A critical aspect of cell development and banking is the assessment that the MCB and WCB are biologically pure, i.e., is free from adventitious microbial agents and adventitious cellular contaminants. The impact of selective agents and antibiotics on the detection of adventitious microbial contaminants based on scientific literature, source, materials and methods used for cultivation would be considered when planning and performing these tests.

The design and performance of specific tests for adventitious microbial agents and adventitious cellular contaminants in microbial cell banks should take into account the properties of the banked cell, the likely contaminants present in the banking laboratory.