Question

True or False please explain

9. (See the recipe for casease agar on page 346.] Cascase agar does not contain an indicator dye because a dye is not necessary to observe a positive and a negative reaction on the medium.

Answer 1

True

First we will understand the about the Casease.

Casease :-

It is an enzyme that bacteria produce to hydrolyze the milk protein casein.

- Presence of Casease can be detected with the test medium milk agar.

- When the platelet milk agar incubated with a Casease +ve organism secreted Casease will diffuse into the medium around the colonies then it produce the clear zone.

-Where as -ve organism don't produce a clear zone

Note :-

Clearing in agar means Casease are present (+ve)

Not clear means Casease are absent (-ve)

Conclusion:-

For Casease, dye is not necessary to observe a positive and negative reaction on the medium.