How Medical Sterilisation Has Improved In The Last 100 Years

sterilizationThe last century has seen a lot of technological advancements in many fields, but perhaps the greatest have come from the medical world. Medical sterilisation, for example, has evolved rapidly and is now safer and more effective than ever before.

Medical sterilisation is the term that refers to any process that eliminates or kills all forms of microbial life such as bacteria, fungi and viruses. Sterilisation can be achieved in many ways by applying chemicals, heat, high pressure, irradiation and filtration. Medical sterilisation has been in existence for approximately 135 years since the invention of the steam autoclave by Charles Chamberland in 1879.

In medicine, surgical instruments and medications that enter part of the body via the bloodstream, biopsy or by penetrating the skin must be sterilised to a high Sterility Assurance Level (SAL). These instruments include anything from scalpels and needles to pacemakers and parental pharmaceuticals.

Here, we’ve put together a short guide that outlines how medical sterilisation has improved in the last 100 years.

Before we begin it is important to review the traditional sterilisation processes, these typically included:

  • Steam
  • Ethylene Oxide (EtO)
  • Low temperature steam and Formaldehyde
  • Ionizing radiation (Gamma or E-beam)
  • Dry heat (hot air)

EtO sterilisation

EtO sterilisation has been a vital technique to the sterilisation of disposable medical devices since it was discovered in 1944 by Phillips and Kaye. In 1980, EtO was used in almost 90% of all sterilised devices. Since then, EtO use for sterilisation purposes has endured ups and downs as a result of a change in environmental laws at the end of the eighties.

This setback was only temporary though because as soon as companies implemented the changes to switch to a 100% EtO gas (instead of the 12% EtO/88% chlorofluorocarbon gas mixture), the sterilisation practice has endured steady growth. This growth has also paved the way for improvements in the field including improved Bls, lower gas concentrations, improved outgassing methods and parametric release.

X-ray sterilisation

X-ray sterilisation is now possible thanks to recent developments in high-energy and high-power electron accelerators. X-ray sterilisation is an alternative to gamma, E-beam and EtO (Ethylene Oxide gas) and allows the capability to turn off the radiation source and to control the X-ray intensity. This technology has been operating successfully for several years in Europe, Japan and North America.


Machines and medical instruments greatly improved over the last hundred years and so has the way that these items are packaged. As medical products needed to preserve their sterility whilst being stored and transported, the demand for better packaging and storage arose. Nowadays nearly all medical goods are terminally sterilised, meaning that they are sterilised already packaged. Such items may be packed in their primary packaging or wrapped in several layers of packaging (such as a shelf or unit pack and shipping carton).

Low-temperature steam and formaldehyde

Low-temperature steam and formaldehyde is a traditional sterilisation process that has been around for over a hundred years but one that continues to evolve. The sterilisation technique has suffered recent scrutiny in the US as there were concerns over the carcinogenicity and toxicity of formaldehyde, also mentioned in this Daily Mail article on the after-effects of Hurricane Katrina.

Improved process control with this technique has allowed the production of sterilizers with negligible environmental emissions as well as low product residual levels.

Ashley Mooney is a Managing Director at Andersen Europe, an industry leader in gas sterilisation techniques. Ashley’s company has been at the forefront of innovation in this sector and is renowned worldwide for its sterilisation products and services.