Sterility Testing is defined as a test confirming that the products are free from viable microorganisms. It is
very important for medical devices, pharmaceuticals, preparations, tissue
materials, and other materials that claim to be free from viable
microorganisms. Such conditions of materials are known as sterile materials or
devices or any articles. It is an essential part of every sterilization
validation. Sterility testing for products is mainly carried out by direct
inoculation and by membrane filtration.
In the direct inoculation method, the test article is
directly inoculated into two types of media to allow for the detection of both
aerobic and anaerobic microorganisms. Then after inoculation, the media is
incubated for 14 days and finally observed for any microbial contamination.
In the membrane filtration method, the sterile enclosed units are allowed to simultaneously filtrate equal volumes of test samples through two membrane filters. Then samples are incubated in two types of media for 14 days and finally observed for growth of any aerobic and anaerobic microorganisms. Hence, sterility indicators are required to check whether microbial growth occurs or not in terms of sterilization quality and process. So, as defined, Sterility indicators are used to check the quality of sterilization and monitoring of the sterilization process.