Method of Sampling of milk which is contained in one vessel

METHOD OF SAMPLING OF MILK

  • Due to the difference in specific gravity between the milk serum and fat of the milk, the fat globules are continuously rising towards the surface of milk. So mixing is essential to make it uniform through out. If the milk is of little quantity, by pouring from the one pail to other, mixing can be done. When larger volumes of milk are handled plungers are used to mix it effectively, by moving the same up and down for not less than ten times.
  • Another type of plunger (two pounds of weight), which is attached by means of long linked chain, is also used. Any type of plunger, used, should be sterilized properly. Every time, before using for a container, plunger is sterilized in antiseptic solutions.
  • After through mixing, usually 100-150 ml of milk is taken by means of the dipper and is transferred to a sample bottle, which is later corked tightly by a rubber stopper. Glass stoppers will not close the bottle tightly. Cork stoppers absorb fats from samples. They cannot be sterilized; they get cracked during the process. So the rubber stopper, which is free from the above two defects is most preferred.
  • Bottles are filled leaving a space ¾ inches at the top. If it is half filled, there is the risk of churning during the transit. If it is filled full, there is no room for efficient mixing by shaking.
  • The shape of the bottle is also important. Bottles with out ankles, where there is a chance for lodgment of no solids are preferred. It is desirable that the bottle be provided with a ground area for detailed labeling. One or two sample sites in a bigger lot are preferred for accurate results. Sampling should be done at a temperature between 60-90ºF (15.7ºC to 32.3ºC).
Last modified: Friday, 18 February 2011, 4:35 AM