1. STERILIZATION AND DISINFECTION
CHAPTER 12

2. 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

3. Chemical Antimicrobials
Potency
Phenol coefficient
Filter paper method
Use dilution test
mic: minimum inhibitory conc

4. Microbial Sidebar 27-2

5. Disinfectant Selection Criteria
Time of action
Safety
Microbe range
Penetration
Preparation
Cost
Odor

6. Mechanisms of Action
Protein damage

7. Mechanisms of Action
Membrane damage
Other

8. Disinfectant Types Soaps/detergents Acids/Alkalis Heavy Metals
Halogens
Such as mercury
Such as iodine, bromine
and chlorine

9. Disinfectants (cont.) Alcohols Phenolics Oxidizers Alkylating agents
Dyes
Peroxides

10. Alkylating agents
Ethylene oxide

11. Physical Antimicrobial Agents
Heat Application
Dry Heat
Moist Heat
Pasteurization
171 deg, 1 hr
62.9 for 30 mins

12. The Autoclave

13. Survival fraction (log scale)
Fig. 27-1
Decimal
reduction
time (D)
100
50°C 10
Survival fraction (log scale)
70°C
60°C 1
0.1 10 20 30 40 50
Time (min)

14. Fig. 27-3 Chamber pressure gauge Steam exhaust Steam exhaust valve
Door
Jacket chamber
Thermometer
and valve
Air exits through vent
Steam supply
valve
Steam enters here
Autoclave time
130
Stop
steam
120
Temperature (°C)
Begin
pressure
Sterilization time
110
Flowing
steam
Temperature
of object being
sterilized
Temperature
of autoclave
100 10 20 30 40 50 60
Total cycle time (min)

15. Physical Antimicrobial Methods
Refrigeration/Freezing
Dessication
Freeze-drying

16. Physical Antimicrobial Methods
Radiation
Filtration
0.45 micron

17. Fig. 27-4

18. Physical Antimicrobial Methods
Osmotic Control
Sugar or salt