22 DAIRY LABORATORY GUIDE 



c.c. alkali 34 X .009 ^. .^ „^„„ . , 

 50 c.c. Cream X 1 00 = .612% acid. 



Obtain by means of a pipette a sample of milk 

 from the top and one from the bottom of a beaker 

 of milk that has been allowed to stand for several 

 minutes. Test and note difference. Why? 



Farrington's Alkaline Test 



Dissolve five of Farrington's tablets in enough 

 water to make solution 97 c.c. Mix well and measure 

 out 17.6 c.c. of the milk or cream to be tested, and 

 add the alkali solution as in previous tests until the 

 characteristic pink color remains. The number of 

 c.c. of alkali solution required to produce this result 

 indicates the number of hundredths per cent acid, - 

 since 1 c.c. of alkali neutralizes .01 per cent of acid 

 when 17.6 c.c. of milk are used. Therefore the 

 number of c.c. neutralizer used divided by 100 

 equals per cent of acid. For instance: If 50 c.c. 

 solution be used the acidity of the milk in question 

 is .5 per cent. The Farrington tablets contain alkali 

 equal to 3.8 c.c. of tenth normal solution and also 

 the color indicator. 



Van Norman's Alkaline Test 



Pour into a 1000 c.c. graduated flask 20 c.c. of 

 normal caustic soda (NaOH) solution, fill to the 

 1000 c.c. mark with distilled water, making 50th 

 normal alkali solution. Put 17.6 c.c. of milk or 

 cream to be tested into a beaker and add four to 



