Techniques
for Sterilization are-
Steam: Autoclaves use steam heated to 121–134 °C
(250–273 °F). To achieve sterility, a holding time of at least 15 minutes at
121 °C (250 °F) or 3 minutes at 134 °C (273 °F) is required. Autoclave
treatment inactivates all fungi, bacteria, viruses and also bacterial spores.
Pressure cooking food is also steam sterilization though it is not that
thorough.
Heating: Under heating flaming, incineration, boiling
in water, tindalization, dry heat. These methods inactivate and kill
microorganisms in objects like glass, metals. Boiling in water for 15min
inactivates viruses and kills most vegetative bacteria. However it has no
effect on the spores. Tindilization means boiling for 20 minutes and then
cooling, again re-boiling and cooling for three times. This method is more
effective on sporulating bacteria than just boiling. Dry heat method can be
used on powders and items that bear very high them of heat.
Chemical sterilization: Chemicals like Ethylene oxide, Ozone, Bleach,
Glutaraldehyde and Formaldehyde, Phthalaldehyde, Hydrogen Peroxide, Dry
sterilization process, Peracetic acid and Silver are used in varying degrees.
Products that can get damaged due to heat are subjected to chemical sterilization
for e.g. biological materials, fiber optics, electronics, and plastics.
Ethylene oxide gas and Ozone gas oxidize most organic matter. Though bleach and
Glutaraldehyde and formaldehyde solutions is used as a disinfectant, it’s a
much more concentrated in sterilization also infected item is left immersed for
long duration for effective sterilization. Dry sterilization process with
chemicals is useful for sterilizing plastic bottles medical and pharmaceutical
applications.
Radiation sterilization: Electron beams, X-rays, gamma rays, or
subatomic particles are used for sterilizing disposable medical equipment, such
as syringes, needles, cannulas, IV sets and biological safety cabinets between
uses.
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