kuliah 9, phenol coefficient2

8/18/2019 Kuliah 9, Phenol Coefficient2

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Prof. Dr. Marlina, MS., Apt.



Phenol coefficient

is a measure of the bactericidal activityof a chemical compound in relation tophenol.

When listed numerically, the gureexpressing the disinfecting poer of a

substance by relating it to thedisinfecting poer of phenol may be afunction of the standardi!ed test performed.

http://en.wikipedia.org/wiki/Bactericidal

http://en.wikipedia.org/wiki/Phenol

http://en.wikipedia.org/wiki/Disinfection

http://en.wikipedia.org/wiki/Standardized_test

http://en.wikipedia.org/wiki/Standardized_test

http://en.wikipedia.org/wiki/Disinfection

http://en.wikipedia.org/wiki/Phenol

http://en.wikipedia.org/wiki/Bactericidal



Phenol coefficient test is best knownscreening test in which potency of a

disinfectant is compared with that ofphenol.

A series of a dilutions of phenol and thedisinfectant being tested are prepared.



A standard amount of Salmonella tyhpiiand Staphylococcus aureus are addedto each dilution"

the dilutions are then placed in a #$ to

%&o' ater bath. At ()minute intervals, samples are

ithdran from each dilution and used

to inoculate a groth medium, hich isincubated for to or more days andthen examined the groth.



*f there is no groth in the grothmedium, the dilution at that particulartime of sampling +illed the bacteria.

he highest dilution that +ills thebacteria after -o min. exposure, but notat (min.

is used to calculate the phenol

coecient. his is done by dividing thereciprocal of the appropriate phenoldilution.



/or example,

the 0ideal)Wal+er method gives a

0ideal)Wal+er coecient and the 1.S. Department of

Agriculture method gives a 1.S.Department of Agriculturecoecient.



o calculate phenol coecient "

the concentration of phenol at hich thecompound +ills the test organism in -$

minutes, but not in ( minutes, is divided by the concentration of the test

compound that +ills the organism under thesame conditions

2or, probably more common, dividing thedilution factor at hich the tested substanceshos activity by the dilution factor at hichphenol shos comparable activity3.



he phenol coecient may bedetermined in the presence of astandard amount of added organicmatter or in its absence.



A related ay to express thebactericidal activity of an agent 2at agiven concentration3 is by employingthe formula 4

+ 5 67'8 here 6 is the number of surving cells,

' is the concentration of agent applied and is the time for hich the agent is applied,

so + is inversely proportional to dose

2'8 is collectively called dose3.



Phenol coecient test is best +nonscreening test in hich potency of adisinfectant is compared ith that ofphenol.

A series of a dilutions of phenol and thedisinfectant being tested are prepared.

A standard amount of Salmonella tyhpiiand Staphylococcus aureus are added toeach dilution" the dilutions are thenplaced in a #$ to %&o' ater bath.



At ()minute intervas, samples areithdran from each dilution andused to inoculate a groth medium,

hich is incubated for to or moredays and then examined the groth.

*f there is no groth in the grothmedium, the dilution at that particulartime of sampling +illed the bacteria.



he highest dilution that +ills the bacteriaafter -o min exposure, but not at (min.

is used to calculate the phenol coecient.

his is done by dividing the resiprocal ofthe appropriate phenol dilution.

0ead more4http477i+i.ansers.com797Phenol:coecient:test:in:microbiology;ix!!-t<+i=>?@

kuliah 9, phenol coefficient2

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