N-nitrosamines in Chinese foods

Song, Pu; Hu, Jia

doi:10.1016/0278-6915(88)90120-2

Cited by 39 publications

(11 citation statements)

References 11 publications

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“…Volatile N‐ nitrosamines can be extracted from foods with solvents or by distillation and determined by gas chromatography/mass spectroscopy (GC‐MS). Distillation can be based on vacuum (Sen & Seaman, 1981; Song & Hu, 1988; Sen et al , 1996), steam (Sen et al , 1997), or mineral oil (Greenfield et al , 1982a, b) techniques. In each case the distillate is collected in a trap or a succession of traps cooled with ice, dry ice, or liquid nitrogen and the N ‐nitrosamines are extracted into a low‐boiling solvent, invariably dichloromethane (DCM).…”

Section: Methodsmentioning

confidence: 99%

The determination of N-nitrosamines in food

Crews

2010

Quality Assurance and Safety of Crops &Amp; Foods

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Introduction N‐nitrosamines are formed in food as a result of natural chemical interactions, but mainly through food processing activity. Most are potent carcinogens and their determination is therefore of considerable importance. They exist in various chemical forms and have been measured by colorimetric and spectroscopic methods following gas or liquid chromatography or as a total N‐nitroso group by measurement of chemically released nitric oxide. Objectives To provide an overview of the available methods for the analysis of N‐nitrosamines in food that includes recently developments. Methods The literature was reviewed from the discovery of the N‐nitrosamine problem and the introduction on the N‐nitroso‐specific detector. Results The evaluation shows that analytical detection methods for volatile N‐nitrosamines in food have changed little since the introduction on the N‐nitroso‐specific detector and that research into the occurrence and formation of both non‐volatile N‐nitrosamines and the apparent total N‐nitroso content (ATNC) have declined. Methods for measuring the apparent total N‐nitroso content have not been improved significantly in recent years. Conclusion Modern sample extraction techniques and mass spectrometric methods for the volatile N‐nitrosamines have been applied more extensively to water analysis and offer a good opportunity to improve the determination of these carcinogens in food and make the analysis more widely available. Developments in liquid chromatography‐mass spectrometry should provide an avenue for renewed interest in non‐volatile N‐nitrosamines, and could help with the identification of novel compounds whose presence is suggested by the high apparent total N‐nitroso content of some foods.

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Section: Methodsmentioning

confidence: 99%

The determination of N-nitrosamines in food

Crews

2010

Quality Assurance and Safety of Crops &Amp; Foods

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“…Numerous studies have measured levels of volatile nitrosamines in preserved and fermented foods (Zou et al, 1994; Poirier et al, 1987; Gao et al, 1991; Siddiqi et al, 1988; Fong and Chan, 1977). One comprehensive survey of nitrosamine levels in Chinese foods (Song and Hu, 1988) included measurements of cured meats, other meats, seafood, soy sauce, fermented bean curd, pickled and salted vegetables and other miscellaneous foods. For each type of food on the questionnaire, we used the median of published values (or the mean if that was the only value reported) to categorize by the level of nitrosamines.…”

Section: Methodsmentioning

confidence: 99%

Dietary exposure to nitrite and nitrosamines and risk of nasopharyngeal carcinoma in Taiwan

et al. 2000

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Previous studies of nasopharyngeal carcinoma (NPC) have found elevated risks with higher consumption of salted fish and preserved foods, particularly during childhood. These foods can contain high levels of nitrosamines; however, most studies have not estimated exposure to nitrosamines directly. We conducted a case‐control study in Taiwan to evaluate dietary intakes and NPC risk. A total of 375 cases (99% response rate) and 327 controls (88% response rate) were interviewed about their diet as an adult and at age 10 using a food‐frequency questionnaire. We interviewed mothers of participants about their child's diet at age 10, age 3 and during weaning and the mother's diet while she was breast‐feeding. Mothers of 96 cases and 120 controls were interviewed. Nitrosamine and nitrite levels were assigned to 66 foods based on published values. Intake of nitrosamines and nitrite as an adult was not associated with risk of NPC. High intakes of nitrosamines and nitrite during childhood and weaning were associated with increased risks of NPC for foods other than soy products. Adjusted odds ratios for the highest quartile were 2.2 [95% confidence interval (CI) 0.8–5.6] for age 10, 2.6 (95% CI 1.0–7.0) for age 3 and 3.9 (95% CI 1.4–10.4) for weaning diet. Intakes of nitrite and nitrosamines from soybean products during childhood and weaning were inversely associated with risk. Soybeans contain known inhibitors of nitrosation, and thus may explain the inverse association we observed. Our results suggest that nitrosamine and nitrite intake during childhood may play a role in the development of NPC. Int. J. Cancer 86:603–609, 2000. Published 2000 Wiley‐Liss, Inc.

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“…It is well known that N -nitrosamines are a class of undesired industrial and environmental pollutants, many of which are carcinogenic, mutagenic, and teratogenic. − In particular, N -nitrosodimethylamine (NDMA), which is the simplest dialkylnitrosamine, has been demonstrated to be a potent carcinogen to various organs in animals, including liver, lung, and kidney. − As reported, NDMA has been found in air, soil, water, food, cosmetics, rubber products, and many other materials. − Therefore, the U.S. Environmental Protection Agency (U.S. EPA) defined NDMA as a probable human carcinogen…”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigation of N-Nitrosodimethylamine Formation from Nitrosation of Trimethylamine

2009

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Tertiary amines have been demonstrated to be capable of undergoing nitrosative cleavage to produce carcinogenic N-nitrosamines. The reaction mechanism of the nitrosation of trimethylamine (TMA) to produce N-nitrosodimethylamine (NDMA) was investigated at the CBS-QB3 level of theory. The formation of NDMA from TMA was proposed to be initiated by the formation of an iminium ion, Me(2)N(+) horizontal lineCH(2). Two different mechanisms (NOH elimination mechanism and oxidation abstraction mechanism) leading to Me(2)N(+) horizontal lineCH(2) were investigated, and the oxidation abstraction mechanism was found to be mainly operative. This result indicates that the oxidation abstraction mechanism plays an important role in the nitrosation of both N,N-dialkyl aromatic and tertiary aliphatic amines. Starting from the iminium ion, two experimentally proposed mechanisms (pathways 1 and 2) and one new mechanism (pathway 3) were examined. Pathway 1 proposes that the iminium ion undergoes hydrolysis to give dimethylamine (DMA), which then can be further nitrosated to NDMA; pathway 2 proposes that the iminium ion reacts with NO(2)(-) and forms a neutral intermediate, which then collapses to NDMA. In pathway 3, the iminium ion reacts with N(2)O(3) to give NDMA. Calculation results indicate that in aqueous solution pathway 1 is more feasible than pathways 2 and 3; moreover, the transformation from the iminium ion to NDMA is the rate-determining step. This work will be helpful to elucidate the formation mechanisms of the carcinogenic N-nitrosamines from the nitrosation of tertiary amines.

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N-nitrosamines in Chinese foods

Cited by 39 publications

References 11 publications

The determination of N-nitrosamines in food

The determination of N-nitrosamines in food

Dietary exposure to nitrite and nitrosamines and risk of nasopharyngeal carcinoma in Taiwan

Theoretical Investigation of N-Nitrosodimethylamine Formation from Nitrosation of Trimethylamine

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