126 MILK [vn 



to isolating the bacteria implicated are of the very 

 highest importance. The practical outcome of these 

 experiments has been the preparation of so-called 

 " pure cultures " for ripening cream. So far the use 

 of these pure cultures has been followed with the 

 very best results, and it has been found that the 

 quality of the butter improves as soon as these are 

 used. According to experts, the amount of the 

 improvement has been estimated at more than 20 

 per cent. At present it may be mentioned that 

 nearly every dairy in Denmark, Germany, Sweden, 

 and Holland, depends upon pure cultures of bacteria 

 to produce uniformly good qualities of butter, and it 

 is greatly to be desired that this practice should be 

 introduced into this country without loss of time. 

 Very favourable results have been found by using 

 such cultures for correcting certain defects in 

 butter, such as oiliness, fishy and litter flavours, 

 and a tendency to become rancid. One bacillus has 

 been isolated which seems to produce the proper 

 aroma in butter, when used in cultures for ripening 

 cream, and this ferment has been used in some of 

 the creameries of Germany with excellent results. 1 

 It may be interesting to note that the proper aroma 

 in butter seems to be connected with the first pro- 

 ducts of decomposition, set up in the cream as the 

 result of bacterial growth; for the bacteria which 



1 See Appendix to Chapter, p. 136. 



