Membrane Filtration (USP 71 Sterility Testing)

At MDS we use Millipore SteritestT and SterisolutestT products to provide a closed-system testing method. With no need to open containers or directly manipulate membranes, the risk of adventitious contamination is greatly reduced.

Open membrane filtration testing requires many more manipulations than direct immersion. This makes it inherently more costly. More manipulations also make this process more open to contamination.

Product immersion is most commonly recommended for sterility testing of medical devices. However, membrane filtration is acceptable (by U.S. FDA) as an alternative when the device may contain or be coated with some inhibitor, such as preservative or drug product, that interferes with microbial growth.

In this procedure, the device is rinsed, and the rinse liquid passed through small-membrane filter paper. The paper is then placed into media selected to encourage growth of any accompanying bacteria or fungi.