Medical Device Steam Sterilization and the Impact of ISO 17665

Is steam sterilization the best decision for your company’s medical devices? You may have decided it is and are already looking for a sterilization partner to reliably handle the process for you. Or you may be undecided based on the alternative sterilization options which are widely available.

Whichever best describes your situation, it is helpful to have a good understanding of how steam sterilization works, what it works best with, and how ISO 17665 “Sterilization of health care products—Moist heat—Part 1: Requirements for the development, validation, and routine control of a sterilization process for medical devices” influences processes. We’ll break this down to help you make the best decision for your device, your workflow, and your company.

How does steam sterilization work?

Steam sterilization may seem like a simple process. Steam destroys pathogens, right? That is correct to some extent. But it is an intricate process with best practices, specific equipment, and a series of processes for optimal outcomes.

Wet heat transfer is one of the more time-efficient methods of sterilization and is actually one of the most reliable sterilization methods. Pressurized steam breaks down pathogenic structural proteins and enzymes to render them nonfunctional. This process ultimately kills off the microorganisms by destroying their ability to reproduce.

Steam sterilization inactivates:

  • Fungi (Yeasts/Molds)
  • Bacteria
  • Viruses
  • Bacterial spores

Side benefits include its environmentally friendly process and quick results.

What equipment is used in steam sterilization?

A steam sterilizer is called an autoclave. This machine performs a variety of functions to properly eliminate pathogens from medical devices. At its most basic, it is a heat sterilization process that uses heated steam between 121-134° C. It has an average holding time of 15 minutes or more at 121°C, or three minutes at 134°C (approximate equivalent minutes of steam sterilization at 121°C delivered to a product load). This time may be lengthened for surgical instruments in layers of cloth, or for liquids.

Specific factors to achieve sterilization include:

  • Proper temperature and time
  • Complete displacement of air using steam

What devices are ideal for steam sterilization?

Devices best suited to steam sterilization are surgical instruments and implantable medical devices. It is not a good choice for implantable sensor systems, however. You probably already realized that wet heat and electronic components do NOT mix!

Other devices that do not do well with steam sterilization:

  • Some plastics
  • Fiberoptics
  • Biological materials
  • Most polymers

High carbon steels can be at risk for a corrosive effect, which can dull instruments. There are pre-sterilization steps that can be taken to avoid such a risk. One is to dip the high carbon steel device in an anti-corrosive solution (anodize) prior to placing in the autoclave.

How does ISO 17665 influence steam sterilization requirements and processes?

The International Organization for Standardization (ISO) created the 17665 steam sterilization requirements for sterilization of healthcare products using moist heat. This guide outlines the development, validation, and routine control of the sterilization process, and is utilized by any reputable sterilization resource (whether internal or external).

Compliance with the guidelines not only ensures proper sterilization, but also the ability to confidently assert that at a high probability no viable microorganisms remain on the device after sterilization. It also extends to:

  • The microbiological status of incoming raw materials and/or components
  • The validation and routine control of any cleaning and disinfection procedures used on the product
  • The control of the environment in which the product is manufactured, assembled, and packaged
  • The control of equipment and processes
  • The control of personnel and their hygiene
  • The manner and materials in which the product is packaged
  • The conditions under which product is stored

If you are outsourcing steam sterilization to an external partner, you’ll want to verify they are following all ISO 17665-1:2006/(R)2013 requirements.

Is steam sterilization right for your devices?

Does your device fit the profile for steam sterilization? Hopefully, the above information answered your questions. If you have additional inquiries about the process, or still have concerns if it is right for your device, reach out to our service team at Life Science Outsourcing. We can provide more detail to help you identify the right sterilization process for your devices.

Learn more about our Sterilization Validation Services (SVS) division, including steam sterilization. You can reach our service team for assistance by email at or by phone at 714-672-1090.


The Life Science Outsourcing team is ready to help you with your project.

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