278 MANUFACTURE: OF MILK POWDER 



Annual Production of Skim Milk Powder, Whole Milk Powder 

 and Cream Powder in the United States. 1 



According to Potts, 2 the number of firms manufacturing 

 powdered milk products in the United States is as follows: 



Skim milk powder ^7 



Whole milk powder 15 



Cream powder 3 



Description of the Principal Processes of Manufacture. 



The processes of desiccating milk, which have proven com- 

 mercially successful and have found wide application, may be 

 conveniently grouped into three fundamental categories, accord- 

 ing to the predominating principle upon which they are based. 

 These are : 



1. Dough-drying processes. 



2. Film-drying processes. 



3. Spray-drying processes. 



For detailed discussion of the more outstanding principles 

 covered in some of the patents of these processes the reader is 

 referred to the following brief description and illustrations. 



1. Dough-drying Processes. 



To this group largely belong the earlier and cruder pro- 

 cesses. The milk is condensed in any manner, either by heating 

 in open pans under atmospheric pressure and usually with the 

 help of mechanical agitation ; or in the vacuum pan with or with- 

 out mechanical agitation; or in open vats by blowing heated 

 air through the milk, to a high degree of concentration and to 

 a dough-like consistency. The concentrated product is then 



1 The Market Reporter, U. S. Bureau of Markets, Vol. I., No. 14, 1920. 

 9 Potts. Data furnished by correspondence. 1920. 



