REGULATION OF PEODUCTION 181 



may not exceed 10° C. (50° F.). Milk should be kept 

 chilled until it is ready to be shipped and then it must be 

 guarded carefully against high temperature by protect- 

 ing it from the sun, transportation by night, etc. 



If the transportation of milk requires a long time, it 

 must be cooled to a low point, and, while it is not well to 

 allow the whole quantity to freeze, in recent years a 

 partly frozen milk (the outside layer frozen m the cans) 

 or the addition of frozen milk to the other milk have 

 been successfully used. 



[Milk shipped long distances in America is sent in 

 refrigerator cars. Some milk is on the railroad 10 hours 

 before it reaches market. Milk shipped short distances 

 is usually not sent in refrigerator cars because, on the 

 short runs, the cars have to be opened so often at local 

 stations that there would be a great consumption of ice. 

 If such milk is thoroughly chilled by the use of ice before 

 it is shipped, it usually arrives in good condition; but 

 if it is cooled only by the use of well or spring water it 

 is an uncertain commodity in the hottest weather. Bot- 

 tled milk is shipped in wooden boxes with broken ice 

 packed around the bottles. 



Helm *" has proposed that milk shall be shipped in 

 square, instead of round, cans, so that they may be 

 packed more closely and thus make a solid block, of 

 low temperature, which may be covered over if neces- 

 sary, and which will remain cold much longer than a 

 loose collection of round cans, between which the 

 warm air may freely circulate. This style of can is 

 shown in figure 14. L. P.] 



Only well-tinned metal cans which are easily cleaned 

 should be used for keeping milk (Fig. 13) ; these should 

 be closed and sealed when transported by rail or boat. 



*5 Wilhelm Helm, Die Milchbehandlung, liepzig, 1903. 



