DAIRYING 21 



698. Aeration of milk is not necessary if the milk is clean 

 and the cooling can be done without it. Milk or cream should be 

 exposed as little as possible to dusty air. Sudden cooling and 

 holding at a cold temperature is the most satisfactory way of 

 keeping milk sweet. 



Cooling is the only milk preservative that is permitted by 

 law in some states ; the chemicals advertised for this purpose are 

 injurious to the consumer's health and the addition of them to 

 the milk, cream or butter is forbidden. 



Never pour warm milk into cold. Do not mix the two lots 

 until both are near the same temperature. 



ODORS IN MILK. 



699. The common odors in milk may be divided into two 

 classes: First, those that can be removed by aeration. These 

 are absorbed from the surrounding air after milking and include 

 such odors as barny or stable odors, cowey, kitchen and silage 

 odors. 



To the second class belong the odors that cannot be removed 

 by aeration. These come from the feed eaten, such as wild 

 onions, weeds, turnips and too much new pasture grass, which 

 latter gives an unpleasant flavor to butter during the first days 

 of changing from stable to pasture feed. This soon passes away, 

 however, when the cow's digestive system gets adjusted to the 

 sudden change. 



700. The feeding of silage to cows does not necessarily con- 

 taminate the milk. Sufficient proof of this is the fact that silage 

 is being constantly fed to cows that are producing some of the 

 highest priced milk in the country and milk which is much 

 sought for by physicians for the use of invalids and hospitals 

 because of its purity and wholesome flavor. 



The objection to silage feeding in the majority of cases 

 comes from the poorly ventilated stables. Milk will absorb the 

 silage odor if it is present in the barn and for this reason it is 

 necessary to have the silo closed except when silage is being 



