On the Histamine Content in Miso

Several amines have been found in some kinds of Miso in the course of this series of study. Therefore, 147 samples of homemade Miso were collected from farm households in Saitama, Tochigi and Gunma prefectures and analyzed for histamine in order to get more detailed information about their qualities. All the samples were treated with acidic alcohol. Histamine in the extracts was detected qualitatively by paper chromatography and after purification, identified in the form of its picrate, by the melting point determination method with authentic substances. Quantitative determinations of histamine in the extracts were made by paper chromatographical and photometrical procedures. The results are as follows. The histamine content in the sampled Miso was in a range of zero to 28 mg% and approximately 6 % of the total samples were found to contain histamine in an amount higher than 20 mg%. However, there existed no significant correlation between the histamine content and other individual factors such as duration of aging and compositions of ingredients including sodium chloride.