Introduction to sterilization , disinfection.

Sterilization and Disinfection.

 Sterilization means complete destruction of all microorganisms including spores.

 

Disinfection means destruction of vegetative organism that might cause spoilage or diseases.

 It neccessarily dosent mean killing of spores.

 

Decontamination

Decontamination is the process of cleansing to remove contamination, or the possibility (or fear) of contamination.

 

 Sterilization can be caused by many techniques
the methods are :

1. red heat
2. dry heat
3. steam under pressure(autoclaving)
4. steam not under pressure(tyndallization)
5. filtration
6. inceneration

disinfection
chemical disinfection:

1. phenolics
2. hypochlorites
3. alcohol
4. formaldehyde
5. gluteraldehyde
6. iodophores
7. QAC

Types and uses

 The toxicity, harmfull effects and spectrum of suceptibility should be considered while using the disinfectants.

 

 Testing of disinfectants

 Several countries and organisations have offixcial tests for disfectants here the specifications are detailed.

 The basic test involves having a suspension of known colony forming units (cfu/ ml) of Staphylococcus aureus/Psuedomonas aeroginosa and then testing it with several known dilutions of of the disinfectant to be tested.

 After a pre determined contact time aknown volume is removed and neutralizing agent is added that deactivates the disfectant in question.

 The surviving colony forming unite are then calculated.

 A good disfectant reduces the colony forming units by 5 log units in an hour.

 

Usually the best test is usually left to the manufacturers but one test thats simple and easy to use is "in use test".

 

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