46 THE BOOK OF CHEESE 



ture. A very satisfactory arrangement is to cut off a 

 barrel, and place a steam pipe in it. The barrel can then 

 be filled partly full of water and heated by steam. The 

 bottles of milk to be pasteurized are hung in the water in 

 the barrel. Two or three more bottles should be prepared 

 than it is expected will be used as some of the bottles 

 are liable to be broken while cooling or heating. The 

 bottles should be filled about two-thirds full. This leaves 

 room enough to add the mother starter and later to break 

 up the starter to examine it. It is desirable not to have 

 the milk or starter touch the cover since contaminations 

 are more likely. It is a good plan when pasteurizing to 

 have one bottle as a check. This may be filled with 

 water and left open and the thermometer placed in it. 

 A uniform temperature may be obtained by shaking the 

 bottles. 



64. Adding cultures. After being pasteurized, the 

 milk should be cooled to a temperature of 80 F. This 

 is a suitable temperature for the. development of the 

 lactic acid-forming organisms. The commercial or pure 

 culture should now be added to the milk at the rate 

 specified in the directions. Care should be exercised in 

 opening bottles not to put the covers in an unclean place. 

 A sterile dipper is a good place to put them. After the 

 culture has been added to the milk, it should be mixed 

 thoroughly by shaking the bottle. This should be re- 

 peated every fifteen or twenty minutes for four or five 

 times. This is done to make certain that the culture 

 is thoroughly mixed with the milk. The milk should 

 be placed in a room or incubator as near 80 F. as pos- 

 sible, in order to have a uniform temperature for the 

 growth of the organisms. The bacteria in the pure 

 culture are more or less dormant so that a somewhat 



