1 STERILIZATION AND DISINFECTION CHAPTER 12
Dec 26, 2015
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STERILIZATION AND DISINFECTION
CHAPTER 12
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Terminology
Disinfection- reduction of number
– Disinfectant used on inanimate objects (most do not kill spores)
– Antiseptic can be used on skin
Sterilization (Autoclave)20 mins at 121 degrees and 18 PSI
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Chemical Antimicrobials Potency
Phenol coefficient
Filter paper method
Use dilution test
mic: minimum inhibitory conc
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Microbial Sidebar 27-2
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Disinfectant Selection Criteria Time of action
Safety
Microbe range
Penetration
Preparation
Cost
Odor
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Mechanisms of Action Protein damage
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Mechanisms of Action
Membrane damage
Other
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Disinfectant Types Soaps/detergents
Acids/Alkalis
Heavy Metals
Halogens
Such as mercury
Such as iodine, bromineand chlorine
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Disinfectants (cont.) Alcohols
Phenolics
Oxidizers
Alkylating agents
Dyes
Peroxides
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Alkylating agents
Ethylene oxide
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Physical Antimicrobial Agents Heat Application
– Dry Heat
– Moist Heat
– Pasteurization
171 deg, 1 hr
62.9 for 30 mins
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The Autoclave
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Fig. 27-1
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Time (min)
Su
rviv
al f
ract
ion
(lo
g s
cale
)
20 30 40 50
60°C
70°C
50°C
Decimalreductiontime (D)
100
10
1
0.1
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Fig. 27-3
Tem
per
atu
re (
°C)
100
110
120
130
Total cycle time (min)
0 10
Temperatureof object beingsterilized
20 30 40 50 60
Temperatureof autoclave
Sterilization time
Autoclave time
Stopsteam
Beginpressure
Flowingsteam
Steam supplyvalve
Steam enters here
Thermometerand valve
Steamexhaustvalve
Chamberpressuregauge
Air exits through vent
Jacket chamber
Steam exhaust
Door
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Physical Antimicrobial Methods
Refrigeration/Freezing
Dessication
Freeze-drying
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Physical Antimicrobial Methods
Radiation
Filtration
0.45 micron
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Fig. 27-4
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Physical Antimicrobial Methods
Osmotic Control
Sugar or salt