Boulder Sterilization’s sterilization validations provide confirmation, by examination and provision of objective evidence, of the globally recognized sterilization methods prescribed in the ISO 11135 series. The EO sterilization validation process includes qualification, process parameters, validations and routine activities, performed to your specific product and package requirements.

Boulder Sterilization works with you to ensure sterilization of the correct product, provide rationalization for the product selection and sterilization method, and assure completion of enough cycles. We monitor the validation cycles using process challenge devices and biological indicators for your specific product monitoring routine production.

Boulder Sterilization ensures completion of bioburden testing and the bacteriostasis and fungistasis test, as well as analysis of the ethylene oxide residuals, ethylene chlorohydrin and ethylene glycol. These demonstrate the safety of the sterilized products by determining compliance with accepted residual limits for the products’ intended use.

The most-used EO sterilization validation is the ISO 11135 “Overkill Method Release” (formally called the “Standard Conventional”) because of its ease of use and robust sterility assurance level results.


  • Establish time, temperature, humidity
  • Loading pattern of the product and separation
  • Maximum elapsed time prior to sterilization done


  • Typically in the chamber itself; vacuum hold
  • Establish time, temperature, humidity


  • Temperature and humidity of the sterilization load
  • Ethylene oxide gas concentration
  • Exposure time (commonly called “dwell time”)
  • Perform 3x half-cycle run lethality and full cycle to confirm


  • Time and temperature maintenance for out-gassing
  • Pressure changes required or needed
  • Loading pattern of the product and separation