84 QUESTIONS AND ANSWERS 



What causes the color of the milk to change in the 

 tests for heated milk? 



The enzymes of the milk set free oxygen from 

 the hydrogen peroxid and the free oxygen sets 

 free iodine from the potassium iodid. Then the 

 free iodine colors the starch blue. When the 

 enzymes are destroyed by heat no action takes 

 place and the milk remains white. 



In the second test the oxygen, set free by the 

 enzymes, acts upon the other reagent, causing it to 

 change to a blue color. 



What are the common ways of adulterating cream? 



1. By diluting the cream with milk. 



2. By the addition of thickeners. 



3. By the addition of preservatives. 



4. By the addition of acid neutralizers. 



How may the tendency to dilute the cream be over- 

 come? 

 By buying and selling cream upon the basis of 

 the fat content. 



How may the presence of condensed milk or con- 

 densed skim milk in cream be detected? 



Separate the fat of the cream from the serum. 

 Determine the per cent of solids not fat in the 

 serum. If the serum contains a greater percentage 

 of milk solids not fat than is found in skim milk, 

 the presence of condensed milk or condensed skim 

 milk is assured. 



How may the presence of gelatin in cream be de- 

 tected? 



