Saber Ahmed Khan
At first it might seem that the direction for defining microbiological
standards for non-sterile manufacturing environments to “scale
down” those already defined for sterile manufacturing. However,
this is not as easy as it would appear. Environmental microbiology
standards for sterile manufacturing are mainly quantitative (colony
forming unit cfu) (cfu per m3, cfu per plate per 4hours, cfu per
cm2, etc.) and are limited to extremely low numbers, often zero
(zero should defined as less than 1). The extremely highly specified environmental controls applied in sterile manufacturing make it
possible to set and achieve the required limits. When environmental
controls are less stringent (as in non-sterile manufacturing), the
numbers of microorganisms not only increases, but also show more
variability.