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84
examined bacteriologically with the results shown in
the Table on page 85. All the samples except six,
however, contained less than 100,000 bacteria per c.c.
and the great majority were well within the standard
for pasteurised milk. These tests are of assistance as
an object lesson to the dairymen and their employees,
showing the necessity for hygienic methods, especially
in bottling.
Sterilised Milk. This is milk which has been
heated to a much greater extent than pasteurised
milk. All the germs are killed, not only those which
are capable of producing disease, but also those which
cause decomposition of the milk on being kept.
Sterilised milk therefore, keeps much longer than
either ordinary or pasteurised milk, and for that
reason it is used when daily supplies are unobtainable,
as on board ship. It is also useful for export, especially
to warm countries. Sterilised milk has, however, been
subjected to so much heat that most of the vitamins
are destroyed and the heat also causes some of the
valuable lime salts to be deposited and partially lost.
Pasteurised milk is much to be preferred, besides
being cheaper. Sterilised milk should not be used as
a routine food for infants.
Six samples were taken during the year for
bacteriological examination with the results shown in
the table. It will be seen that according to the tests
only one sample was absolutely sterile, four gave counts
of less than 100 bacteria per cubic centimetre, and one
showed 380 bacteria per cubic centimetre. As one
would expect, the bacillus coli tests were negative in
all six cases.
Milk and Cream.
Articles.
Number of samples
examined for the
presence of a preservative.
Number of samples
in which a preservative
was found to
be present.
Milk and separated
milk
543
-
Cream (including
tinned cream)
8
-