MILK SUPPLY AND CREAMERY PRODUCTS 51 



ing melted butter-fat or oil mixed with water or skim 

 milk through exceedingly small apertures under high 

 pressure, or otherwise breaking up the mixture, an 

 emulsion can be formed in which the fat globules are 

 much finer even than those in natural milk or cream, 

 and separation can be prevented. The force used in 

 these emulsifiers may be produced by powerful pumps, 

 or a steam jet, or centrifugal force under high speed; 

 whichever system is used the machines answer the same 

 purpose, to produce a permanent emulsion in which the 

 oil or fat will stay in suspension even after cooling. In 

 some milk supply plants and ice cream factories all the 

 cream is emulsified and the system has especially been 

 applied since the advent of the milk powder. It is now 

 a not infrequent practice to run the new milk through 

 the separator, make sweet, unsalted butter from the 

 cream, and milk powder from the skim milk, and to 

 ship or store these products separately where or until 

 cream is wanted and then bring them together again 

 by running them through the emulsifier with a suitable 

 amount of water. At first thought this process would 

 seem impractical and imeconomical. But it has proven 

 good business because in many cases and places skim 

 milk powder and butter keep better separately or can 

 be shipped at long distance to better advantage than 

 new milk or cream or condensed milk. In ice cream 

 factories business may be dull in cold weather and 

 cream is perhaps not provided and not available, when 

 suddenly a hot spell brings orders for large quantities. 

 With a stock of skim milk powder and butter on hand 

 in the refrigerator, and an emulsifier to mix these 

 products, cream can be produced on short notice and 

 there will be no danger of shortage. 



