Controlling Microbial Growth in the Environment

1
Controlling Microbial Growth in the Environment
2
Controlling Microbial Growth

• Terminology of Microbial Control
• Sterilization
• Aseptic
• Disinfection
• Degerming
• Sanitation
• Pasteurization
• Stasis/static
• Cide/cidal

3
Controlling Microbial Growth

• Physical Methods of Microbial Control
• Heat
• Moist Heat
• Boiling
• Autoclaving
• Pasteurization
• Dry Heat
• Refrigeration Freezing

4
Controlling Microbial Growth Contd-

• Desiccation
• Lyophilization
• Filtration
• Osmotic Pressure
• Radiation

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Controlling Microbial Growth Contd-

• Chemical Methods of Microbial Growth
• Phenols and Phenolics
• Denatures
• Alcohols
• Denatures
• Halogens
• Iodine used as antiseptics
• Chlorine used in drinking water and as
  disinfecting bleach
• Bromide used as a disinfectant in hot tubs
  because it evaporates more slowly than chlorine
  at high temperatures.

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Controlling Microbial Growth Contd-

• Chemical Methods Contd-
• Oxidizing Agents
• Peroxides and Ozone
• Reactive oxygen that kills microbes by oxidizing
  their enzymes and preventing their metabolism
• Surfactants
• Soaps and Detergents reduce the surface tension
  of solvents like water and disrupt cell membranes
• Heavy Metals
• Zn, arsenic, Hg, Cu, Ag,- alter 3-d shape of
  proteins

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Controlling Microbial Growth Contd-

• Chemical Methods Contd-
• Aldehydes
• Compounds containing CHO group. Crosslink amino,
  COOH, OH Groups in proteins to denature them
• Use to disinfect medical and dental equipment
• Gaseous Agents
• Used for sterilizing plastic labware, mattresses,
  pillows and things that cannot be easily
  sterilized by heat, chemicals or irradiation.
  Examples include ethylene dioxide and propylene
  oxide.