafy vegetables overnight[ J]. Food Research and Development, 2016, 37(02): 150-153.
[5] Wang Wanjuan. Analysis of changes in nitrite content in overnight dishes before and after cooking [J]. Food Safety Guide, 2020(36):119-120+122.DOI:10.16043/j .cnki.cfs.2020.36.075.
[6] Xiong Yan, Yin Zengsong, Ma Yanlan, Lin Kehui. The current situation and prevention measures of nitrate pollution in vegetables [J]. Journal of Yunnan Agricultural University, 2003(03):304-308. DOI: 10.16211/j.issn.1004-390x(n).2003.03.021.
[7] Jia Qi, Ye Xiulian, Yang Chenggen. Effects of different treatments on nitrite content in common leafy vegetables [J]. Journal of Jiangsu Agricultural University, 1997(02):95-97 .DOI:10.16872/j.cnki.1671-4652.1997.02.025.
[8]https:https://www.efsa.europa.eu/en/press/news/contam101209
[9] Li Haili. Research on nitrite control technology and storage properties of kimchi [D]. Hebei Agricultural University, 2012.
[10] Huang Runqiu, Chen Gong, He Yunchuan, Yan Zhengcai, Liang Yong, Zhang Qisheng, Li Jiayi, Wang Dongdong, Tang Yao. Effects of raw materials and processes on nitrite content in pickles [J]. Food and Fermentation Technology, 2020, 56(04): 1-5+49.
[11] Li Yiting, Yang Hongle, Sun Ning, Ban Litong, Huang Liang, Tong Yingkai. Effects of different soaking time on the content of tea polyphenols and nitrite in tea water[J]. Modern Food, 2020(02):174-177.DOI:10.16736/j.cnki.cn41-1434/ts.2020.02.059.
[12] Zhang Meijuan, Song Wenqing, Yang Xueyi, Huang Chuyan. Research on the content of nitrite in Qianbo water [J]. Curriculum Education Research, 2016(08):167-168.
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[13] Shen Qianqing, Zhang Guangming. Effects of repeated boiling of drinking water on water quality [J]. Environmental Science and Technology, 2011, 34(05): 128-130+134.
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[14] Hu Wenmin, Cai Zhanfan, Liang Shuxia. Nitrite content in “Thousand Boiling Water” and “Overnight Water”[J]. Modern Food, 2021(12):140-144+ 149.DOI:10.16736/j.cnki.cn41-1434/ts.2021.12.039.
[15] Amal AG. Changes in nitrate and nitrite contents of some vegetables during processing. Ann Agric Sci 2000;2:531-9
Editor: Xiaohui
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