TAINTS AND DEFECTS OF BUTTER 349 



flavour must be attributed, and not to any one substance 

 only. 



Much research has been carried on to determine the 

 kind of organisms which produce perfect flavour and 

 aroma. No single species of bacterium, however, has 

 been found to be able to give the desired result when 

 used as a pure culture and inoculated into sterilized, 

 pasteurized, or ordinary cream. Some of them isolated 

 by Conn, S torch, Weigmann, and others, have given a 

 good butter when used singly in this way, but not one 

 with all the good qualities of a first-class sample. 



It is pretty well established that the organisms which 

 influence or induce flavour and aroma do not belong to 

 the class which are specially concerned with the lactic 

 acid fermentations, but rather to those which induce 

 alkaline and putrefactive changes. 



On this assumption it is likely that they would ruin 

 the butter if allowed to get the upper hand or a free 

 field for development ; they are, however, ordinarily kept 

 in check by the lactic acid bacteria. 



4. Taints and Defects of Butter. Many of the faults 

 which reduce the flavour and market-value of butter are 

 due to want of skill in churning and general dairy 

 management, as well as to the nature of the food con- 

 sumed by the cows. 



The fats of milk may be of low melting-point, and 

 the butter consequently soft and oily, owing to the use 

 of linseed-cake as food, or the butter may be too hard 

 from the consumption of too much cotton-cake by the 

 cows. Streakiness, or mottling, may be caused by 

 irregular salting or the presence of specks of casein 

 owing to over- ripening of the cream. Offensive flavours 

 may arise from giving the cows turnips or cabbages, or 



