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Occurrence of nitroso compounds in fungi-contaminated foods: a review
Abstract:
Dimethylnitrosamine (NDMA), diethylnitrosamine (NDEA), methylbenzylnitrosamine, and a new N-nitroso compound, N-3-methylbutyl-N-1-methylacetonylnitrosamine (NMAMBA), were found in cornbread that was inoculated with Fusarium moniliforme and underwent an incubation and the addition of a small amount of NaNO2. The carcinogenicity of NMAMBA was shown by the induction of forestomach carcinomas and liver tumors in mice and rats. Another new nitrosamine, N-2-methylpropyl-N-methylacetonyl nitrosamine, was isolated in millet and wheat flour after similar treatment. Some species of fungi not only can reduce nitrates to nitrites but also can increase the amount of secondary amines in the moldy foods and provide favorable conditions for the synthesis of nitrosamines. Some fungi may utilize primary amines to synthesize nitrosamines in appropriate culture mediums. Furthermore, the cornmeal may naturally contain trace amounts of nitrosamines, as detected by a gas chromatography/thermoenergy analyzer. Prolonged feeding of F. moniliforme-inoculated cornbread alone also induced the development of forestomach carcinoma in rats. This indicates the occurrence of potential carcinogens, perhaps certain Fusarium mycotoxins, in the moldy cornbread in addition to the carcinogenic nitrosamines. Another nitroso compound, Roussin red methylester (di-mu-methanethiolatotetranitrosodiiron) was found in pickled vegetables that are eaten daily in the Linxian (China) area. Roussin Red may provide NO-2 ions, which would react readily with secondary amines to form nitrosamines. Possibly this compound is a natural tumor promoter and is able to induce epithelial hyperplasia of the upper digestive tract and forestomach papilloma in treated mice. Also, trace amounts of NDMA, NDEA, and some other nitrosamines were found in the extract of pickled vegetables.
Insights
Moldy foods like cornbread and pickled vegetables can contain carcinogenic nitrosamines and mycotoxins. Fusarium fungi contribute to nitrosamine formation, posing health risks from contaminated food products.
Area of Science:
- Food Science
- Toxicology
- Mycology
Background:
- Certain fungi, including Fusarium moniliforme, can produce toxic compounds.
- Nitrosamines are a class of chemicals known for their carcinogenic properties.
- Traditional food processing and storage can lead to the formation of harmful substances.
Purpose of the Study:
- To identify and characterize new nitrosamines in mold-contaminated food.
- To investigate the carcinogenic potential of novel N-nitroso compounds.
- To explore the role of fungi in nitrosamine synthesis in food.
Main Methods:
- Inoculation of cornbread with Fusarium moniliforme and incubation with sodium nitrite.
- Isolation and identification of N-nitroso compounds using gas chromatography/thermoenergy analyzer.
- Carcinogenicity studies in mice and rats fed with contaminated food and isolated compounds.
Main Results:
- N-3-methylbutyl-N-1-methylacetonylnitrosamine (NMAMBA) and another new nitrosamine were identified in treated cornbread, millet, and wheat flour.
- NMAMBA induced forestomach carcinomas and liver tumors in rodents.
- Fusarium species demonstrated the ability to synthesize nitrosamines from amines and nitrites.
- Prolonged feeding of F. moniliforme-inoculated cornbread induced forestomach tumors, suggesting the presence of other carcinogens.
- Roussin red methylester was found in pickled vegetables, potentially promoting nitrosamine formation and tumor development.
Conclusions:
- Moldy foods can be a significant source of carcinogenic nitrosamines and potentially other mycotoxins.
- Fungi play a crucial role in the endogenous synthesis of nitrosamines in food.
- Novel nitrosamines like NMAMBA exhibit potent carcinogenicity.
- Consumption of contaminated foods poses a risk for upper digestive tract and liver cancers.