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20 Cards in this Set
- Front
- Back
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Sterilization
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destruction of all forms of microbes: cells, endospores, viruses
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Disinfection
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killing, inhibition, or removal of pathogens from INANIMATE objects
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Antisepsis
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Destruction of pathogens on LIVING TISSUE
via chemicals |
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Sanitization
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reduction of microbial populations to levels safe according to public health standards
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What is Death of a microbe?
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When it can't grow anymore
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Mechanisms of death (3)
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1.no water no life
2. alteration of membrane permeability 3. damage to proteins and nucleic acids (disrupts replication and metabolism) |
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dry heat is required for:
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powders and oils
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Hot air oven kills at what temp? how long? and how?
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160 C; 2 hours, oxidation reactions (alter proteins) and removal of water, for powders oils and glassware
does not erode or corrode |
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Boiling water
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100 C, doesn't sterilize, kills by denaturing proteins
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Autoclave
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121.5 C, sterilizes, 15-30 to kill, Fractional sterilization (Tyndallization - repeated 3x)
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Pasteurization
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not sterilization, used for food, increase shelf life, spores not affected
destroys Mycobacterium tuberculosis and Coxiella burnetii (Q fever) LTLT (30', 62.9C), HTST (flash- 15s, 71.6C) Ultrapasteurization (3s, 82C) |
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Hot oil
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160C, used by dentists, sterilizes, does not corrode or erode metal, bad b/c gotta wipe off oil and may reintroduce microbes
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Filtration
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membrane: cellulose acetate, nylon, nitrocellulose, polycarbonate
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UV light
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thymine dimers, random mutation, surface sterilization, gram positive less susceptible
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Ionizing Radiation
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Gamma and xrays, force e- out of shells, destroy nucleic acids and proteins
for heat sensitive materials (pharmaceuticals, plastics) |
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Cobalt 60:
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FDA used to kill Trichinella spirilis(roundworm)
Exception: deinococcus radiodurans |
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Microwaves
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move water molecules
heat and dessication no other specific activity again microbes |
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Laser
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Light Amplification by Stimulated Emission of Radiation
concentrated light kills instantly coverage is problem |
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Ultrasonic vibrations
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Cavitation: formation and implosion of bubbles
Known as 'cold boiling' use of cavitrons requires liquid |
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Preservation Methods (3)
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1. Dessication (no water no life)
2. Sugars and salts (osmotic pressure, water diffuses out) molds can tolerate high sugar though 3. Low temp- lowers metabolic rate and growth rate |
