9 8 



Condensed Milk and Milk Powder 



one-fourth parts of fresh milk to one part of evaporated milk 

 causes the evaporated milk to contain .17 x 2.25 = .38 per cent, lac- 

 tic acid. With this amount of acid acting on the casein, it is not 

 difficult to understand why a coagulum is often formed in the ster- 

 ilizer. While the formation of 

 this coagulum may be partly 

 avoided, under certain conditions 

 it appears in every factory and 

 there are more batches, espe- 

 cially in summer, that come from 

 the sterilizer coagulated than 

 otherwise. 



In this condition the product 

 is not marketable. Some means must be provided, therefore, to break 

 up this curd and reduce the contents of the cans to a smooth, homo- 

 geneous and creamy body. For this purpose a mechanical shaker 

 is used. 



Method of Shaking. — The shaker consists of one or more heavy 

 iron boxes or boxes made of black iron pipes. These boxes are 

 attached to an eccentric. The trays filled with evaporated milk cans 



Fig. 45. Shaker 



Courtesy of Arthur Harris & Co. 



Fig. 46. Shaker 



Courtesy of The Schaefer Mfg. Co. 



are firmly wedged into the shaker. When the shaker is in operation, 

 the cans are shaken back and forth violently, causing the curd in 

 the cans to be broken up. 



Speed of the Shaker. — If the shaker is to perform its work 

 properly, it must have long enough a stroke and run fast enough to 



