34 THE MILK QUESTION 



milk also adds its quota. The cleaner the cow the less 

 noticeable the flavor. A stable with a strong ammoniaca! 

 odor of decomposing cow dung is bound to assert itself in 

 the milk. A clean stable or dairy will be free of odors. 

 Many of the volatile flavors and odors in milk, whether 

 normal or abnormal, may be driven off by aeration. This 

 is a very common practice among dairymen. 



Milk absorbs odors and flavors as readily as charcoal. 

 If milk is exposed to tobacco smoke, to fish, to onions, to 

 fruit, etc., it will soon be tainted. Turnips, onions, and 

 other strong tasting substances fed to the cow will be per- 

 ceptible in the milk; beet leaves or malt sprouts give the 

 milk a burnt taste and odor. As an illustration of the great 

 care necessary to keep foreign odors out of the cow barn 

 mention is made of the case in Copenhagen where a dairy 

 was disinfected with carbolic acid and the milk had a dis- 

 tinct carbolic acid taste for five days afterwards. 



Upon standing, milk always develops, sooner or later, 

 a sour, bitter, or putrid flavor. This is due entirely to bac- 

 terial action. In fact, bacteria are the common and also the 

 most important cause of abnormal flavors and odors in 

 milk. A sour taste indicates fermentation of the milk 

 sugar; a bitter taste indicates putrefaction of the proteins. 



The fat in milk has a distinctive taste and aroma, owing 

 to certain fatty acids. This is more apparent in butter, 

 where these substances are in greater concentration. 



Chemical constituents 



The chemical constituents of milk are chiefly water, 

 proteins, fats, sugar, and inorganic salts, each of which 

 will now be discussed separately. 



Water. The chief constituent of milk is water. The milk 

 of almost all animals contains from eighty-six to eighty- 

 eight per cent of water. Some milk has normally more 

 water than other milk. Thus the milk of whales is very 

 concentrated and contains only fifty per cent of water. 



