Disinfection: Importance and Methods

 What is disinfection?

Disinfection is the process, which involves the elimination of most pathogenic microorganisms (excluding       bacterial  spores) on inanimate objects. •Chemicals used in disinfection are called disinfectants. Different   disinfectants have different target ranges, not all disinfectants can kill all microorganisms.

 Importance of disinfection:

To minimise number of organisms in the population worldwide. The method of disinfection is used         internationally for the safety of humans, to decrease the scale of transmission of diseases. A large emphasis of   sterilisation and disinfection has been placed in the food industry, water sanitisation and medical care and   hospitals.  As these have found to be largest affected organisations with microorganisms and modes of transmission   amongst the population. Different disinfectants are used in different industries, which target the specific flora.

 Disinfection techniques are classified according to:


Liquid (Alcohols, Phenols)

Gaseous (Formaldehyde vapor, Ethylene oxide)

  Spectrum of activity

High level

• Intermediate level

• Low level

Mechanism of action

• Action on membrane (Alcohol, detergent)

• Denaturation of cellular proteins (Alcohol, Phenol)

• Oxidation of essential sulfhydryl groups of enzymes (H2O2, Halogens)

• Alkylation of amino-, carboxyl- and hydroxyl group (Ethylene Oxide, Formaldehyde)

• Damage to nucleic acids (Ethylene Oxide, Formaldehyde)

Common uses of disinfectants:

Aldehydes: surface disinfection, fumigation of rooms, chambers and operating theatres.

Alcohol: 70% aqueous alcohol is more effective at microbial killing. 70% Ethyl alcohol is used as antiseptic on skin.

Phenol:’ first used by Lister to prevent infection in surgical wounds. In high concentrations used as a disinfectant and in low concentrations as an antiseptic.

Halogens: Iodine (antiseptic), Chlorine (bleach)

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