50 CREAMERY BUTTER MAKING 



these is blue. It is, however, not often met with in dairy- 

 practice since the color usually does not appear until the 

 milk is several days old. The specific organism that 

 causes blue milk has been known for more than half a 

 centurv and is called cyanogenous. Another color that 

 rarely turns up in dairy practice is produced by a germ 

 known as prodigiosis, causing milk to turn red. Other 

 colors are produced such as yellow, green, and black, but 

 these are of verv rare occurrence. 



