Mutagenicity test suitable for marine natural seasonings containing free histidine

For the Ames test, mutagenic compounds must be separated from free histidine before quantitative determination of the mutagenicity of foods. This separation process may cause mutagenic compounds having similar chemical characteristics with histidine to be only partially recovered from the sample. We studied the recovery ratio of several mutagens before and after separation by forward mutation assay and the Ames test. In this report we reveal 1) the difficulty of quantitative analysis on the measurement of total mutagenicity by the Ames test, 2) the negligible influence of the presence of free histidine on the determination by the forward mutation test, and 3) better detecting sensitivity of Salmonella typhimurium TM677 on the sample at the same concentration.