'38 'Condensed Miek'and Milk Powder 



Solution of Sucrose. — It is very essential that all the cane su- 

 gar which is added to the milk, he completely dissolved, in order to 

 lessen the tendency of the sugar to crystallize in the finished prod- 

 uct. Undissolved sugar crystals in condensed milk, act in a physical 

 way much as bacteria in fluid milk do in a bacteriological way. They 

 multiply rapidly, and such condensed milk usually precipitates its 

 sugar before the product- reaches the market. The presence of ex- 

 cessive sugar crystals makes the product gritty and causes the for- 

 mation of a sediment in the bottom of the cans; this is objectionable 

 to the consumer. When the milk is heated to the proper tempera- 

 ture before condensing, the solution of the cane sugar is facilitated 

 and the tendency toward grittiness is minimized. 



Prevention of Burning Miek on Heating Surface. — If cold 

 milk comes in contact with a steam-heated surface and is not agi- 

 tated vigorously, it bakes or burns onto this heating surface. The 

 milk in the vacuum pan is heated or kept hot by means of the steam 

 jacket and coils. These radiators are charged with steam under 

 pressure arid consequently give off a high degree of heat. If cold 

 milk is drawn into the vacuum pan, the milk remains calm for a 

 considerable length of time. During this time it is bound to bake 

 or burn on the heating surface, giving the product a burnt flavor, 

 causing it to contain brown specks and retarding the process of 

 evaporation. If the milk is hot when it enters the pan, the reduced 

 pressure in the pan causes it to boil violently at once, avoiding all 

 danger of sticking to and burning on the heating surface. 



Temperature. — In most factories the milk is heated to from 

 1 80 degrees F. to 200 degrees F. This temperature is sufficient to 

 accomplish the three purposes. Heating the milk to the boiling point 

 tends to give it a rather pronounced cooked flavor, which is objec- 

 tionable. However, in the case of danger of contamination of the 

 milk with resistant types of undesirable bacteria, it may become nec- 

 essary to practice boiling the milk. 



Manner of Heating. — Thorough, efficient and rapid heating 

 of large volumes of milk to temperatures near the boiling point is a 

 problem that requires careful consideration. The tendency of the 

 milk to stick to the heating surface is a permanent obstacle and ef- 

 forts to overcome this frequently result in sacrificing thoroughness 

 of heating. 



