TY - JOUR T1 - Effect of Carrier Materials on the Resistance of Spores of <em>Bacillus stearothermophilus</em> to Gaseous Hydrogen Peroxide JF - PDA Journal of Pharmaceutical Science and Technology JO - PDA J Pharm Sci Technol SP - 3 LP - 11 VL - 57 IS - 1 AU - Volker Sigwarth AU - Alexandra Stärk Y1 - 2003/01/01 UR - http://journal.pda.org/content/57/1/3.abstract N2 - The testing of the H2O2 decontamination process using spores of Bacillus stearothermophilus has gained widespread acceptance. Usually, commercially available Biological Indicators (BIs) with a specified resistance to H2O2 are challenged to qualify the process. The question arises whether the resistance of test spores is dependant on the type of carrier material and whether the resistance is representative for the system under test. The objective of the study is to quantify the effect of different carrier materials on the resistance of spores of Bacillus stearothermophilus to H2O2. Materials from which isolators were built, as well as those used in disposables during daily work were investigated. These materials were inoculated with 106 spores of Bacillus stearothermophilus (ATCC 7953). The spore resistance was tested to a well defined H2O2 decontamination cycle by determining the D-value using the “Fractional Negative” method. This paper reports on the effect of different carrier materials to the resistance of the test organism against H2O2. Various materials have significantly increased resistance of the spores and should be avoided in isolator systems. If commercially available BIs are used for process qualification, the resistance of the BI used, the fluctuation in resistance caused by isolator materials, the required log reduction, and at least the bioload of isolator surfaces need to be known. ER -