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Lecturer
Riaz Khan
🌱
1/7/2023
Sarhad Institute of Allied Health Sciences
1
Sterilization is complete killing, or removal, of all living
organisms from a particular location or material.
It can be accomplished by incineration, non destructive
heat treatment, certain gases, exposure to ionizing
radiation, some liquid chemicals, and filtration.
1/7/2023
Sarhad Institute of Allied Health Sciences 2
The availability of reliable methods of sterilization has
made possible the major developments in surgery.
Sterilization procedures form the basis of many food
preservation procedures, particularly in the canning
industry.
1/7/2023
Sarhad Institute of Allied Health Sciences 3
Method Activity Level Spectrum Uses/Comments
Heat
Autoclave
Boiling
Pasteurization
Ethylene Oxide Gas
Radiation
Ultra Violet
Ionizing
Chemicals
Alcohol
Hydrogen Peroxide
Chlorine
Iodophors
Phenolics
Glutrylaldehyde
Quaternary Ammonium
Compounds
Sterilizing
High
Intermediate
Sterilizing
Sterilizing
Sterilizing
Intermediate
High
High
Intermediate
Intermediate
High
Low
All
Most pathogens, some spores
Vegetative bacteria
All
All
All
Vegetative bacteria, Fungi,
Some Viruses
Viruses, Vegetative Bacteria,
Fungi
Same as above
Same as above
Same as H2O2
All
Most bacteria & Fungi
General
General
Beverages, Plastic hospital eqipments
Potentially explosive; aeration
required
Poor penetration
General, food
Contact Lenses
Water
Skin disinfection
Hand washing
Endospores, Other equipment's
General cleaning
1/7/2023
Sarhad Institute of Allied Health Sciences 4
The simplest method of sterilization is to expose the
surface to be sterilized to a naked flame, as is done
with the wire loop used in microbiology laboratories.
It can be used equally effectively for emergency
sterilization of a knife blade or a needle.
Carbonization of organic material and destruction of
microorganisms, including spores, occur after exposure
to dry heat of 160°C for 2 hours in a sterilizing oven.
1/7/2023
Sarhad Institute of Allied Health Sciences 5
This method is applicable to metals, glassware, and some
heat-resistant oils and waxes.
Moist heat in the form of water or steam is far more rapid
and effective in sterilization than dry heat.
Most vegetative bacteria of importance in human disease
are killed within a few minutes at 70°C or less, although
many bacterial spores can resist boiling for prolonged
periods.
1/7/2023
Sarhad Institute of Allied Health Sciences 6
The autoclave is a sophisticated pressure cooker.
In its simplest form, it consists of a chamber in which the
air can be replaced with pure saturated steam under
pressure.
Air is removed either by evacuation of the chamber before
filling it with steam or by displacement through a valve at
the bottom of the autoclave, which remains open until all
air has drained out.
1/7/2023
Sarhad Institute of Allied Health Sciences 7
Under these conditions, spores directly exposed are killed in less
than 5 minutes, although the normal sterilization time is 10 to 15
minutes to account for variation in the ability of steam to
penetrate different materials and to allow a wide margin of safety.
For example, the spores of Clostridium botulinum, the cause of
botulism, may survive 5 hours of boiling, but can be killed in 4
minutes at 121°C in the autoclave.
1/7/2023
Sarhad Institute of Allied Health Sciences 8
Autoclaves can thus be used for sterilizing any materials that are
not damaged by heat and moisture, such as heat-stable liquids,
swabs, most instruments, culture media, and rubber gloves.
It is essential that those who use autoclaves understand the
principles involved.
1/7/2023
Sarhad Institute of Allied Health Sciences 9
Which are widely used in operating rooms, often use saturated
steam at a temperature of 134°C for 3 minutes.
Air and steam are removed mechanically before and after the
sterilization cycle so that metal instruments may be available
rapidly.
1/7/2023
Sarhad Institute of Allied Health Sciences 10
A number of articles, particularly certain plastics and lensed
instruments that are damaged or destroyed by autoclaving, can
be sterilized with gases.
Ethylene oxide is an inflammable and potentially explosive gas.
Exposure times are usually about 4 to 6 hours and must be
followed by a prolonged period of aeration to allow the gas to
diffuse out of substances that have absorbed it.
Aeration is essential, because absorbed gas can cause damage to
tissues or skin.
1/7/2023
Sarhad Institute of Allied Health Sciences 11
Ethylene oxide is a mutagen, and special precautions are now
taken to ensure that it is properly vented outside of working
spaces.
Used under properly controlled conditions, ethylene oxide is an
effective sterilizing agent for heat-labile devices such as
artificial heart valves that cannot be treated at the temperature
of the autoclave.
1/7/2023
Sarhad Institute of Allied Health Sciences 12
Ultraviolet (UV) light in the wavelength range 240 to 280 nm is
absorbed by nucleic acids and causes genetic damage.
The practical value of UV sterilization is limited by its poor
ability to penetrate.
Apart from the experimental use of UV light as a mutagen, its
main application has been in irradiation of air in the critical
hospital.
It must be remembered that UV light can cause skin and eye
damage, and workers exposed to it must be appropriately
protected.
1/7/2023
Sarhad Institute of Allied Health Sciences 13
Ionizing radiation carries far greater energy than UV
light.
Cathode rays and gamma rays from cobalt-60 are
widely used in industrial processes.
The sterilization of many disposable surgical supplies
such as gloves, plastic syringes, specimen containers,
some foodstuffs, and the like, be cause they can be
packaged before exposure to the penetrating radiation.
1/7/2023
Sarhad Institute of Allied Health Sciences 14
Ionizing irradiation does not always result in the
physical disintegration of killed microbes.
As a result, plastic ware sterilized in this way may
carry significant numbers of dead but stainable
bacteria.
1/7/2023
Sarhad Institute of Allied Health Sciences 15
 This has occasionally caused confusion when it has involved
containers used to collect normally sterile body fluids such as
cerebrospinal fluid.
 The dead bacterial bodies may produce a “false-positive” Gram-
stained smear and result in inappropriate administration of
antibiotics.
 Recent foodborne outbreaks (Escherichia coli) and bioterrorism
(anthrax) have increased the use of ionizing radiation.
1/7/2023
Sarhad Institute of Allied Health Sciences 16
THANK
1/7/2023
Sarhad Institute of Allied Health Sciences 17

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Sterilization.pptx

  • 2. Sterilization is complete killing, or removal, of all living organisms from a particular location or material. It can be accomplished by incineration, non destructive heat treatment, certain gases, exposure to ionizing radiation, some liquid chemicals, and filtration. 1/7/2023 Sarhad Institute of Allied Health Sciences 2
  • 3. The availability of reliable methods of sterilization has made possible the major developments in surgery. Sterilization procedures form the basis of many food preservation procedures, particularly in the canning industry. 1/7/2023 Sarhad Institute of Allied Health Sciences 3
  • 4. Method Activity Level Spectrum Uses/Comments Heat Autoclave Boiling Pasteurization Ethylene Oxide Gas Radiation Ultra Violet Ionizing Chemicals Alcohol Hydrogen Peroxide Chlorine Iodophors Phenolics Glutrylaldehyde Quaternary Ammonium Compounds Sterilizing High Intermediate Sterilizing Sterilizing Sterilizing Intermediate High High Intermediate Intermediate High Low All Most pathogens, some spores Vegetative bacteria All All All Vegetative bacteria, Fungi, Some Viruses Viruses, Vegetative Bacteria, Fungi Same as above Same as above Same as H2O2 All Most bacteria & Fungi General General Beverages, Plastic hospital eqipments Potentially explosive; aeration required Poor penetration General, food Contact Lenses Water Skin disinfection Hand washing Endospores, Other equipment's General cleaning 1/7/2023 Sarhad Institute of Allied Health Sciences 4
  • 5. The simplest method of sterilization is to expose the surface to be sterilized to a naked flame, as is done with the wire loop used in microbiology laboratories. It can be used equally effectively for emergency sterilization of a knife blade or a needle. Carbonization of organic material and destruction of microorganisms, including spores, occur after exposure to dry heat of 160°C for 2 hours in a sterilizing oven. 1/7/2023 Sarhad Institute of Allied Health Sciences 5
  • 6. This method is applicable to metals, glassware, and some heat-resistant oils and waxes. Moist heat in the form of water or steam is far more rapid and effective in sterilization than dry heat. Most vegetative bacteria of importance in human disease are killed within a few minutes at 70°C or less, although many bacterial spores can resist boiling for prolonged periods. 1/7/2023 Sarhad Institute of Allied Health Sciences 6
  • 7. The autoclave is a sophisticated pressure cooker. In its simplest form, it consists of a chamber in which the air can be replaced with pure saturated steam under pressure. Air is removed either by evacuation of the chamber before filling it with steam or by displacement through a valve at the bottom of the autoclave, which remains open until all air has drained out. 1/7/2023 Sarhad Institute of Allied Health Sciences 7
  • 8. Under these conditions, spores directly exposed are killed in less than 5 minutes, although the normal sterilization time is 10 to 15 minutes to account for variation in the ability of steam to penetrate different materials and to allow a wide margin of safety. For example, the spores of Clostridium botulinum, the cause of botulism, may survive 5 hours of boiling, but can be killed in 4 minutes at 121°C in the autoclave. 1/7/2023 Sarhad Institute of Allied Health Sciences 8
  • 9. Autoclaves can thus be used for sterilizing any materials that are not damaged by heat and moisture, such as heat-stable liquids, swabs, most instruments, culture media, and rubber gloves. It is essential that those who use autoclaves understand the principles involved. 1/7/2023 Sarhad Institute of Allied Health Sciences 9
  • 10. Which are widely used in operating rooms, often use saturated steam at a temperature of 134°C for 3 minutes. Air and steam are removed mechanically before and after the sterilization cycle so that metal instruments may be available rapidly. 1/7/2023 Sarhad Institute of Allied Health Sciences 10
  • 11. A number of articles, particularly certain plastics and lensed instruments that are damaged or destroyed by autoclaving, can be sterilized with gases. Ethylene oxide is an inflammable and potentially explosive gas. Exposure times are usually about 4 to 6 hours and must be followed by a prolonged period of aeration to allow the gas to diffuse out of substances that have absorbed it. Aeration is essential, because absorbed gas can cause damage to tissues or skin. 1/7/2023 Sarhad Institute of Allied Health Sciences 11
  • 12. Ethylene oxide is a mutagen, and special precautions are now taken to ensure that it is properly vented outside of working spaces. Used under properly controlled conditions, ethylene oxide is an effective sterilizing agent for heat-labile devices such as artificial heart valves that cannot be treated at the temperature of the autoclave. 1/7/2023 Sarhad Institute of Allied Health Sciences 12
  • 13. Ultraviolet (UV) light in the wavelength range 240 to 280 nm is absorbed by nucleic acids and causes genetic damage. The practical value of UV sterilization is limited by its poor ability to penetrate. Apart from the experimental use of UV light as a mutagen, its main application has been in irradiation of air in the critical hospital. It must be remembered that UV light can cause skin and eye damage, and workers exposed to it must be appropriately protected. 1/7/2023 Sarhad Institute of Allied Health Sciences 13
  • 14. Ionizing radiation carries far greater energy than UV light. Cathode rays and gamma rays from cobalt-60 are widely used in industrial processes. The sterilization of many disposable surgical supplies such as gloves, plastic syringes, specimen containers, some foodstuffs, and the like, be cause they can be packaged before exposure to the penetrating radiation. 1/7/2023 Sarhad Institute of Allied Health Sciences 14
  • 15. Ionizing irradiation does not always result in the physical disintegration of killed microbes. As a result, plastic ware sterilized in this way may carry significant numbers of dead but stainable bacteria. 1/7/2023 Sarhad Institute of Allied Health Sciences 15
  • 16.  This has occasionally caused confusion when it has involved containers used to collect normally sterile body fluids such as cerebrospinal fluid.  The dead bacterial bodies may produce a “false-positive” Gram- stained smear and result in inappropriate administration of antibiotics.  Recent foodborne outbreaks (Escherichia coli) and bioterrorism (anthrax) have increased the use of ionizing radiation. 1/7/2023 Sarhad Institute of Allied Health Sciences 16
  • 17. THANK 1/7/2023 Sarhad Institute of Allied Health Sciences 17