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34
Biological Examination of Milk for the presence of
Tuberculosis. Seven samples of milk were submitted during
1946 for what is commonly called the 'animal test', since
the use of guinea pigs is involved. In no instance was
the presence of tubercle bacilli detected.
Pasteurised Milk. The test which is usually applied to
milk to ascertain whether it has been satisfactorily
pasteurised, is known as the Phosphatase test. It has
been used as an unofficial standard for several years,
but during 1946 it was officially recognised by the
Ministry of Health. This action was generally welcomed
by Health Officers, but the decision of the Minister to
replace the plate-count by a half-hour methylene blue test
was viewed with less favour.
The object of the latter test is to ascertain the
condition of the milk so far as cleanliness, and keeping
quality, are concerned. Whilst it must be admitted that
the plate-count was subject to wide variation in results,
it was popular as a general guide to the degree of cleanliness,
and it was a test which impressed the farmers. However,
experience over a period of time will be required
before a proper assessment may be made of the value of
the change of test.
During 1946 a new short term high temperature
pasteurising plant was installed in a dairy in the borough.
It was intended to be used for the heat treatment of T.T.
milk to be bottled on the premises.
Bacteriological Examination of Ice-Cream.
The year 1946 marked a great increase in the interest
shown by the public in the quality of ice-cream, but this
interest, although encouraging to food officers, is still
far below the degree of discrimination which one would wish
to observe. It is an axiom that advances in legislation
generally follow public demand. In the same way, if the
efforts made by food officers to prevent the sale of unclean
ice-cream were to receive the full support of the public,
the presence of gaudily painted barrows and open ice-cream
containers at street corners would automatically cease.
whilst the public continues to purchase unsatisfactory icecream
from these itinerant vendors, so long will responsible
government departments accept the fact as an indication that
all is well, and nothing further need be done. Food officers
know only too well the weakness and dangers of the existing
methods, but beyond constant but limited supervision of the
place of manufacture, they are helpless by reason of the
absence of any recognised and enforceable standards of
cleanliness and quality. So far as cleanliness is concerned
the Corporation has adopted as a guide a maximum bacterial
count of 100,000 per cubic centimeter and absence of B.Coli
in a dilution of 1/100th. This cannot be regarded as unreasonably
high, yet no less than 20 samples failed to reach
it out of 50 samples subjected to the tests during 1946. In
those cases where the samples were of ice-cream made in the
borough, every effort was made to trace the cause of the
low standard. Inspections were made during the process of
manufacture, and the cleansing of the equipment and utensils
was carefully supervised. The most frequent cause for failure
was found to be inadequate cleansing of utensils.