CHAPTER XIII 
BACTERIA IN BUTTER AND OLEOMARGARINE 
BACTERIA IN BUTTER-MAKING 
In the making of butter, bacteria are the dairyman’s allies. 
The butter-maker always, even though unconsciously, makes 
direct use of bacteria when he subjects his cream to a process al- 
most universally adopted in butter-making, called ripening, or, in 
Europe, more commonly called souring. In butter-making, the 
cream is not usually churned immediately after it is separated from 
the milk, but it is allowed to lie in a moderately warm vat for a 
period of twelve to twenty-four hours or even longer, that it may 
ripen. In some places there is a demand for what is known as 
sweet cream butter, which is simply butter made from fresh cream 
without ripening; but such a demand is very limited, and most 
butter is made from ripened cream. 
CREAM-RIPENING 
The custom of ripening cream is an old one, doubtless as old 
as the process of butter-making. Upon a farm where the amount 
of cream is small, it is always necessary to allow it to accumulate 
for some days till there is sufficient for a proper churning. During 
this period it is sure to undergo ripening without any intention on 
the part of the farmer. On ordinary farms, the cream is left to 
take care of itself, and is thus sure to be ripened by the time there 
is enough to churn. But the centralization of butter-making into 
creamerles, where large quantities of cream are handled daily, has 
put a new aspect upon the problem. The ripening will no longer 
care for itself, but must be carefully attended to by the butter- 
maker. The necessity for some accurate means of controlling the 
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