micro >>> | Sterilization| Any process that kills or removes all forms of life, include fungi, bacteria, viruses and spores forms. ------------------------ Methods: 1- Heat: - dry heat. - moist heat. 2- radiation 3- chemical 4- filtration Heat, Radiation & Chemical sterilization kill the micro organisms but Filtration removes the micro organisms without killing them. ------------------------------- • Dry Heat Sterilization : - suitable for heat stable & moisture sensitive substance. - destroy micro organisms by causing irreversible damage to all metabolic function by oxidative way. - by " Oven " : the proper time & temperature is : 160ْ c for 2 hours or 170ْ c for 1 hours or 180ْ c for 1/2 hours. -------------------------------- • Moist Heat Sterilization : - suitable for stable items " aqueous preparation & surgical material " - destroy micro organisms by causing denaturation & coagulation of essential protein. - by " Autoclave " : the proper time & temperature is : 121-124ْ c for 15 min or 130-138 ْc for 3 min. ------------------------------- • Filtration: Filtration destroys micro organisms by physical removal of viable organisms rather than killing them. - types of filters :filters can be made of several different material such as: nitrocellulose & poly ether sulfone ( PES ) 1- Depth Filters: unglazed ceramic filter , sintered glass filter 2- Membrane Filters. ---------------------------- * Laminar Flow: Air is drawn throw a HEPA filter " High Efficiency Particulate Air filter " Its pore size = 0.3 micron ( it will exclude 99.9% of micro organisms )
Posted on: Mon, 23 Sep 2013 19:53:32 +0000
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