Precise evaluation of the spore reducing activity of photo-catalytic surfaces

Special test applications for the evaluation of the reduction of fungal and bacterial spore load on indoor surfaces were developed. The procedure for testing the efficiency of a photocatalytic active surface material to reduce the number of viable microbial spores involves control and monitoring of environmental and technical parameters such as irradiation (intensity and duration), temperature, humidity and original spore load. Following a certain period of UVA-light-irradiation the extent of viable spore reduction was investigated. The evaluation of the effect on fungal and bacterial spores was performed using a contact plate method. For fungal spores a test cycle with several hours duration before contact plate sampling was employed, for bacterial spores the duration of the test cycle could be shortened and supplemented by a sensitive fluorescence detection method to evaluate the viable spore reduction. Tests are easy to perform and provide traceable and repeatable results. These procedures are supplemental or even superior to previously employed methods.