ners used or from other
sources. To insure these conditions the jars must be thoroughly
cleaned and then sterilized just before use by placing them in cold
water and bringing them to the boiling point, or sterilized by a
thorough steaming. The sample of milk of a patron must be taken so
as to avoid contamination from the milk of the other patrons. This
can best be done by filling the jars as the milk is poured from the
patron's can into the weigh can. In cutting the curds, the knife
used must be dipped in hot water between each test to cleanse the
same. In short, the test should be carried out with great care so
that the tester is certain of the results obtained.

Other tests for the bacteriological condition of milk will be
described in Chapter IX.

=Overcoming abnormal fermentations.= The lactic acid bacteria are
often looked upon as normal to milk, and it is certain that they are
to be classed as harmful, only as they injure the keeping qualities
of milk. In milk designed for butter and cheese their presence is
necessary. At times these desirable forms of bacteria may disappear,
and be replaced by less desirable types. In one case it was observed
that the usual lactic bacteria had been replaced in a cheese factory
supply by an acid-forming organism that produced an intensely bitter
taste in the milk, thus rendering the cheese of no value. When such
harmful forms appear, they must be overcome, and the normal types of
bacteria replaced. A thorough cleaning of the milk utensils,
attention to the cattle and all places from which such bacteria may
find their way into the milk is often sufficient to cause a
disappearance of the trouble. If the acid-forming bacteria have
disappeared, the inoculation of the milk with cultures in ways later
to be discussed is often of advantage. At times more stringent
measures must be employed in order to destroy the harmful bacteria,
such as the use of strong disinfectants.

=Disinfection and disinfectants.= If any building or room becomes
infected with disease-producing bacteria, or if organisms causing
abnormal fermentations become established in a factory, the use of a
disinfectant that will destroy with great rapidity the life of
bacteria is necessary. The disinfection of all types of dairy
apparatus and utensils can be accomplished by thorough cleansing,
and by the use of steam or boiling water. The disinfection of rooms
and stables cannot be so readily accomplished.

Considerati