Methylene Blue Reduction Test (MBRT) procedure
Methylene blue acts as a respiratory pigment when introduced into bacterial cultures. It accepts hydrogen to produce an intracellular oxidation an in so doing be comes decolorized to the levo compound. The rate of depolarization is dependent up on the number of organisms present. The dye is of value in making a rapid survey of the quality of milk the test can be employed to determine roughly the bacterial count of milk.
Requirements: Milk samples, 1 : 20,000 aqueous solution of ethylene blue, sterile 10cc and 1cc pipettes sterile test tube.
Procedure: Pipette 1cc of milk samples into a sterile test tube. Add 1cc of 1 : 20,000 aqueous soln methylene blue. This given a final dye conc. of 1 : 2,00,000. Cork the tubes and shake well. Place them in a 370c water bath; allow to remain for 5 mins. Remove the tubes from the water bath and place them in a 370c incubator. Observe the tubes at half hr. intervals for the first 2 hrs. Reduction is complete when 4/5th of the tube has lost its colour.
Good milk: is one which is not decolorized in 51/2hrs. Containing as a rule less than half million organisms 1cc.
Fair milk: is decolorized in less than 51/2hrs. but not less than 2hrs., containing on a rule 1/2 – 4 million org 1cc.
Bad milk: is one which is decolorized in less than 2hrs. but not less than 20min, containing on a rule 4 – 20 million organism 1cc.
Very bad milk: is one which is decolorized in 20 mins or less containing as a rule over 20 million org 1cc.
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This website is a place where you will find complete information about
Pharmaceuticals cgmp quality systems quality assurance quality control fda approval gmp guidelines standard operating procedures regulatory affairs it is very useful for pharmacists
Methylene blue acts as a respiratory pigment when introduced into bacterial cultures. It accepts hydrogen to produce an intracellular oxidation an in so doing be comes decolorized to the levo compound. The rate of depolarization is dependent up on the number of organisms present. The dye is of value in making a rapid survey of the quality of milk the test can be employed to determine roughly the bacterial count of milk.
Requirements: Milk samples, 1 : 20,000 aqueous solution of ethylene blue, sterile 10cc and 1cc pipettes sterile test tube.
Procedure: Pipette 1cc of milk samples into a sterile test tube. Add 1cc of 1 : 20,000 aqueous soln methylene blue. This given a final dye conc. of 1 : 2,00,000. Cork the tubes and shake well. Place them in a 370c water bath; allow to remain for 5 mins. Remove the tubes from the water bath and place them in a 370c incubator. Observe the tubes at half hr. intervals for the first 2 hrs. Reduction is complete when 4/5th of the tube has lost its colour.
Good milk: is one which is not decolorized in 51/2hrs. Containing as a rule less than half million organisms 1cc.
Fair milk: is decolorized in less than 51/2hrs. but not less than 2hrs., containing on a rule 1/2 – 4 million org 1cc.
Bad milk: is one which is decolorized in less than 2hrs. but not less than 20min, containing on a rule 4 – 20 million organism 1cc.
Very bad milk: is one which is decolorized in 20 mins or less containing as a rule over 20 million org 1cc.
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This website is a place where you will find complete information about
Pharmaceuticals cgmp quality systems quality assurance quality control fda approval gmp guidelines standard operating procedures regulatory affairs it is very useful for pharmacists
Guidelines on Pharmaceutical Manufacturing Pharma Quality Assurance Quality Management System 
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