Saturday, March 15, 2008

WHY STERILIZERS USE STEAM

It is obvious that heat and moisture are necessary to achieve the death of microorganisms. The most convenient vehicle of both heat and moisture is saturated steam, because it has the following :

1.Heat
2.Moisture
3.Its action is rapid
4.It is relatively inexpensive
5.It is plentiful or easily created
6.It is easily controlled
7.It is easily removed after it has been used by a drying process
8.It is non toxic

The bulk of the articles that need to be sterilized can stand temperatures of 134 C and are not ruined by moisture. There is a small percentage of articles that are either heat sensitive, moisture sensitive, or both, and an equally small percentage that cannot be sterilized by steam due to their physical properties. An example of items falling into these categories is as follows :

1.Heat sensitive – plastics
2.Moisture sensitive – ink and some types of paper products
3.Cannot be sterlized by steam – oil

Adapted from : Atherton

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