160 



EVAPORATED MILK SHAKING 



Tig. 68. Evaporated milk shaker 



Courtesy of Arthur Harris & Co. 



tion, the lower the temperature required to precipitate the 

 casein. It seems that the concentration of the milk intensifies 

 the properties of milk to coagulate when subjected to heat. This 

 factor is probably in part at least due to the increase of the per 

 cent of lactic acid in the evaporated milk, due to the concentra- 

 tion. If the fresh milk contains .17 per cent lactic acid, a con- 

 centration of two and 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 lactic acid. With this amount of acid 

 acting on the casein, it is not difficult to understand why a coag- 

 ulum is often formed in the 

 sterilizer. While the formation 

 of this coagulum may be partly 

 avoided, under certain condi- 

 tions it appears in every fac- 

 tory and there are more batch- 

 es, especially in summer, that 

 come from the sterilizer coag- 

 ulated 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, homogeneous 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 iron crates made of black iron pipes. These 

 boxes are at- 

 tached to an 

 eccentric. The 

 trays filled 

 with evaporat- 

 ed milk cans 

 are firmly 

 wedged into 

 these b o x e s. 

 When the 

 shaker is in 

 operation, the 



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

 the cans to be broken up. 



Fig. 69. Evaporated milk shaker 

 Courtesy of The Engineering Co. 



