This indicates making all kinds of microbes in vitality including germ’s spores, and verifications on sterilization depend on approving abilities on whether living microbes are removed. 

Practically sterilization is being confirmed by probabilistic verifications on sterilized states by using high-tolerance microbes. The guarantee that sterilizing processes have been completed is different from its methods, and sterilization is measured by biological indicator’s decreased ratio or diminished values before and after sterilizing treatments. Sterilization is occurred when the speed of inactivating microbes is faster than that of microbe’s re-growth or recovering of destroyed cellular materials. Required conditions on sterilization become different according to genetic configurations of microbes. This means that prudent decisions are important in evaluating sterilized states together with selecting sterilizing methods. 

The last results of sterilization differ from microbe numbers having been contaminated in the organization before sterilization. Generally, as much as the microbe’s number is large, it has to be treated in the high density.