Abstract: A bacteria impermeable container or ampule (10) contains a liquid growth medium and a substrate-indicator complex. The complex includes a substrate component, e.g., starch, and an indicator molecule, e.g., a dye, a fluorescent molecule, or the like, which are tightly bound and complexed, but which are cleavable by a preselected enzyme. A sterilant passes over a carrier (20) for microorganisms which, upon germination, are capable of rapidly generating large quantities of the preselected enzyme. Following the sterilization process, the carrier is immersed in the liquid growth medium. Any viable surviving microorganisms grow, generating the preselected enzyme. The enzymes cleave the bound indicator molecule from the substrate, resulting in a measurable property change in a couple of hours. Typical property changes include fluorescence, a color change, a change in pH which triggers a pH indicator color change, and the like.