Biological Indicator (BI)

A population of microorganisms inoculated onto a suitable medium (e.g. solution, container or closure) and placed within appropriate sterilizer load locations to determine the sterilization cycle efficacy of a physical or chemical process. The challenge microorganism is selected based upon its resistance to the given process. Incoming lot D-value and microbiological count define the quality of the BI.

Source: GMP Draft Annex 1