Addresses various microbiological aspects of the development and validation of an ethylene oxide (EO) sterilization process. Does not address the various factors that can have an effect on the bioburden of the product and on the sterilization process. Provides additional guidance to ANSI/AAMI/ISO 11135-1:2007 and ANSI/AAMI/ISO TIR11135-2:2008 for medical device manufacturers, including those that use contract sterilization facilities or contract sterilization operations.