540 



STATE BOARD OF AGRICULTURE. 



step ill the iiiauiifacturiiig maiiipiilatioiis (Fig. 3). During pasteuriza- 

 tioii about 70 percent of this group is killed. In the pasteurized cream 

 they constituted over 50 percent of tliis total flora and about 95 per- 

 cent in the ripened cream. During the twenty to thirty minutes of 

 churning about 30 percent of the total flora were rendered unable to 

 make a growth on the culture media ; according to our data the starter 

 group suiTered the total of this loss. In butter they die more rapidly 

 than the members of the other groups. 



The gas producing hactcria and liqucfiers. These groups which cause 

 most of the undesirable flavors sufter great loss during the pasteuriza- 

 tion. They increased during the ripening and their numbers were not 

 reduced by churning. In butter their numbers remained almost con- 



F i g. 3. Graphic representation of the different types of micro- 

 orianisms in per cent of the total flora found at different steps in the 

 manufacture of butter (average of twelue churnings). 



stant. The gas producers including both the coli-aerogenes and the 

 enteritidis sporogenes groups were present in varying numbers in the 

 cream at all stages, but Avere not found in the butter. Other Avork in this 

 laboratory shows that members of the coli-aerogenes group are found 

 occasionall}^ in butter after three weeks in storage. For their absence 

 in butter we have no explanation to offer unless the agitation during the 

 churning or the plasmolysis of the cell due to the added salt is destruc- 

 tive. 



The inert or indiffcrcjit group of bacteria to which 10 to 25 percent of 

 the total flora belong suffered a loss of about 97.5 per cent during pas- 

 teurization ; increased during ripening, did not decrease during the 

 churning and remained almost constant in the butter during thirty 

 days. 



Torulae and molds. Torulae, both liquefying and non-liquefying were 

 found in every churning, pasteurization is highly destructive yet they 



