134 EVAPORATED MILK SEALING 



at the proper temperature at the time of filling. Experience has 

 shown that warm milk, or milk with a temperature above about 

 60 degrees F. causes more trouble in this respect than cold 

 milk. 



With the rapid and general adoption and use among con- 

 denseries of a cold storage system, the evaporated milk usually 

 has a temperature between 40 and 50 degrees F., when it reaches 

 the filler, and at these temperatures the tendency to foam is 

 reduced to such an extent that the filling can be done without 

 interference or interruption due to foam. 



In order to economize both space and time, it has been 

 found advisable to connect the pipe feeding the filler direct with 

 the holding tank. The extent of elevation of the hokling tank 

 over the filler obviously controls the gravity pressure under 

 which the evaporated milk enters the filling machine. If the 

 holding- tank is located at a high elevation, therefore, the speed 

 of filling can be materially increased. 



SEALING. 



The filled cans should be capped and sealed at once. The 

 seal must be hermetical and strong enough to withstand the 

 strain of the subsequent sterilizing process. With the exception 

 of the "Sanitary can," seals without solder have so far proven 

 unsatisfactory in the canning of evaporated milk. They are 

 prone to weaken in the sterilizer and cause ''leakers." Most of 

 the cans on the market containing evaporated milk are, therefore, 

 sealed with solder. Sealing evaporated milk cans with solder 

 is by far the safest method. For details of methods of sealing 

 see Chapter VII. 



For the sealing or tipping of the venthole cans an automatic 

 tipper is usually attached to the filling machine, so that when 

 the cans leave the filling machine, they have also been sealed. 



It is exceedingly important that the sealing be done per- 

 fectly, because even minute leaks cause the evaporated milk in 

 the cans to become contaminated causing spoilage. In order to 

 detect cans with imperfect seals all the cans, as they come from 

 the filling and sealing machine, are carefully inspected for leaks. 

 This may be done by the use of a test bath consisting of a narrow 



