Saran's Learn Microbiology

  CHEMICAL METHOD OF STERILIZATION (DISINFECTION) ·        Disinfection is the process of killing of many microorganisms, but not all microorganisms. ·        Disinfection is the chemical method of sterilization. ·        Chemicals used for Disinfection are called as Disinfectants. (a) DISRUPTION OF CELL MEMBRANE i) Alcohols ·        Ethanol is widely used to clean the skin before immunization or venipuncture. ·        It acts mainly by disorganizing the lipid structure in membranes, but it denatures proteins as well. ·        Ethanol requires the presence of water for maximal activity; i.e., it is far more effective at 70 % than at 100 %. Seventy percent ethanol is often used as an antiseptic to clean the skin prior to venipuncture. ii) Detergents ·     Detergents are "surface-active" agents composed of a long-chain, lipid-soluble, hydrophobic portion and a polar hydrophilic group, which can be a cation, an anion, or a nonionic group. ·        Detergent

  STERILIZATION ·       Sterilization is defined as a process in which an article, surface or medium is free of all living organisms. ·        Sterilization is the process of killing of microorganisms. ·        Sterilization was carried out by two methods. A) Physical method a)      Drying b)      Dry heat i.        Flaming ii.      Incineration iii.    Hot air (Hot air oven) c)      Moist heat i.        Pasteurization (Temperature below 100 °C) ii.      Boiling (Temperature at 100 °C) iii.    Tyndallization (Temperature above 100 °C) iv.    Autoclaving (Temperature above 100 °C) d)      Filtration i.        Candle filter ii.      Asbestos filter iii.    Sintered glass filter iv.    Membrane filter e)      Radiation i.        Non – ionizing radiations (Infrared radiation and Ultraviolet radiation) ii.      Ionizing radiations (X – rays, Gamma rays and Cosmic rays) PHYSICAL METHOD OF STERILIZATION (a) DRYING ·        Moisture is essentia