ABSTRACT
A rigorous evaluation of microbial contamination for cleaning validation has had a low profile during the first decade of cleaning validation [l]. The focus, at least in terms of acceptance criteria, has been on chemical residues , specifically residues of the active and the cleaning agent. The Food and Drug Administration (FDA) guidance document on cleaning validation specifically says that the guide is "intended to cover cleaning for chemical residues only." Despite that main concern with chemical residues, the guidance document also states that "microbial aspects of equipment cleaning should be considered." The emphasis in the guidance document, however, relates to microbial proliferation during storage [2] .
