If you design, develop, produce, install or service any medical device you need to comply with the requirements set out in the relevant European Directives.

A sterile product is one that is free of viable microorganisms. International sterilization standards for medical devices require when it is necessary to supply a sterile product item, that adventitious microbiological contamination of a medical device from all sources be minimized by all practical means. Even so, product items produced under standard manufacturing conditions in accordance with the requirements for quality management systems for medical devices (see, for example, BS EN ISO 13485) may, prior to sterilization, have microorganisms on them, albeit in low numbers. Such products are non-sterile. The purpose of sterilization processing is to inactivate the microbiological contaminants and thereby transform the non-sterile items into sterile ones.

The inactivation of a pure culture of microorganisms by physical and/or chemical agents used to sterilize medical devices often approximates an exponential relationship; inevitably this means that there is always a finite probability that a microorganism may survive regardless of the extent of treatment applied. For a given treatment, the probability of survival is determined by the number and resistance of micro-organisms and by the environment in which the organisms exist during treatment.

Therefore, the sterility of any one item in a batch of items subjected to sterilization processing cannot be guaranteed. So, in a batch of processed items, the sterility has to be defined in terms of the probability of the existence of a non-sterile item being included.

To learn about clinical investigations for medical devices, click here.

Sterilization Standard Requirements of the EU Medical Devices Regulation

The European Medical Devices Regulation 2017/745 (MDR) presents requirements for sterile devices but does not provide a definition of the term ‘sterile’.

Sterile devices are free of viable microorganisms. The BS EN 556 series of sterilization standards define requirements for designating devices as sterile. Parts 1 and 2 of BS EN 556 provide requirements for terminally sterilized devices and aseptically produced devices respectively.

BS EN 556-1 is the European standard specifying requirements for designating a terminally-sterilized device as sterile. It has also been adopted in a number of countries outside Europe, for example, Australia and China. BS EN 556-1 specifies that a probability of a viable microorganism on a device of 10−6 or less (e.g. 10−7, et seq.) has to be achieved in order to designate a terminally sterilized medical device as sterile. The probability of survival of a single microorganism is also known as the sterility assurance level (SAL).

What are the Key Sterilization Standards?

BS EN ISO 11737-1 - Sterilization of health care products. Microbiological methods. Determination of a population of microorganisms on products

This international standard helps users determine the success of sterilization by giving guidance on how to count and characterize microorganisms on health care products. BS EN ISO 11737-1 provides guidance on the enumeration and microbial characterization of the population of viable microorganisms on or in a health care product, component, raw material, or package.

BS EN ISO 15882:2008 - Sterilization of health care products. Chemical indicators. Guidance for selection, use, and interpretation of results

BS EN ISO 15882:2008 specifies guidance for the sterilization of health care products using chemical indicators. This includes guidance for selection, use, and interpretation of results.

BS EN ISO 11135:2014+A1:2019 - Sterilization of health-care products. Ethylene oxide. Requirements for the development, validation, and routine control of a sterilization process for medical devices

BS EN ISO 11135:2014+A1:2019 details how to develop, validate and reliably reproduce an ethylene oxide sterilization process for medical devices that has appropriate microbicidal activity. It describes requirements that, if met, will provide an ethylene oxide sterilization process with appropriate microbicidal activity intended to sterilize medical devices.  It addresses the need for quality systems, staff training, and proper safety measures.

BS EN ISO 11607-1:2020+A1:2023 - Packaging for terminally sterilized medical devices. Requirements for materials, sterile barrier systems and packaging system

The development and construction of packaging systems for terminally sterilized medical devices is complicated and critical to patient safety. BS EN ISO 11607-1:2020+A1:2023 specifies requirements and test methods for materials, preformed sterile barrier systems, sterile barrier systems, and packaging systems intended to maintain the sterility of terminally sterilized medical devices until the point of use.

BS EN ISO 11607-2:2020+A1:2023 - Packaging for terminally sterilized medical devices. Validation requirements for forming, sealing and assembly processes

This is the second of two international standards written to ensure that terminally sterilized medical device packaging allows sterilization, provides physical protection and maintains sterility to the point of use. BS EN ISO 11607-2:2020+A1:2023 looks at validation requirements for forming, sealing, and assembly processes. 

These processes include forming, sealing, and assembly of preformed sterile barrier systems, sterile barrier systems, and packaging systems.

There is no doubt that using standards can help you to effectively meet the sterilization requirements of your medical devices, building crucial trust between you and the rest of your supply chain. With a BSI Knowledge subscription, quality, risk management, and compliance are at your fingertips. Build your own custom collection of standards, or opt for access to our GBM05 Sciences & Health Care module for instant access to over 4,800 documents. Request to learn more.

Sterilizing Equipment Standards

The delivery of a validated and accurately controlled sterilization process is enabled by the use of sterilizing equipment that is designed, constructed, and installed to deliver the sterilization process safely and reproducibly. 

BS EN ISO 17665 sets out the requirements to ensure best practice steam sterilization of medical equipment. By following this standard’s guidelines, the steam sterilization process is more likely to produce sterile medical instruments on treatment and improve overall quality control. Although BS EN ISO 17665 is limited to medical equipment, its requirements and guidelines can also be applied to other health care products. It’s important to remember that an accurately controlled sterilization process is not the only factor that ensures a product is sterile.

Other sterilization equipment standards for particular sterilization processes include:

• Large steam sterilizers (BS EN 285)

• Small steam sterilizers (BS EN 13060)

• Ethylene oxide sterilizers (BS EN 1422)

These standards will be of interest to medical device manufacturers and users of sterilizing equipment. Additionally, there are British Standards for steam sterilizers for aqueous fluids (BS 3970-2) and laboratory sterilizers (BS 2646) that may also be applicable to the processes of some manufacturers.

Ensure the sterilization of your medical devices by adding these key sterilization standards to your collection today.