subject: The Definition of Sterilization [print this page] The Definition of Sterilization The Definition of Sterilization
The method of sterilization process is through heating, irradiating, and filtrating. Heating method includes autoclaving, dry heating, tyndallisation, and also pasteurization.
In the past, people used fire to sterilize items. This operation was later founded as ineffective because it denatured protein. People found many other disadvantages as time passed. This fact lead many people to look for a better way to sterilize items.
Dry heating was found as ineffective way in sterilizing tools, foods, and other. This method was considered as much more ineffective than sterilizing using moist heat. It took a long time in killing dangerous pathogen. It needed at least 2 hours at 160 degree Celsius to kill the spores.
It is very different from the saturating steam method. If you use saturating steam method, you will take only about 5 minutes to sterilize foods and other things.
To know how effective a sterilization process, we have understand the thermal death time. It is the time when microbes must be placed under certain temperature before all of the microbes in the sample dead. The thermal death point is similar to the thermal death time. It is the temperature when all the microbes are dead.
Nowadays, both ways to know the effectiveness of a sterilization process seem unsatisfactory because they depend on several factors. the factors are the number of microbes in the sample, the condition when we take the sample, and many other issues. To solve this problem, D-value (Decimal Reduction Time) can be taken as an action. Only 10% of the microbes can survive during this time. This is way is much better than the old way of proving the effectiveness of sterilization process.
Moist heat is proven as an efficient way to kill microbes. It is commonly used as a method to sterile metal instruments. Metal instruments should not be exposed to steam because it can cause corrosion. Other instruments made of glass and that short of thing must be treated differently from other kind of instruments because different material must be treated in different way.
