DAIRY INSPECTION 187 



milk can be cooled down to 40 F., while with ammonia 

 or brine it can be brought still lower, even to freezing. 1 

 The cooler must be thoroughly cleaned each time it 

 is used, stored in a clean place, and protected from dust 

 while in operation, or the milk will take up large num- 

 bers of bacteria during the process of cooling. When the 

 cooler is not properly used and cared for, it has been 

 found that better results can be obtained by pouring the 

 milk directly into a shipping can and placing the can 

 in cold water, although the temperature is lowered very 

 slowly under these conditions, three to four hours being 

 required for the temperature to fall to 60 F. In some 

 cases it has been found more satisfactory to have the 

 milk taken in cans to the shipping station and to cool 

 it there. When this plan is followed the milk must 

 reach the shipping station during the period the germi- 



1 In the northern part of the United States, about 1% tons 

 of ice will be required each year to cool the milk obtained from 

 each cow, while in the southern states about 2 tons will be 

 necessary, allowing for the waste by melting. A ton of packed 

 ice will occupy 40 to 50 cubic feet of space; 12 inches should 

 be allowed on the sides and bottom for sawdust or other pack- 

 ing material and 3 to 4 feet on top for packing and ventilation. 

 With these figures, the dimensions of an ice house of any ca- 

 pacity desired can be determined. A foot of packing material 

 should be placed under the ice even when the ice house has 

 an earth floor, earth being a fairly good conductor of heat, 

 especially when wet. Water from the melted ice will usually 

 drain off through the soil unless the latter is of clay, in which 

 case it will be necessary to excavate 1 or 2 feet, put in a tile 

 drain, and fill in with gravel or cinders. The pipe supplying 

 water to the milk cooler may be run under the floor of the ice 

 house with advantage. (A number of good plans for building 

 ice houses will be found in the U. S. Department of Agriculture 

 Farmers' Bulletin No. 623.) 



