Page 36 - MNU PM502 Ph. Micreo practical

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

LAB 2

Disinfectant tests

Disinfectants used in hospitals and laboratories must be tested periodically to

ascertain its potency and efficacy

1- Suspension tests

Determination of phenol coefficient.

Phenol coefficient: is a measure of the bactericidal activity of a chemical

compound in relation to phenol. When listed numerically, the figure expresses

the disinfecting power of a substance by relating it to the disinfecting power of

phenol.

• Disinfectants that are more active than phenol have a coefficient >1 and

disinfectants that are less effective have a coefficient <1.

Extinction time: The shortest time required to kill the whole microorganism

population.

Phenol coefficient tests according to the conditions and factors used in each
test include:

1- Rideal - Walker test.
2- Chick - Martin test.

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