ILLINOIS DAIRYMEN'S ASSOCIATION. 2IQ 



apparently Again heat that milk to the temperature of the body and the 

 animal odor will reappear. This demonstrates, therefore, that the animal 

 odor was not eliminated, but that the cooling process caused it to appar- 

 ently disappear. It is also true that if we desire to obtain the gases from 

 milk, these gases can most easily be secured by warming the milk. In 

 fact, if we boil the milk, we can drive off most of the gases. Therefore, if 

 we were going to eliminate gases from the milk, it is far more desirable 

 to aerate when the milk is warm and it would not be a logical method 

 T>y any means to combine aeration and cooling and make them a simulta- 

 neous process. The time, .therefore, for aerating is immediately after 

 milking and before cooling. 



It may be said in passing, that although it is very difficult to demon- 

 strate, it is probably true that the presence of a considerable amount of 

 carbon dioxide in the milk influences the character of the fermentation. 

 It seems to be an established fact that where only traces of oxygen exist 

 poisons are more likely to be formed in food substances. It is note- 

 worthy in connection with milk that there are several cases of poisoning 

 on record where the milk had not been aerated, had been shut up In 

 cans, the air excluded, the temperature high, and all those conditions 

 present which are usually regarded as unfavorable. To illustrate this 

 more thoroughly, you shut up a ten gallon can of milk, leaving only a small 

 air space at the top, it will be found that soon all the oxygen in that arr 

 space is rapidly consumed and carbon dioxide given off. It follows, under 

 such conditions that we have established the most favorable environment 

 for the development of an aerobic bacteria, which would not grow rapidly 

 if they were transferred to an abundant supply of oxygen, lower tempera- 

 tures, and other circumstances which we usually find where milk is 

 properly handled. 



We may claim, therefore, for aeration considerable of practical import. 

 It fosters the desirable fermentations by creating a larger supply of 

 oxygen and by reducing the amount of carbon dioxide. It eliminates 

 those gases which are not considered desirable and which are frequently 

 mentioned as animal odors, taints, etc. It is quite likely that it checks 

 the development of those micro-organisms which produce poisons. 



4. The Temperature of Milk. — The value of cooling milk is doubtless 

 already known to you all. It is not especially necessary that I should 



