, while if it comes from
a deep well that is properly protected from surface contamination,
the bacterial content of the water will be low and no injurious
effect on the butter will be noted. When it is impossible to obtain
pure water for washing purposes, a proper supply may be secured by
sterilizing the water. The most convenient way of heating the water
is by the direct injection of steam. It is necessary to use that
coming directly from the boilers and not the exhaust from the
engine, since the latter is likely to contain small amounts of oil
that will impart to the butter an objectionable flavor. After
cooling, the water is ready for use. It has been shown that the
cost of treating an impure water is more than covered by the
increased returns from the product.

A pure and healthful water supply should be one of the essential
things of every dairy, creamery, and cheese factory, not only for
the sake of the quality of the product, but also to avoid
contamination of products with disease-producing bacteria.

=Bacteria in butter.= The germ content of butter will depend on the
type of cream. Sweet-cream butter contains but few bacteria. In
sour-cream butter the content in bacteria will be greatly increased,
especially as to lactic organisms. Often, it may amount to several
millions of organisms per gram. The germ content of butter is said
to be greater on the outside of a package than within the mass, due
doubtless to the free access of air, thus favoring the growth of the
aerobic forms.

The composition of normal butter does not favor the growth of the
majority of kinds of bacteria that are contained in it. The washing
process removes much of the material suitable as food for the
bacteria, such as sugar and albumen. If considerable butter milk is
left in the butter, the growth of bacteria will be quite rapid, at
first, but does not continue for any considerable length of time.
The addition of salt also tends to restrain the growth of most kinds
of bacteria.

Butter is at its best when it is perfectly fresh. Deterioration
begins within a short time and the rapidity with which the changes
go on is dependent on the temperature at which the butter is stored.
The temperature of the butter rooms in the large cold storage plants
is kept below 0 deg. F. The butter in such rooms will deteriorate very
slowly, but on removal from the cold rooms and in storage at
ordinary temperatures deterioration goes on more rapidly than