Filters used for sterile filtration should be tested as standard for their bacterial retention capacity. This test is offered at BioChem in the Microbiology department.

The Bacterial Retention Test, already established at BioChem, is designed to show that the filter membrane absorbs a defined quantity of bacteria. The logarithmic reduction value (LRV) is an acceptance criterion that can be calculated using this test. The test can be carried out in accordance with various standards, e.g. ASTM F-0838.  

We also offer the product-specific bacteria retention test. For this, a filter that corresponds to the filter used for routine filtration (e.g. PES membrane) is exposed to the product to be filtered. The conditions during the routine process are scaled to laboratory conditions. This means that the test is carried out in the laboratory with a Ø 47 mm filter, for example, and all parameters relevant to the routine process are calculated as a function of this smaller filter surface. Relevant parameters are, for example, the filtration volume, the duration of filtration, the flow rate and the pressure to which the filter is exposed.  

Based on the results of the product-specific filter validation, it can be shown that the integrity of the filter is given during and after the filtration process.