1. Sterilization By : April 2017 Dr.Samia Sadig Mohamed
Faculty of Medicine
Dept. Microbiology &parasitology
April 2017

2. Aims By the end of the lecture the student should be able to know:
The principle and applications of sterilization

3. Keys
Definitions & Sterilization
Methods of sterilization

4. Hands Spread Disease
wash me !!!

5. History Of
Sterilization

6. Definitions :
Sterilization: A treatment that kills or removes all living cells, including viruses and spores, from a substance or object

7. Definitions : Sterilization / Complete Destruction
- No degrees of sterilization (All or Nothing)

8. Filtration Physical Methods Heat Chemical Methods Moist Dry
Agent acting on the cell membrane
phenols
STERILIZATION
Agent that denature Proteins
Acids
Ionizing radiation
X-rays, beta rays
Gamma rays
Heavy metals
Ultraviolet rays
Oxidizing agents
Dyes
Filtration
Methods of sterilization

9. Physical Methods
Heat
Filtration
Radiation

10. Heat Most Frequent and Widely Used. Always Consider 1. Type of Heat
2. Time of Application
3. Temperature
Endospores are the most heat resistant of all cells.

11. Moist Heat Sterilization
Boiling
Autoclaving

12. Kills Everything Except Some Endospores
Boiling
100° C for 30 Minutes
Kills Everything Except Some Endospores

13. Autoclaving
Steam Under Pressure
121° C for 15 Minutes at
15 lb/in2
Heat-labile Substances will be Denatured
Steam Must Contact the Material

14. TEST Of efficiency of autoclaveBY
(i)Bological: put bacillus spores & see if it die
(ii)using chemical that change its colour
(iii)physical (digital)

15. Dry Heat Sterilization
Direct Flaming
Incineration
Hot-Air Sterilization (Oven)

16. (ALL disposable production.. hospitals &factories…)
Incineration
Burns
Used for
a. Needles
b. Inoculating Wires
c. Glassware
(ALL disposable production.. hospitals &factories…)

17. 160° C for 2 Hours or 170° C for 1 hour Used for a. Glassware b. Metal
Dry Heat (Hot Air Oven)
160° C for 2 Hours or 170° C for 1 hour
Used for
a. Glassware
b. Metal
c. Objects That Won’t Melt

18. Pasteurization
A High Temperature
Is Used For a Short Time
Batch Method
63 °C for 30 Minutes
Flash Method
72 °C for 15 Seconds
Ultra-High-Temperature is 140 °C for 3 seconds

19. Filtration
The passage of a liquid or gas through a filter with pores small enough to retain microbes.
Especially important to sterilize solutions which would be denatured by heat (antibiotics, injectable drugs, amino acids, vitamins.)

20. High-Efficiency Particulate Air Filters 1. Operating Rooms
HEPA Filters
High-Efficiency Particulate Air Filters
1. Operating Rooms
2. Burn Units

21. Acts By Destroying DNA or Damaging It.
Radiation
Acts By Destroying DNA or Damaging It.
Dependent on the Wavelength, Intensity, and Duration

22. Radiatio Ionizing Radiation
1. High Degree of
Penetration
2. Examples
- Gamma Rays
- X-rays
Ultraviolet Radiation …is used for disinfection operating room .
1. Non ionizing
2. Low Degree of Penetration
3. Harmful / Skin / Eyes

23. Definitions :
Disinfection:Removal or killing many organism…partial …not all
Disinfectant : chemical used for disinfection of non living..
Examples :Alcohol:human skin
Phenol :Detol 5%
Iodine:skin
Chlor:Water
H2O2:Wound
Antiseptec:chemical used for disinfection of living tissue..

24. ?
Discuss the Methods of sterilization .

25. Thanks!