14: Introduction. 



10. Foul Odors and Flavors in Dairy Products, Since the 

 commercial value of dairy products is determined in a 

 high degree by their flavors and odors and since these 

 qualities are judged through the sense of smell, which we 

 have seen is so extremely delicate and keen, and since such 

 minute quantities of the odor or flavor producing sub- 

 stances are certain to awaken the undesirable impressions, 

 it is clear that the greatest of care must be exercised in 

 producing, handling and caring for them through all the 

 steps preceding the delivery to the consumer. Since we 

 have seen that so little fertilizer may be disseminated 

 through so much soil moisture and since so little may be de- 

 tected by the organs of smell, it is plain that too great care 

 cannot be taken in keeping the milk clean and that only 

 those who do this can hope to secure the custom of people 

 willing to pay a high price for the milk, cream, butter or 

 cheese which just suits them. 



11. How Odors and Flavors Find Their Way Into Milk, 

 The substances producing these qualities in milk make 

 their entrance there in three different ways: (1) from the 

 blood at the time the milk is secreted ; (2) from the outside 

 after the milk is drawn; and (3) they are produced within 

 the milk after it has been secreted before or after it is 

 drawn. 



12. Odors Entering Milk During Secretion, Any volatile 

 principle which may chance to be present in the blood of 

 the animal at the time the milk is being drawn will find 

 its way into the milk and will impart a quality to it, the 

 intensity of the flavor or odor depending upon the amount 

 of the volatile principle present and the readiness with 

 which it evaporates. 



Nearly all food stuffs contain substances which produce 

 odors and if these substances are not destroyed during the 

 processes of digestion they will again escape from the body 

 of the animal through the channels of excretion; that is, 

 through the skin, kidneys, lungs, rectum or udder, and if 



