Milk agar medium

Hello everyone ,

Today Iam here with some explanation on milk agar medium.

Milk agar is media mainly use to enumerate microorganisms present in milk and milk . But in this section I will be using milk agar for confirmation of proteolytic organisms.

Proteolytic organisms have the ability to produce proteases , an enzyme which bring about degradation of peptide bonds of protein. 

IT'S very easy  to make  this media 

   Add 10 ml of milk ( 1 gm of milk solids ) into 90 ml of  Nutrient agar 

Mostly the plate is seen crowded as this media is very much enriched and  allows all type of organism to grow . Proteolytic organisms can been differentiated from all other organisms as they show zone of clearance/ hydrolysis around the colony.

But how clear zone came-

As these organism produce  protease enzyme which can hydrolyze casein present in the  milk , which result in clearance .

Thank you
-Dixy