Methods of Sterilization

Autoclaving  * Dry Heat  Sterilization * Ultraviolet Rays

Autoclaving: The Process

How does Autoclaving Kill Bacteria & Micro organisms?

Moist heat coagulates the proteins in any organism and this is aided by the water vapor that has a very high penetrating property, leading to their death. It also causes oxidative free radical damage. This can even, at high enough temperatures, kill prions.

Have you ever wondered, while using your high tech and expensive autoclave, what is it exactly that goes on inside the chamber? How that simple steam kills germs and microbes and disinfect your instruments.

If yes, then read on to find the answer to How does an Autoclave (Steam Sterilizer) work?

Physics behind the working

Under ordinary circumstances (at standard pressure), liquid water cannot be heated above approximately 100 °C or 212 °F in an open atmosphere area. Further heating results in boiling, which is transition from liquid to gas, but does not raise the temperature of the liquid water. However, when water is heated in an enclosed vessel such as an autoclave, it is possible to heat liquid water to a much higher temperature. As the container is heated the pressure rises due to the constant volume of the container. The boiling point of the water is raised because the amount of energy needed to form steam against the higher pressure is increased. Water in the chamber is heated to beyond its boiling point at high pressure thus converting some of it into steam. This steam at high temperature and pressure kills on contact the bacteria and viruses lying on the surface of the load. 

Thus, saturated steam under pressure at the highest temperature compatible with the product is the preferred method of sterilizing medical devices.

Steam sterilization requires direct contact between dry saturated steam and all surfaces of the load at a specified temperature and pressure for a specified time. Direct contact can be prevented by blood, mucous or tissue on load items and/or by the presence of air in the sterilizing chamber.  

It is not possible to ensure adequate steam penetration into wrapped or porous loads and instruments with lumens or cavities unless there is an effective air removal system. 

Disclaimer

The content of this issue is presented for general information only as perceived by the writer of the article. Reader should independently verify the correctness and accuracy of the material before using the same for any purpose whatsoever. The Company or Management or Staff of Puneet Industries or the Writer shall not be responsible for any inaccuracy or error in the article.

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