A radiation and various chemical mutagens exist in our environmental life. Since many of these chemicals show carcinogenicity, the influence on human health and the environment are attached importance. The genotoxicity test using a lot of microorganism was developed, and it has been come to be able to detect potential mutagens and carcinogens promptly and handily now. An umu test was developed in 1982 as a rapid genotoxicity assay that had used a Salmonella typhimurium TA1535/pSK1002 strain. This test has been employed Japan and many foreign countries up to now as the method, in which utility is high as the screening methods such as an environmental sample, foods, medicines, and anti-genotoxic methods. In Japan, it has already been adopted as an official method for water and wastewater test methods in 1993 and 1997, respectively. It is also employed as German standard methods (DIN 38415-3) for the examination of water and wastewater testing in 1995. Furthermore, the umu test has been approved as a genotoxicity method of water and wastewater in the ISO conference in 2000 (ISO 13829).

     In this presentation, I would like to introduce the principle of umu test, evaluation of umu test, development of high sensitive umu tester strains to detect nitroarenes, aromatic amines, and dihaloalkanes, development of umu strains expressing phase I and II human drug metabolizing enzymes, development of a high throughput umu-microplate assay systems, and so on.