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Mutagenicity of nitrite-treated soy sauce in Chinese hamster V79 cells
S Kimura1, K Okazaki, M Higashimoto
1Department of Microbiology, Kochi Medical School, Japan.
Abstract:
Mutagenicity of 4 kinds of Japanese soy sauce and tyramine, which is a precursor of a mutagen (3-diazotyramine) and present in soy sauce, after nitrite treatment under a yellow lamp was studied in Chinese hamster V79 cells with 6-thioguanine (TG) as a selective marker. The frequencies of mutation caused by nitrite-treated samples of soy sauce increased in the V79 cells in a dose-dependent manner. Four kinds of nitrite-treated soy sauce induced 139 to 473 TG-resistant mutants per 10(5) clonable cells per milliliter of soy sauce equivalent in the cells. Nitrite-treated tyramine was also mutagenic for the cells; it induced 8.6, 13.3, and 18.3 TG-resistant mutants per 10(5) clonable cells at concentrations of 20 micrograms, 56 micrograms, and 112 micrograms, respectively.
Insights
Nitrite treatment of Japanese soy sauce and tyramine, a precursor, created mutagens. These mutagens increased mutations in Chinese hamster V79 cells in a dose-dependent manner, indicating soy sauce mutagenicity.
Area of Science:
- Toxicology
- Food Chemistry
- Genetics
Background:
- Soy sauce contains tyramine, a precursor to the mutagen 3-diazotyramine.
- Nitrite treatment can convert tyramine into mutagenic compounds.
- Understanding the mutagenicity of treated soy sauce is crucial for food safety.
Purpose of the Study:
- To investigate the mutagenicity of four Japanese soy sauce varieties after nitrite treatment.
- To assess the mutagenic potential of tyramine following nitrite exposure.
- To quantify the dose-dependent mutagenic effects in a cellular model.
Main Methods:
- Chinese hamster V79 cells were used as the test system.
- 6-thioguanine (TG) served as the selective marker for mutations.
- Cells were exposed to nitrite-treated soy sauce samples and tyramine under controlled conditions (yellow lamp).
Main Results:
- Nitrite-treated soy sauce significantly increased mutation frequencies in V79 cells.
- Mutagenic effects of soy sauce were dose-dependent, ranging from 139 to 473 TG-resistant mutants per 10(5) cells/mL.
- Nitrite-treated tyramine also exhibited mutagenicity, inducing dose-dependent increases in TG-resistant mutants.
Conclusions:
- Nitrite treatment of Japanese soy sauce generates mutagenic compounds.
- Tyramine in soy sauce contributes to its mutagenicity after nitrite exposure.
- The study highlights the potential genotoxic risk associated with nitrite-preserved soy products.