**2. Ames test for bamboo charcoal and vinegars**

The preliminary safety evaluation, including cytotoxicity and mutagenicity, is performed in accordance with the Ames test [32], a widely used convenient and short-term assay with predictable accuracy for carcinogen up to 72–91% [35]. Referring to the Ames test, as proposed by Ames *et al*. [32], Waleh *et al*. [36], which indicates that if the sample is toxic for the strain, the bacterial count decreases, and the test result is likely to be misjudged. Therefore, the specimen cytotoxicity has to be tested before the mutagenicity test, in order to evaluate whether the growth of the strain is influenced. The mutagenicity can be implemented if there is no toxicity [32, 36]. In this report, the *S. typhimurium* TA98 and TA100 are used as test strains. TA98 is the strain sensitive to frame shifting mutation, as caused by specific mutagens; TA100 is the strain for testing base substitution variation [37].
