How do you show that your sterilization process reliably makes the product sterile?
We support medical device manufacturers in validating sterilization processes: ethylene oxide, radiation and moist heat, with bioburden, residuals and revalidation. Whether a process is validated is decided not by the single cycle but by the chain of evidence from product to routine.
Overview
What do the MDR and the standards require of sterilization validation?
Validation of sterilization processes for medical devices · ISO 11135, ISO 11137, ISO 17665, ISO 11737 · MDR Annex I Section 11 · ISO 13485 Section 7.5.7
Last updated: October 30, 2026
The MDR requires devices labeled as sterile to be processed, manufactured, packaged and sterilized by appropriate, validated methods (Annex I Chapter II Section 11.5). ISO 13485 requires processes for sterilization and sterile barrier systems to be validated before use (Section 7.5.7). How to validate is described in the standards series for each process.
- The process determines the standard. ISO 11135 applies to ethylene oxide, ISO 11137 to radiation, ISO 17665 to moist heat. Each describes development, validation and routine control of the process for medical devices.
- Bioburden is the input variable. ISO 11737-1 sets out how the population of viable microorganisms on a product is determined, and ISO 11737-2 describes the tests of sterility used in defining, validating and maintaining the process.
- Residuals concern ethylene oxide. After the cycle, ethylene oxide and ethylene chlorohydrin remain in the product, and ISO 10993-7 governs how they are determined and assessed. Radiation and moist heat leave no sterilant behind.
- A validation holds for the state that was validated. After changes to product or process, you decide whether to revalidate: ISO 13485 requires validation before use and following changes, where appropriate.
Services
How we support you
Sterilization strategy
Choice of process from product, material, packaging and supply route: ethylene oxide, radiation or moist heat, operated in house or at a contract sterilizer. Deliverable: a reasoned process decision with the open points per product family.
Bioburden determination
Sampling plan, method and recovery under ISO 11737-1, routine bioburden monitoring and, where endotoxin requirements exist, testing under ISO 11737-3. Deliverable: a bioburden report per product family with the plan for routine.
Ethylene oxide validation
Cycle development, installation, operation and performance of the equipment and the microbiological evidence on the product under ISO 11135. Deliverable: a validation report with defined cycle, load pattern and routine plan.
Radiation and moist heat validation
For radiation, establishing and confirming the sterilization dose (ISO 11137-2) with the dosimetric aspects (ISO 11137-3); for moist heat, cycle development and evidence of performance and load under ISO 17665. Deliverable: one validation report per process.
How we work together
What it comes down to
A sterilization process is validated when it has been shown that, for the product, in the packaging and with the load that are actually shipped, the process delivers the required result, and that routine keeps it there. The MDR requires devices labeled as sterile to be processed, manufactured, packaged and sterilized by appropriate, validated methods (Annex I Chapter II Section 11.5). ISO 13485 sets out validation in Section 7.5.7 as a duty of the quality management system. For the US market, 21 CFR Part 820 (QMSR) incorporates ISO 13485:2016 by reference.
| Process | Standard | What has to be shown |
|---|---|---|
| Ethylene oxide | ISO 11135:2014 + Amd 1:2018 | Cycle, equipment and microbiological performance on the product; residuals under ISO 10993-7:2026 |
| Radiation | ISO 11137-1:2025, ISO 11137-2:2013 + Amd 1:2022, ISO 11137-3:2017 | Sterilization dose and dosimetric aspects; bioburden of the product |
| Moist heat | ISO 17665:2024 | Development, validation and routine control of the cycle |
| All three | ISO 11737-1:2018 + Amd 1:2021, ISO 11737-2:2019, ISO 11737-3:2023 | Bioburden, tests of sterility and bacterial endotoxins |
It starts with bioburden: the population of viable microorganisms on the product before sterilization. ISO 11737-1 describes how it is determined. Without a known and monitored bioburden, the evidence that the process reduces it sufficiently has no basis.
With ethylene oxide, residuals come on top. Ethylene oxide and ethylene chlorohydrin remain in the product and are determined and assessed under ISO 10993-7. Aeration after the cycle is therefore part of validating the process and not only of batch release.
A validation does not stay valid by itself. New packaging, a different material, a changed load pattern or a change of provider are occasions to decide whether to revalidate. This page names no interval and no duration for it; they sit in the standard for the process and in the manufacturer's procedure.
Outside this page are the sterile manufacture of medicinal products under Annex 1, general process validation and cleanroom qualification.
Our approach
Our approach
Step
Result
Define the process
A reasoned choice of process and operator, with the products assigned to product families.
Determine bioburden
A bioburden report per product family with a validated method and a plan for routine monitoring.
Validate
A validation report per process with a defined cycle and, for ethylene oxide, assessed residuals.
Hold routine and revalidation
A monitoring plan and an assessment of every change on whether the validation remains valid.
Common pitfalls
Where projects commonly fail
Products are grouped into a family without proving equivalence.
What counts for validation is whether the validated product is the least favorable of the family; the reasoning belongs in the report.
Bioburden is determined for the validation and not watched afterwards.
The standards assume routine monitoring, and a rise in bioburden can violate the assumptions of the validation.
The contract sterilizer delivers a report and the manufacturer does not match it to the product.
Which products, loads and packaging the report covers appears in the provider's report only if the manufacturer specifies it; responsibility stays with the manufacturer.
A new packaging or a changed load pattern passes without assessment.
ISO 13485 requires validation following changes to product or process, where appropriate; the assessment has to precede the change, not follow it.
Quality Management & Compliance
Do any of these pitfalls apply to you?
In a first call we assess your situation and say what needs clarifying first in your case. Without obligation, reply usually within one working day.
FAQ
Frequently asked questions
Sources
- Regulation (EU) 2017/745 (MDR), Annex I Chapter II Section 11
- ISO 13485:2016, Medical devices, Quality management systems, Requirements for regulatory purposes, Section 7.5.7
- ISO 11135:2014 + Amd 1:2018, Sterilization of health-care products, Ethylene oxide, Requirements for the development, validation and routine control of a sterilization process for medical devices
- ISO 11137-1:2025, ISO 11137-2:2013 + Amd 1:2022, ISO 11137-3:2017, Sterilization of health care products, Radiation
- ISO 17665:2024, Sterilization of health care products, Moist heat, Requirements for the development, validation and routine control of a sterilization process for medical devices
- ISO 11737-1:2018 + Amd 1:2021, ISO 11737-2:2019, ISO 11737-3:2023, Sterilization of health care products, Microbiological methods
- ISO 10993-7:2026, Biological evaluation of medical devices, Ethylene oxide sterilization residuals
- EU GMP Guide Annex 1, Manufacture of Sterile Medicinal Products, C(2022) 5938 final of August 22, 2022 (boundary)
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Projects from this industry
What we have worked on in this industry
Latest insights
All insights →Regulations & standards considered
- EU 2017/745 (MDR), Annex I Chapter II Section 11 (infection and microbial contamination)
- ISO 13485:2016 (quality management systems for medical devices), Section 7.5.7 (Particular requirements for validation of processes for sterilization and sterile barrier systems)
- 21 CFR Part 820 (QMSR, US), which incorporates ISO 13485:2016 by reference
- ISO 11135:2014 + Amd 1:2018 (sterilization of health care products, ethylene oxide: development, validation and routine control)
- ISO 11137-1:2025, ISO 11137-2:2013 + Amd 1:2022, ISO 11137-3:2017 (sterilization by radiation: requirements, establishing the sterilization dose, dosimetric aspects)
- ISO 17665:2024 (sterilization by moist heat: development, validation and routine control)
- ISO 11737-1:2018 + Amd 1:2021, ISO 11737-2:2019, ISO 11737-3:2023 (microbiological methods: bioburden, tests of sterility, bacterial endotoxins)
- ISO 10993-7:2026 (biological evaluation of medical devices: ethylene oxide sterilization residuals)
Related topics
Annex 1 (Sterile Manufacturing) →
The counterpart for medicinal products: sterile manufacturing under EU GMP Guide Annex 1
Process Validation →
General validation of manufacturing processes through IQ, OQ and PQ
Cleanroom Qualification →
Qualification of the environment in which medical devices are made before sterilization
ISO 13485 Certification →
The quality management system in which process validation is governed under Section 7.5.7
Technical Documentation & UDI →
The technical documentation in which the sterilization evidence sits
Packaging Validation & Shelf Life →
Packaging and shelf life after sterilization: ISO 11607, transport simulation, aging studies
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