RABS versus Isolators Professional3 months ago - Mobile Devices - Maiduguri - 31 views
Membrane Filtration Method for Sterility Testing
The Membrane Filtration Sterility Test is the method of choice for pharmaceutical products. An appropriate use of this test is for devices that contain a preservative and are bacteriostatic and fungistatic under the direct transfer method. With membrane filtration, the concept is that the microorganisms will collect onto the surface of a sub-micron pore size filter. This filter is segmented and transferred to appropriate media. The test media are fluid thioglycollate medium (FTM) and soybean casein digest medium (SCDM). FTM is selected based upon its ability to support the growth of anaerobic and aerobic microorganisms. SCDM is selected based upon its ability to support a wide range of aerobic bacteria and fungi (i.e., yeasts and molds). Incubation time is 14 days.
This method is the method of choice for medical devices because the device is in direct contact with test media throughout the incubation period. Viable microorganisms that may remain in or on a product after sterilization have an ideal environment within which to grow and proliferate. This is especially true with damaged microorganisms where the damage is due to a sub-lethal sterilization process. All microorganisms have biological repair mechanisms that can take advantage of environmental conditions conducive to growth. The direct transfer method benefits these damaged microorganisms. The entire product should be immersed in test fluid. With large devices, patient contact areas should be immersed. Nova understands that appropriate modifications are required due to the size and shape of test samples. The method requires that the product be transferred to separate containers of both FTM and SCDM. The product is aseptically cut, or transferred whole, into the media containers. After being transferred, the samples are incubated for 14 days.