COMPOSITION OF MILK
Milk is the normal mammary secretion derived from complete milking of healthy milk animals. It should be free from colostrums. The presence of all the nutrients in the milk makes it an ideal and complete food. Major constituent of milk are water, lipids, carbohydrates, proteins and minerals. The other are present in low concentration but are vital to human beings.
Considering the health of consumers and as per FSSAI rules Union is striving in providing quality MILK and Milk Products to consumer. The Quality of milk is being maintained by using state of the Art Technology and testing Mechanisms. The Union has Laboratory with required facilities for the analysis of milk and products, Ingredients as per the procedure. The Laboratory is also equipped with packing materials used for milk and milk products. The Union ensures to comply with GMP & GHP practices relevant to the Industry at different level of processing enable us to strengthen the Quality management system.
SAMPLING OF MILK:
After thorough mixing a representative of the entire batch of milk is taken for analysis. The method of mixing of milk is differs depending on the container from which milk is taken for analysis.
- ORGANOLEPTIC TEST:
This is the basic tool test for milk at the stage of receiving at Dairy /CC. The human organ – Noise & Eye is used to look into any difference in color of milk, presence of extraneous matter. If there is no problem then the milk is passed for acceptance otherwise i.e Milk having foul or abnormal smell or flavor and any abnormal will be deviated as rejected or COB as per the accurance.
- CLOT ON BOILING
This is a quick test to determine on feasibility and the suitability of milk for processing. Clotting of milk on the sides of the test tube or at the bottom indicates poor keeping quality and developed acidity above 0.17%. Such milk will not withstand pasteurization where milk is heated to 72.6?C and held at that temperature for 15 sec.
- SEDIMENT TEST
Sediment test is used as a quantitative measure of indicating the cleanliness of milk with respect to invisible dirt and dust particles in milk.
- ALCOHOL TEST
This test is used for rapid assessment of stability of milk for advanced heat processing, particularly for condensation and sterilization. The test aids in detecting abnormal milk such as colostrums, late lactation milk, milk from animals suffering from mastitis and milk in which the mineral balance has been disturbed.
Although titrable acidity is not a true measure of lactic acid present in the milk, it reflects the acidity produced in the milk as a result of bacterial action. Hence, titrable acidity is employed to ascertain the keeping quality and suitability of milk for heat processing.
- DETERMINATION OF ADULTERANTS
The modus of operand of scrupulous elements among products/severs are many to cheat the Dairy Co-Operative Society, general public at large. The Union has well equipped laboratory to plug such inflows to Union by having suitable testing mechanisms at Dairy Co-Operatives levels, BMC, CC and all processing units. By having this facility it strives to supply quality milk and Dairy products to the best satisfaction of general public at large and NANDINI consumers.
- DETERMINATION OF FAT
Commercial value of milk is largely based on its fat content. Therefore, determination of fat content of the milk has special significance in the evaluation of quality of milk. Butyrometric methods are employed for the rapid and routine determination of fat in milk. The commonly used Gerber Butyrometric method depending on the liberation of the fat by the action of sulphuric acid on milk in butyrometer which are then centrifuged to aid the separation of fat.
- ESTIMATION OF SNF
Though gravimetric method is the standard method of estimation of total solids and solids not fat it is not possible to follow this considering the time consumption on routine basis. Where number of samples to be analyzed are many. The estimation of total solids and SNF are generally done by determining the specific gravity of milk with a lactometer, the fat by Gerber method and employing a formula involving specific gravity, fat and constant factor. Presently we are following the 2 stage BIS formula to assess SNF/TS contents very nearer to gravimetric method of estimation. The formula is
SNF = (CLR/4) +0.25 X Fat% +0.35
MICROBIOLOGICAL ANALYSIS OF MILK
- METHYLENE BLUE REDUCTION TEST
This test is carried out for both raw and pasteurized milk. The time required to reduce the color of the dye methylene blue by the milk sample indicates the microbial load present in that sample. The change in the color appears because the bacteria present in the milk ferment the milk sugar.
- PHOSPHATASE TEST
This test is carried out for pasteurized milk to see the efficiency of pasteurization. This test is done to determine the milk has been heated adequately during the pasteurization process or not? It is based on the concept that phosphatase is an enzyme which liberates inorganic phosphate from organic compounds which contains phosphates in an ester linkage.
- STANDARD PLATE COUNT
Bacterial count of the milk sample can be estimated by standard plate count technique, this enable us the number of colony forming unit per ml of milk. The clean milk will have very low microbial count than that of collected or handled under unsanitary conditions or improperly refrigerated.