278 MANUFACTURE oF MiLk PowbER 
Annual Production of Skim Milk Powder, Whole Milk Powder 
and Cream Powder in the United States.' 
Pounds by Years 
Kind of Product 
1918 1919 
Skim milk powder ................ 25,432,007 33,076,131 
Whole milk powder............... 4,164,334 8,660,785 
Cream powder (nescce scenes ken s 654,360 992,070 © 
According to Potts,? the number of firms manufacturing 
powdered milk products in the United States is as follows: 
Sleim -1itilke Ow rs wid Gas otaedee ad oes Gens 47 
Whole milk “powders. seuss wnewen se date oe 15 
Crean: pOwdGe ie ee er eye ae aa ee 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 m 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 
1The Market Reporter, U. S. Bureau of Markets, Vol. I., No. 14, 1920, 
2Potts. Data furnished by correspondence. 1920. 
