3. The term given to all the Tests that raw
milk go through to assess the Quality Of
Incoming Milk Before it is Accepted
And Weighted.
It is Performed for Each can/Tanler Of
Milk For Doubtful Quality.
Platform
Tests
7. Clot On Boiling(COB)
Objectives: To determine the stability of milk
for heat processing.
Procedures::
1. Take 5 ml of milk in the test tube.
2. Put this on boiling water bath for 5 minutes.
3. Remove the tube from water bath without
shaking.
4. Note any acid smell or precipitated particles on
the sides of the test tube.
Sample showing precipitated particles are recorded
as positive C.O.B. test. Such milk is rejected on the
platform.
8. Alcohol Test
Objective:
To detect abnormal milk such as colostrums or
mastitis milk.
Procedure:
1. Take 5 ml. of milk in test tube.
2. Add equal quantity of 68% Ethyl alcohol.
3. Mix the contents of the test tube by inverting several times.
4. Examine the tube and note any coagulation.
If coagulation has occurred fine particles of curd will be visible
on the inside surface, presence of flake or curd denotes positive
alcohol test. Such samples are rejected.
9. Sediment Test
Objective:
To know the extent of visible dirt present in the milk as a mark of
clean milk production.
Procedure:
i. Take a milk sample from well stirred can of milk with the help of
sampling dipper.
ii. Filter the milk through properly adjusted firm link disc held in the
sediment tester, so that a filtration area of 28 mm in diameter is
exposed.
iii. Remove the cotton disc from sediment tester after filternation.
iv. Compare the lintine cotton disc with the standard disc as
indicated below.
10. Resazurin Test
Objective:To determine extent of bacteriological quality of milk.
Procedure:
i. Milk the sample thoroughly by inverting from one to another
container.
ii. Pour 10 ml. of milk sample in to previously sterilized test tube.
iii. Add quickly 1 ml. of Resazurin solution in the test tube.
iv. Mix the milk and dye thoroughly by inverting 2-3 times.
v. Place the tubes in the water bath at the temperature of 37.5 0 C
only for two minutes.
vi. The tubes are then removed from the water bath.
vii. Compare the colour to test tube with standard disc until the
colours are matched under comparator.
viii. Record the number of disc/colour of disc. If colour falls
between two disc numbers record half value.
