sterilization

Definition of sterilization:

1.the act of sterilizing 2.the condition of being sterilized 3.elimination of all living microorganisms.

Steam sterilization basic principle:

six factors are particularly critical to assure successful steam sterilization 1.Time: every microorganisms the exposure time to kill them are different, a minimum amount of time at sterilization temperature is required to kill all the organisms.
2.Temperature: the second critical factor in steam sterilization is the temperature of the saturated steam controlled in the chamber of the sterilizer,this chart illustrates approximately how much time is required to achieve equivalent microbial lethality at different moist heat exposure temperatures you can clearly demonstrates how increasing the temperature dramatically reduces the time needed to achieve sterilization



















3.Moisture: moisture in the steam has a major impact on its ability to denature, or coagulate proteins: hence the importance of using saturated steam. saturated steam is at equilibrium with heated water at the same pressure, which means it contains the maximum amount of moisture without liquid condensate present. saturated steam is recommended for steam sterilization. 4.Direct Steam Contact:direct steam contact with the surface of the object to be sterilized is required for the steam to transfer its stored energy to the object. without direct stem contact to all surfaces, the item will not be sterilized. the amount of energy stored in steam is much higher than dry air or water at the same temperature. 5.Air Removal: air is the biggest deterrent to steam sterilization. air must be removed from the chamber and the load before direct steam contact and sterilization can occur. this is accom-phlished in a steam sterilizer by a series of vacuum pulses prior to sterilization. a small amount of air will always be present in the autoclave chamber, but must be minimized. insufficient air removal, sterilizer chamber vacuum leaks and poor steam quality are the most common causes of sterilization failures. 6.Drying:items must be dry before they removed from the sterilizer,condensation is the natural result of steam ontact with the coller surfaces of the load during the heating and exposure phases. the presence of condensation can cause re-con-tamination of the load when removed from the sterilizer. A steam sterilizer dries the load after sterilization by drawing a deep vacuum in the chamber