Deodorizing Milk. 17 



the odors rather than favors it and if the milk could be ex- 

 posed in a vacuum their escape would be more complete and 

 more rapid. 



The escape of the odors from the milk depends upon the 

 rapid motion of the odor molecules in it which forces them 

 to escape whenever they approach the surface with suffi- 

 cient velocity to overcome the surface attraction, and the 

 division of the milk into a large number of small streams 

 increases the chances for the odors to escape in proportion 

 to the increase of the surface. The finer the milk streams, 

 the farther they are apart and the longer the stream is in 

 .falling the more complete will the removal of the odors 

 be. Where there can be a movement of air over the milk 

 surface or among the streams of milk this will favor the 

 removal by carrying the odor molecules away and thus 

 preventing them from re-entering the streams. 



Since the molecular movement is greater the higher the 

 temperature it follows that the deodorizing process should 

 be applied as soon after the drawing of the milk as possi- 

 ble before it has had time to cool and the molecular motion 

 to slow down. 



18. Place For Using the Deodorizer, If the aerator or 

 deodorizer is used in the barn or where there are many ob- 

 jectionable odors it must be remembered that exactly the 

 same conditions which favor the escape of the odors which 

 the milk contains when drawn are the best conditions to 

 permit it to become charged with odors from outside, and 

 hence the deodorizer or aerator should be placed where it 

 is surrounded by a current of pure air. 



19. Cooling Milk. The cooling of milk immediately 

 after it is drawn has a powerful influence in preventing 

 odors from developing in it as a result of the growth of 

 any germs which may have found their way into the milk 

 because the low temperature makes their growth much 

 slower. Cooling, then, is not a deodorizing process but 

 one which prevents the formation of new odors. If, then. 



