Dry heat sterilization of an article is one of the earliest forms of sterilization practiced. Dry heat, as the name indicates, utilizes hot air that is either free from water vapor, or has very little of it, and where this moisture plays a minimal or no role in the process of sterilization.
Filtration allows for the exclusion of organisms based upon size. There are many types of filtration techniques, but when sterilizing a system membrane filtration is used. Membrane filtration traps contaminants larger than the pore size on the surface of the membrane.
There are 2 general types of radiation used for sterilization, ionizing radiation and non-ionizing radiation. Ionizing radiation is the use of short wavelength, high-intensity radiation to destroy microorganisms. This radiation can come in the form of gamma or X-rays that react with DNA resulting in a damaged cell.
Moist Heat Sterilization. Water at high pressure level is used in moist heat sterilization. Autoclave is the instrument in which this process is carried out. The temperature of the steam in this method is lower when compared with dry heat sterilization, but the high pressure helps with effective sterilization to take place.