Please enable JavaScript.

Coggle requires JavaScript to display documents.

Sterilisation (Chemical Methods (Alcohols, Aldehydes, Phenols, Halogens,…

- - - - Red Heat
        
        forceps , needles , inoculating wires. Held over flame of Bunsen burner until red
      - Flaming
        
        Glass slides . scalpels . held over flame of bunsen burner without allowing it to get red
      - Incineration
        
        soiled dressings, bedding, animal carcasses . Reduced to ashes
      - Hot air oven
        most widely used
        
        glassware. surgical instruments , liquid paraffin. circulating hot air (:checkered_flag:160C for 2hours)
        
        Precautions .
        
        1.Items must be perfectly dry , evenly spaced and non-inflammable
        
        let the oven cool for 2 hours, items may crack if removed suddenly.
        
        3.wrap petridishes in paper and plug testtubes with cotton
      - Sterilisation Controls
        
        Bacillus subtilis subsp. niger spores
        
        Thermocouples
        
        Brownes tube with green spot
        (after :checkered_flag: 2hrs*160C - green color )
    - - . >100 C
        at higher pressures
        
        :star:Autoclave :star:
        
        Principle
        1.saturated steam comes in contact with a surface and releases its latent heat as it condenses .
        the condensed water also provides a moist conditions for killing microbes :question:
        
        materials which cant withstand hot air oven--
        culture media. rubber gloves . dresses
        
        :checkered_flag:121C*15mins
        pressure : 15psi
      - <100 C
        
        Pasteurisation of Milk
        
        Holder Method
        :checkered_flag:63C * 30mins
        
        Flash Method
        :checkered_flag:72C * 20sec then cooling quickly to =<13C
        safer method : :star:coxiella burnetti can survive holders method
        
        Inspissation
        
        Lowenstein-Jensens and Loefflers serum
        :checkered_flag:80-85C * 30mins for 3 consecutive days
        
        Vaccine Bath
        
        Bacterial Vaccines - :checkered_flag: 1hr60C
        Serum or body fluids - :checkered_flag: 1hr56C for several succesive days
        
        Low Temperature Steam Formaldehyde
        (LTSF)
        
        sub atmospheric pressure and 75C
        with formaldehyde vapour
        used if material cant handle 100C
      - at 100 C
        
        Boiling
        ( :checkered_flag:10-30 mins)
        
        syringes , rubber stoppers.
        used normally when better methods are not available
        
        Tyndallisation
        ( :checkered_flag:20mins for 3 successive days)
        
        Is Steam sterilisation at intervals
        1st - vegetative forms dead
        2nd - spores become vegetative during intervals
        then - they killed too
        
        Steam Steriliser
        ( :checkered_flag: 90mins)
        
        -for media which is decomposed at higher temperatures (autoclave)
        -thermophiles survive
        -Kochs or Arnolds steam steriliser
      - Sterilisation control
        
        Bacillus Stearothermophilus
        used in LTSF
        
        Thermocouple - records temprature with a potentiometer
        
        Bacillus Stearothermophilus
        
        Browns tube- red solution turns green
        at 121C * 15mins
        
        Autoclave tapes
  - - - for purification of water.
        candle shape . different levels of porosity
        1.Diatomaceous earth filter :Berkefeld
        2.Unglazed porcelain : Chamberlalnd
    - - cellulose esters - nitrocellulose is commonly used
        used in water analysis and sterility testing
        0.22Um pore is smaller than bacteria --- used for bacterial counts of water
    - - used to produce bacteria-free air to a room
        HEPA filters (high efficiency particulate air)
        pore size - >=0.3um