242 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



filthy surroundings where the milking is done. Aeration is a 

 means of only in part overcoming these neglects. 



COOLING OF MILK. 



When milk is for cheese or butter making and is to be soon 

 used or promptly delivered at the factory, it may be cooled 

 sufficiently by thorough aeration on the farm. But if it is not at 

 once hauled away or is not to be immediately separated or set 

 for cream, or must be carried a long distance, or is to be used in 

 its natural form as food, fermentation must be checked by low 

 temperature. Cooling is the only important operation in the 

 dairy which should ever be modified, and then only under the 

 conditions named. It is often stated that milk does not require 

 so much care when it is to be used for butter or cheese making 

 as when it is to be sold at retail. This is true in a way, only as 

 far as the cooling is concerned, and it is very misleading. First 

 €lass butter or cheese can not be made from inferior milk; for 

 ^the factory, milk should be drawn and handled with all the pre- 

 ^cautions against contamination, the same as if it were to be sold 

 ;at retail; but it need not be held at a temperature so low that 

 "the germs of lactic acid can not increase. A certain amount of 

 acidity is necessary for cheese or butter making, and this may 

 ^be allowed to partially develop in the milk before it leaves the 

 farm without harm to the product. Some cheese makers prefer 

 that the temperature never be allowed to -go below 60 degrees F. 



The lower the temperature to which milk is cooled and held, 



the longer it can be kept in good condition. It is the custom of 



; some dairymen to serve their customers soon after milking and 



without first cooling the milk. In such cases it is impossible for 



it to long remain sweet, and within a few hours it undergoes 



:more change than milk usually sold in cities; this is because the 



j latter was promptly cooled and kept cold, although it may have 



Ibeen one or two days old when delivered. 



It is hardly necessary to emphasize the importance of prompt 

 and rapid cooling when the rate at which germs multiply in warm 

 milk is understood. The milk from one cow should be cooled 



