In the methylene blue reduction
(MRBT) test 1 ml of methylene blue (1: 25,000) is added to 10 ml of milk. The
tube is sealed with rubber stopper and slowly inverted three times to mix. It
is placed in a water bath at 35°C and examined at intervals up to 6 h. The time
it takes for the methylene blue to become colourless is the methylene blue
reduction time (MBRT). The shorter the MBRT, the lower the quality of milk.
Table: Grading of milk samples on
the basis of methylene-blue reduction test in different milk samples.
Quality of milk
Decolourization time
Excellent More than 5 h
Good Between 4 hours and 5 h
Fair Between 3 to 4 h
Poor Less than 2 h
pl let us inform the Life of milk in a room temt And keeping below 5c
ReplyDeletewhile the MBRT comes 1 hrs & 4 hrs & abve 6hrs
Thanx
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klgupta2007@rediffmail.com
Short and sweet article just what i wanted to kno.. it would be lot better to add illustrations and pictures..
ReplyDeleteWhy Methylene blue loses Colour?
ReplyDeleteThe test is recommended to determine the quality of milk sample. It is based on the population bacteria with that of dissolved oxygen. If the sample contains a large population of actively metabolising microorganisms, the concentration of dissolved oxygen will be low because of presence of enormous number of microorganisms. Oxidation-reduction potential of the sample milk would be low.
DeleteThe dye, methylene blue, is an indicator of such reaction. In an aerobic environment, the colour of the dye would be dull and said to be reduced. The raw milk contains large number of enteric organisms and Streptococcus lactis. Both are dye reducers. The rate or duration at which colour of the dye is reduced indicates the quality of milk.
How can we get a good results in MBRT test
ReplyDeleteUse sterilized test tube and rubber stopper.
DeleteHow can we get a good results in MBRT test
ReplyDeletegood article very use full
ReplyDelete