LPT 311: Milk and Milk Products Technology (1+1)

COMPOSITE SAMPLES

• Composite milk sample is one which when properly prepared represents two or more lots of milk. When payments are made according to quality and not the quantity, quality control tests are conducted in composite samples to reduce the cost and labor.
• Composite sample is prepared by taking an adequate portion depending on the quantity of milk from the source for a period of several days. Sample is properly bottled, labeled and tested after a week.
• The results got from composite sampling, give an average value for the total amount of milk received during the period covered. This is an accurate simple system by which labour and time are saved.
• The jar used to prepare the composite sample should be air tight to prevent evaporation of moisture. Rubber corks are prepared. Composite samples must be kept in a cool place to minimize the possible amount of preservatives.
• The contents of the jar must be mixed by a gentle rotation every time a daily sample is added. If the sample shows any churned cream, the sample should be warmed to 105^ºF to 110^ºF before addition.
• Since the composite samples must be kept for longer periods, preservatives are used. Preservatives are placed in required quantity in the empty bottle before the milk is added.  
• The following records should accompany the sample
• Time and date of sampling
• Products
• Temperature of product(s) sampled
• Location sampling took place
• Interim transport details if any
• Samplers name and identifier