120 



EvAPOKATi'D Milk — Sterilizing 



CHArTER XL 



STERILIZING 



The sealed cans are now ready fiir the sterilizer. ]f tliey 

 cannot be sterilized within an hour or two they should be sub- 

 merged in ice water or ])laced in a refrigerating room until the 

 sterilizer is ready for them. This precaution is especially ad- 

 \isahle in summer. 



Purpose of Sterilization. — The chief pur])ose of subjecting 

 the e\-aporated milk to the sterilizing process is to kill all germ 

 life and, therefore preser\'e the product permaneiitly. AMien the 

 hermeticalh' sealed cans come from the sealing room, their 

 contents are not sterile. The oniv means to preserve this milk 

 is to subject it to temperatures high enough to kill all forms of 

 ferments, organized and unorganized, vegetatix'e cells and spores. 

 The success of the manufacture of this product depends to a 

 large extent on the process of sterilization. 



Aside from this, the manufacturer aims to gain another com- 

 mercially important condition, namely, to prevent the separation 

 of the butter fat. ISefore sterilization, there is nothing to prevent 

 the fat from separating out in the e\'aporated milk and from 

 churning in trans])ortation, unless the evaporated milk was 

 homogenized. This is a highly undesirable characteristic, mak- 

 ing the gocids unmarketaljle. The sterilizing process helps to so 

 change the ph3'sical properties of the milk, that this tendency 

 of the fat to separate is greatly minimized. The sterilizing 

 temperatures used, further lend to the evaporated milk a creamy 

 consistency and yellowish color, gi\"ing the product a semblance 

 of richness. 



Sterilizers. — The predomi- 

 nating apparatus used for ster- 

 ilizing is a huge, boiler-like, 

 hollow, iron cylinder or box. 

 It opens either at one end 

 or on the side. Its interior 

 is equipped with a re\-olving 

 framework, steam inlet and ex- 

 haust, a water distributing pij^e 

 running the entire length of 



Fig. 45. Sterilizer for evaporated mill<. 



Courtesy ol Arthur Harris & Co. 



