240 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



AERATING THE MILK. 



Aeration of milk is its exposure to the air for the purpose of 

 removing * 'animal odor" or other taint. It is generally regarded 

 by milk shippers and other handlers of milk as a useful opera- 

 tion. The benefit derived from aeration depends on how much 

 the milk is tainted or "off." The product of a healthy cow, 

 obtained with due regard to cleanliness and feeding, has little or 

 none of the "cowy" odor. But it is difBerent when the cow is 

 slightly out of condition, is illy kept, or has been given some 

 strongly smelling food previous to milking; then aeration has a 

 beneficial effect, and although the taint is not entirely removed, 

 it is reduced. It is of use chiefly in removing odors absorbed 

 from the air or from food eaten by the cow; both these are the 

 strongest when the milk is first drawn, while those caused by 

 bacteria are least noticeable when the milk is fresh, and increase 

 when it is held. 



Milk is said to be "smothered" when it is tightly closed in a 

 can immediately after milking, without cooling or the removal 

 of gases which it contains. When thus treated it soon becomes 

 unfit for use. Cans with holes in their lids are used to prevent 

 this trouble, but ventilation is unnecessary if aeration is practiced. 

 All taint should be out of the milk before the lid is put in place. 



Aerating does not have a marked effect on the keeping quality 

 of milk; its benefit is in removing undesirable odors. Some 

 persons of sensitive taste can not drink unaerated milk, but relish 

 it when aerated. Tne operation is done with varying success in 

 several different ways. Usually the milk is cooled more or less 

 at the same time it is being aerated, and it is due to this that its 

 souring is retarded. Actively stirring or agitating milk serves to 

 partially aerate it, and this should always be done if arrange- 

 ments for more thorough work are not at hand. A better 

 method is to dip from the can a few quarts and pour it back 

 slowly from a height. This should be repeated many times, de- 

 pending upon how much taint there is and the quantity of milk; 

 or the milk may be poured from one vessel to another with the 

 same effect. Still more thorough work is accomplished by al- 



