Understanding Ethylene Oxide (EtO) Sterilization in Kitting Operations

Sterility is critical to patient safety. Medical products that come into contact with patients must be free of viable microorganisms to help reduce the risk of infection and other adverse events. For many healthcare products, the gold standard is terminal sterilization—a process in which products are assembled, packaged, sealed, and then sterilized as a finished unit.

This approach ensures that the complete kit, including all components and packaging, has undergone a validated sterilization process before it reaches the clinical environment.

Ethylene oxide plays a unique role in healthcare because many medical products cannot tolerate the high temperatures, moisture, or radiation associated with other sterilization methods. In fact, nearly 20 billion medical devices¹ rely on EtO sterilization because it effectively sterilizes complex and sensitive materials without causing damage.

For custom procedure trays and medical kits, EtO is especially valuable because it can penetrate layers of packaging and reach hard-to-access areas within assembled pallets, helping ensure every component meets strict sterility requirements.

One of the most common questions customers ask when viewing manufacturing videos or touring a facility is: “Why aren’t employees wearing gloves?”

The answer points to terminal sterilization.

During medical kit assembly, workers handle products in accordance with current Good Manufacturing Practices (cGMP). However, the kits are not yet sterile. The sterility of the finished product does not depend solely on conditions during assembly. It is achieved through the validated terminal sterilization process that occurs after the kit is fully assembled and packaged.

The final EtO sterilization cycle is designed to eliminate viable microorganisms throughout the packaged kit, providing a highly reliable Sterility Assurance Level (SAL) of 10⁻⁶, meaning there is only a one-in-one-million probability of a viable microorganism surviving the validated process.

Sterilization is much more than simply exposing a product to EtO. The process involves multiple, manual steps to ensure product safety and regulatory compliance, including:

1. Kit assembly and packaging – Components are assembled into the final kit configuration and sealed.
2. Sterilization processing – The packaged kits undergo a validated EtO sterilization cycle.
3. Aeration – Following sterilization, products must undergo a controlled aeration period to allow residual ethylene oxide levels to dissipate to acceptable limits that are governed by ISO standards.
4. Quality review and release – Documentation, process records, and quality controls are reviewed before product release.
5. Distribution center shipment – Once released, products are transported to distribution centers and prepared for customer delivery.

These steps are essential to ensuring every sterile kit meets rigorous quality and regulatory standards before it reaches a healthcare facility.

Owens & Minor’s sterilization program is supported by experienced sterility assurance professionals and follows established industry standards for the development, validation, and control of the EtO sterilization processes. The program includes periodic cycle reviews, requalification activities, and third-party validation testing performed by ISO 17025-certified laboratories.

When a sterile kit arrives at a hospital or surgery center, healthcare providers should be confident that extensive controls, validation activities, and quality checks have taken place long before that product reached them at their facility.

Sterilization is often the final step in the manufacturing journey, but it could be considered one of the most important. Through validated terminal sterilization using ethylene oxide, Owens & Minor helps ensure that healthcare providers receive safe, sterile products that support the delivery of quality patient care every day.

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