MILK POWDERS. 



21)1 



5 volumes of water does the food value approximate to that of 

 human milk ; it is doubtful, however, whether fat can be replaced 

 entirely by cane sugar, especially for young infants. 



Milk Powders. — There are several methods of preparing milk 

 powders ; in the .Just-Hatmaker process the milk is evaporated 

 on rollers heated by high-pressure steam above the temperature 

 of boiling water, and the dried layer of milk is continuously 

 taken off by a knife set at a suitable angle. Other processes 

 employ evaporation on rollers or discs heated to a lower tem- 

 perature in vacuo, and the milk is preferably previously con- 

 centrated in a vacuum pan to one-third of its bulk. The milk 

 may also, after preliminary concentration, be dried in shallow 

 trays in vncun, or on bands of wire gauze or other material. 

 Another excellent method is to atomise the milk by spraying, 

 and to evaporate this in a current of hot air. 



In order to ensure that the milk powder is soluble in water, 

 a small amount of an alkali — sodium carbonate, sodium phos- 

 phate, or saccharate of lime — is smnetinics added. To prevent a 

 separation of the fat in large particles on remixing the milk 

 powder, the milk is often homogenised before drying ; this has 

 the further advantage that the fat has less tendency to become 

 rancid. 



The table below f^ivcs the analysis of seven samples : — 



TABLE LIII. — Composition ok .Milk Phwiikhs. 



