The Sporicidal Action of Hydrogen Peroxide and the Use of Crystalline Catalase to Dissipate Residual Peroxide

In a strict sense the germicidal activity of a chemical substance can be accurately evaluated only when the test organisms are quickly and completely freed from the toxic agent after the period of observation. With most germicidal substances this is not easily accomplished. The use of a neutralizing agent always introduces the uncertain influence of the added substance or its reaction products. The usual practice is to eliminate the toxic agent by sufficiently high dilution of the subculture. Since some compounds are bacteriostatic in extremely low concentration this technique is not always reliable. Among the substances that possess strong germicidal activity, hydrogen peroxide is distinctive, in that the residual portion of the compound may be removed quickly and effectively from a solution after the desired period of reaction. This is made possible by the action of the enzyme catalase, which, under favorable conditions, rapidly decomposes hydrogen peroxide into water and molecular oxygen. Catalase-containing materials have been used in sterilization procedures involving peroxide, by Budde (1903), Bbhme (1906), Much and R6mer (1906), and others, but impurities associated with the catalase have materially limited their usefulness. Important recent advances in enzyme chemistry have made it possible to prepare highly active catalase in crystalline form (Sumner and Dounce, 1937). Preparations possessing the purity and potency of crystalline catalase should, we believed, find appli-