Wanted: Dead or Alive

Sterilization validation practices in the United States rely heavily on the destruction of microorganisms to establish that sufficient lethality has been delivered. The objective in many instances is demonstration of the poorly defined attainment of "overkill" throughout the load. The complete destruction of resistant spore formers is assumed to support the attainment of a minimum probability of a nonsterile unit (PNSU). In reality, the absence of recoverable microorganisms in sterilization cycle development and validation does not allow for accurate PNSU determination. This article outlines how a strategy inspired by that used for ISO 11137-2, VD_MAX, with positive results can be used to fully support sterilization cycle efficacy. This article is intended to spark interest in a potentially novel approach to sterilization cycle development and can be refined once sufficient experience has been gained with it.