One of the major properties in the design and development of filter media for food and drug industry is their cleanability. They should be designed regarding to hygienic criteria thereby decreasing residuals and reducing cleaning time and costs. A reproducible test method is necessary to determine or validate the degree of cleanability of filter

media and to indicate areas of poor hygienic design. This work focused on the development of such a filter test and provides information about impurity, whether it occurs or not, and its local resolution. The growth of a microorganism which is introduced as impurity is used for the detection of residues which grow to the surface of the sample and offer a 2-dim-analysis. By this approach, different kinds of filter media can be compared regarding their cleanability against each other.