Milk Testing – Sediment Test
Objective:
To know the extent of visible dirt present in the milk as a mark of clean milk production.
Relevant Information:
Sediment test of raw milk will reveal the extent to which visible insoluble matter has gained entrance in the milk. It is a rapid test indication quantitative measure of carelessness in handling the milk and lack of sanitation. But in milk that appears as visible or insoluble sediment is always associated with relative amount of microbes. The test is carried out by allowing a measured quantity of milk to pass through a fixed area of a filter disc and comparing the sediment with the prescribed standards.
Precautions:
1. Row milk should be tested.
2. Curdled milk should be separated.
3. Temperature of milk while receiving at milk plant should be 5 0 C.
Material Required: Milk
Apparatus:
i. Sediment tester:This apparatus consists of a bottle open at both ends. To the neck of which is fastened a clip and wire guage. This inverted neck is kept downwards in stand small cotton discs are used to retain the dirt.
ii. Lintine disc 32 mm in diameter.
iii. Sampling dipper of 500 ml. capacity.
iv. Sediment disc ratings: 0.0, 0.2, 0.5, 1.0, 2.0 mg sediment per 500 ml. of milk.
v. Sieves
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.