Processing of milk and milk products.pptx

Processing of milk and milk products

1. welcome

2. Experimental learning programme (ELP) 2022 Course no. - ELM AHDS 486 Course tittle –   Processing of milk and milk products Mahatma Phule Krishi Vidyapith,  Rahuri Afiliated  

3. Quality analysis of raw milk Platform tests Aim : F or examination of milk by adopting rapid test for acceptance / rejection of incoming milk. Platform test includes = Organoleptic evaluation Clot on boiling test Alcohol test Resazurin test Sediment test

4. A) ORGANOLEPTIC EVALUATION : Organoleptic evaluation consist of following aspects = i)Odour/Smell – Remove the lid of can hold it inverted and raised to the nose and inhale for the smell. Record the odour/smell as normal or abnormal. Normal milk has pleasant, sweetish smell. ii) General appearance – Note whether the milk is clear or any visible dirt or foreign matter has grained entrance in milk. If so, describe its nature for detecting the amount of dirt in the milk, conduct the sediment test if necessary.

5. iii) Colour: observe the colour of milk as white, light yellow. Record wether the colour of milk is normal or abnormal i.e. abnormal colour’s are reddish, bloody, bluish etc. iv) Consistency : Record the consistency of milk as normal, watery, thick, ropy, slimy, etc.

6. B. CLOT ON BOILING TEST PROCEDURE – Transfer 5.0 ml of milk in a 20 ml test tube using graduated pipette. Place the tube in boiling water bath for five minutes. Alternatively , hold the tube over a flame and allow the contents to boil. Observe formation of clots or lakes on the test tube wall. Formation of flakes or clots indicates positive test .

7. C. ALCOHOL TEST PROCEDURE : Transfer of 5 ml of milk in test tube using graduated pipette. Add equal of ethyl alcohol. Close the mouth of the test tube with thumb and mix the content well by inverting the test tube several times. Observe for formation of any flakes on the wall of the test tube. Present of flakes shows positive test.

8. D. TEN MINUTES RESAZURIN TEST PROCEDURE- Mix the sample thoroughly. Pour the 10 ml milk sample into previously sterilized test tube. Add quickly 1 ml of resazurin solution in the test tube and mix the milk & dye by inverting 2-3 times. Place the test tube in water bath at the temperature of 37.5 0c for 10 minutes. The tube is then removed from the water bath. Compare the colour of test tube with standard disc until the colour’s are matched under comparator. Record the number of disc/ colour of disc. If colour falls between two disc numbers record half value.

9. E. SEDIMENT TEST PEOCEDURE – Assemble the off-bottom sediment tester, for cans and tankers by inserting sediment disc 1n the space provided. Dip the tester to the bottom of the can without disturbing the milk. Collect milk slowly from different parts of can bottom by pulling the plunger upwards. Lift the sediment tester and press the plunger down and empty the tester. Dismantles the sediment tester and remove sediment disc carefully. Compare with standard sediment disc or weigh the disc. Grade milk in accordance to ISI standard. In case if mixed sample sediment tester pass 500 ml milk through the tester.

10. SPECIFIC GRAVITY, SNF OF MILK Aim : To determine the basic nature of milk and to decide the nature of adulteration of milk.

11. Material Required : Whole milk, skim milk, partially adulterated milk Apparatus : Lactometer, jar, petri dish, dairy floating thermometer, beakers

12. PRECAUTION The milk to be tested should be 2;3 hours after milking. Adjust the temperature of milk to

13. Procedure : Adjust the temp. of milk sample to measuring temp. prescribed for lactometer ( 27 O c) Mix the sample well avoiding incorporation of air or foam formation. Pour sufficient milk into the glass or steel cylinder to allow free floating of lactometer. Place the lactometer in the milk and allow it to float till it stops. Record the lactometer reading and temperature of milk at the same time. Take another reading by flopping by flapping top of lactometer stem and when it again assumes constant level. Take average of the two readings. Get corrected lactometer reading/ value ( CLR) from the standard table for corresponding temperature.