1 of 4

FUNDAMENTALS OF MICROBIOLOGY

STERILIZATION

INTRODUCTION:

  • The process of killing (or)removing bacteria and all other forms of living

Microorganism and these spores from preparation .

IMPORTANCE OF STERILIZATION:

  • Prevents the growth of diseases

​

  • Prevents the spread of diseases

2 of 4

METHODS OF STERLIZATION :

    • Three Methods.

1. Physical method :

a)Dry heat method

b) Moist heat method

c) Sterilization by radiation

[gamma radiation]

​

  1. Chemical method :

phenol and phenol compounds .

alcohols.

heavy metals and their compounds.

detergents.

aldehydes.

disinfectant.

3 of 4

DRY HEAT

HOTAIR OVEN : INSTRUMENT

  • Specially designed instrument –electrically heated and thermostatically controlled.
  • Expose at 1600c for 1 hour.

​

ADVANTAGE:

  • It is suitable method for sterilization of

substance destroyed by moisture.

DISADVANTAGE:

  • Long heating time,high tempreature

4 of 4

MOIST HEAT STERILIZATION

INSTRUMENT : AUTOCLAVE

  • Heating process in autoclave - saturated steam under pressure is allowed to penetrated through materials for 15minutes and temprature 1210c.

ADVANTAGE:

  • Microorganism are killed most efficiency in lesser time due to high pressured saturated steam.

DISADVANTAGE:

  • unsuitable for materials not withstanding temperature of 115℃ or more during heating