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* Sterilization: Complete destruction of all 
transmission m.o (bacteria ,virus)
* Disinfection: remove only organisms that
cause disease.
Sterilization
1)Physical method:
a) temperature:
1-Autoclave:
- steam heat to 121c at 1.5 atmospheric pressure for 15
min
- autoclave treatment will inactivate all fungi, bacteria,
viruses and also bacterial spores( quite resistant)
2) Other heat methods:
* Flaming: done to inoculating loops and
needles
* Boiling: boiling water for 15 min (it is
unsuitable for sterilization)
- not effective against many bacteria and
spores
* Dry heat: used for sterilization of glass
wears
- oven is used in dry heat
- can be used on powders and other items
that effected by steam ( doesn’t cause
rusting for the steals)
2) chemical treatment:
* Ethylene oxide gas :
- used to sterilize objects that cannot
survive temp. more than 60 for
3hrs(plastics,optics)
- ethylene oxide penetrate the objects and
sterilize it (paper ,clothe ,plastic)
* Bleach : (use in the house and hospitals)
- kill many organisms but it need 20min for
full sterilization
- it can kill many spores but also ineffective
against resistant spores
- cause rust for stainless steel
* The dry sterilization :
- Dry sterilization condition process(DSP)
used for sterilization of plastics bottles in
beverage industry
- used hydrogen peroxide (30-35% con.)
under vacuum condition
*Ozone:
- - sterilize water,air,and disinfectant for
surfaces
3) Filtration :
-used to remove microbes from solution that
cannot treated in other fashion ( heat
sensitive compounds such as antibiotics
and vitamin)
- filtration uses membrane with small pores
prevent the microbes passage
- cannot remove the virus (why?)
4) Radiation :
-used x-rays, Gama rays, subatomic
particles
- Gamarays penetrate materials used for
sterilization of medical package and
equipment
- ultraviolet (u.v) rays don’t penetrate
materials used for sterilization of surfaces ,
air , iculating cabinate,operating theater)