Moist heat sterilization

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Moist heat sterilization

  1. 1. MOIST HEAT STERILIZATION6/11/2013
  2. 2. Principle-Denaturation & coagulation ofproteins due to the latent heat present insteamAdvantages of steam –Latent heat liberatedon condensing on a cooler surface increasesthe temprature of that surfaceWhat is Moist heat Sterilization?6/11/2013
  3. 3. Types of Moist heat Sterilization• Pasteurization• Inspissation or Fractional SterilizationHot water belowboiling point• Tyndallization or IntermittentSterilizationBoiling water/steam at atm pr• AUTOCLAVESaturated steam6/11/2013
  4. 4. Pasteurization6/11/2013• 63 C for 30minutesHolderMethod•72 C for 15-20 secondsFlashProcessHeat labile fluids may be disinfected
  5. 5. It is the process ofthickening by dehydration6/11/2013Inspissation Media such asLowenstein –Jensenmedia and Loeffler’sserum are renderedsterile by heating at80-85 C for half anhour on threeconsecutive days
  6. 6. 6/11/2013TyndallisationPrinciple: The first exposure kills allvegetative bacteria and the sporessince they are in a favourablemedium will germinate and be killedon subsequent occasionsThough generally adequate thismethod may fail with spores ofcertain anaerobes and thermophiles
  7. 7.  The Autoclave was invented by CharlesChamberland in 1879AUTOCLAVE6/11/2013
  8. 8. DefinitionAutoclave is a pressurizeddevice designed to heataqueous solutions abovetheir boiling point atnormal atmosphericpressure to achievesterilization6/11/2013
  9. 9. Reliable sterilization with moist heat requirestemperatures above that of boiling water.These high temperatures are most commonly achievedby steam under pressure in an autoclave. .Need for autoclaving:6/11/2013Autoclaving is the preferred method ofsterilization unless the material to besterilized can be damaged by heat ormoisture
  10. 10. 6/11/2013Liquid H2O cannot beheated above 100°C in anopen vesselAt 100°C boilsH2O heated in a sealed vesselPressure risesBoiling point of H2O is raised
  11. 11. 6/11/2013Air removalDownward displacementSteam pulsingVacuum pumpsSuperatmosphericSubatmosphericProcess
  12. 12. 6/11/2013
  13. 13. Biological indicators are the only process indicators that directly monitor the lethality of agiven sterilization process. Spores used to monitor a sterilization process havedemonstrated resistance to the sterilizing agent and are more resistant than thebioburden found on medical devices.Bacillus stearothermophilusThermophilus aquaticusSpore Test6/11/2013If the autoclave does not reach theright temperature the sporeswill germinate when incubated andtheir metabolism will change thecolor of a pH –sensitive chemical.
  14. 14. 6/11/2013Any Questions???
  15. 15. 6/11/2013

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