CHAPTER III. 

 Testing Milk and Cream. 



17. Temperature of sulphuric acid and mUk. The 



temperature of the acid and milk should be about 

 the same — preferably between 60° — 70° F. When 

 the acid has a tempei'ature of 65° P. and the tem- 

 perature of the milk is below 55° F., add a trifle 

 more acid; and when the milk is above 75° F., add 

 a trifle less acid. The reason for this is that the 

 acid produces a certain amount of heat in the milk, 

 which is necessary to produce a complete digestion 

 of casein in the milk, in order to liberate the fat. 

 Improper temperatures of either the acid or the 

 milk, or both, is a frequent cause of a cloudy, flaky 

 or charred fat column, and black or white specks in 

 both milk or cream tests. 



18. Measuring milk into the test bottle. Use a 

 17.6 c.c. pipette; fill up to the mark on the stem 

 of the pipette. Place the point of the pipette in 

 the mouth of the test bottle, and hold both the pi- 

 pette and the test bottle in an inclined position. 

 This allows the iliilk to run down the inside of the 

 neck of the bottle, and avoids spilling the same. 

 When the milk is all out of the pipette, blow through 

 it gently in order that any drops adhering to the in- 

 side of it may drop into the bottle. 



19. The mixing of milk and acid. AVhatever acid 

 measure is used in measuring the acid into the test 

 bottle, the bottle must be held in an inclined posi- 

 tion, so that the acid may run down on the inside 



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