UNSWEETENED CONDENSED MILK DEFECTS 221 



Effect of Superheating. The superheating of the milk before 

 sterilization and the stopping of the reel of the sterilizer as ex- 

 plained under "Sterilization," page 120, also tend to so increase 

 the viscosity of the evaporated milk as to minimize its tendency 

 to separate its fat. But here again good judgment is required, 

 otherwise there is danger of spontaneous thickening of the prod- 

 uct after manufacture. 



Turning the Cans in Storage. Many manufacturers, in an 

 effort to avoid fat separation, have adopted the practice of turn- 

 ing their goods in storage at regular intervals. This operation 

 naturally interferes with and retards the rising of the fat to the 

 surface, as long as the goods remain in the factory. After they 

 leave the factory this control must of necessity cease and if the 

 evaporated milk, owing to the process of manufacture and the 

 condition of the product, is destined to separate its fat, the turn- 

 ing of the cases, while at the factory, cannot permanently prevent 

 separation. Where the goods are consumed immediately after 

 they leave the factory, this practice may serve the purpose ; but, 

 since the large bulk of evaporated milk manufactured, is exposed 

 to prolonged storage, its advantage is very limited. 



Effect of Homogenizing. Under average conditions careful 

 attention to the precautions above discussed will greatly mini- 

 mize and often prevent fat separation. At best, however, much 

 of the evaporated milk on the market shows signs of separation 

 after sixty to ninety days and some of it even after two weeks, 

 for the fundamental cause of separation, the difference in gravity 

 between the fat globules and the rest of the milk constituents, 

 is still present; then again, under less favorable conditions, even 

 the above precautions may not prove adequate to keep the fat 

 from separating. 



The introduction of any agent or process, therefore, capable 

 of permanently removing this fundamental cause, must prove 

 a lasting benefit to the manufacturer of evaporated milk. This 

 agent has been found in the homogenizer. The homogenizer 

 makes it possible to divide the fat globules so finely, that their 

 buoyancy or gravity force is not great enough to overcome the 

 resistance of the surrounding liquid. They are unable to rise to 

 the surface, but remain in homogeneous emulsion. 



It is quite probable that aside from the reduction of the size 



