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The Methylene Blue Test
The Minister of Health recommends the testing of ice cream by the
Methylene Blue Test. The basis of this test is that the amount of
bacterial contamination present is indicated by the time taken to
decolourise methylene blue dye. As pointed out, however, in the
Ministry of Health's Bulletin for March 1947, the conclusions and
suggested grading are at present provisional, but the Minister is advised
that this test of bacterial cleanliness appears to provide the best available
for the present purpose, at the same time it is simple and cheap to perform.
It is suggested that if out of the four grades recommended, ice cream
consistently fails to reach grades one and two, it would be reasonable to
regard this as indicating defects of manufacture or of handling which
call for further investigation.
Thirty samples of ice cream were taken during the year and sent to
the Central Public Health Laboratory, Hendon, for testing. The results
were as follows :—
Grade 1 Grade 2 Grade 3 Grade 4
5 2 11 12
Grade 1 showing, according to the test, the least contamination, and
grade 4 the highest.
When samples have consistently fallen into Grade 4, observations
have been kept on the methods of manufacturing and handling with a
view to the product'on of a cleaner ice cream.
RODENT CONTROL
During the twelve months ending 31st December, 1948, the following
work was carried out under the Rats and Mice (Destruction) Act 1919 :—
Visits by the Sanitary Inspectors 145
Visits by the Rodent Operator 3,431
Premises disinfested for Rats 191
Premises disinfested for Mice 57
No evidence of infestation —
Disinfestation in hand—Rats 138
Disinfestation in hand—Mice 92
The investigation of complaints of rat and mice infestations at
private and business premises is carried out by the Sanitary Inspectors.
The disinfestation of the premises either by gassing, poisoning or trapping
is performed by the Rodent Operator.
Regular sewer maintenance treatments were carried out during the
year.
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