Sterilization, << `stehr` uh luh ZAY shuhn, >> in medicine and bacteriology, means the killing of germs. Germ killing helps to prevent infection and the spread of disease. Doctors and dentists sterilize their tools before they touch the human body. The bandages and many of the medicines we buy are sterilized before they are packed. Sterilization has been practiced only since the late 1800’s. The English surgeon Joseph Lister introduced antiseptic, germ-killing methods into surgery.
A sterile object has no living germs on it. Proper sterilization is done by fire, steam, heated air, radiation, or certain chemicals. Steam and heated air are the best, for they leave no foreign matter on the sterilized object. Fire is commonly used in the home to sterilize a needle with which to prick a blister or remove a splinter. Steam cabinets are often used to sterilize medical instruments. Heated dry air is used to sterilize oily medicines.
The method of sterilization chosen depends upon the type of germ to be killed. For example, passing a solution through a fine filter will eliminate bacteria from the solution. However, many viruses are small enough to pass through such filters. Bacterial spores, unlike bacteria, usually can withstand boiling in water. But such spores can be killed by high-pressure steam. Some viruses, including the virus that causes AIDS, can be killed by heating at 113 °F (45 °C). However, certain slow viruses and viruslike germs called viroids can be killed only by much more extensive treatments.
The word sterilization is also used to refer to surgical procedures that prevent a female from becoming pregnant or a male from fathering a child. For information on such surgical sterilizations, see Birth control (Methods of birth control).
