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specified areas were required instead to sell or supply pasteurised milk,
sterilised milk, or tuberculin tested milk.
Producers licences under these Regulations are granted by the Minister of
Agriculture and Fisheries and Dealers' Licences by the Local Authority.
The following licences were issued by the Borough Council:-
Dealer's Licence - Tuberculin Tested Milk 43
Dealer's Supplementary Licence - Tuberculin Tested Milk 19
During the year 17 samples of raw milk were submitted for biological
examination for tubercle bacilli and 14 were negative; two samples were void
as the guinea pig died before completion of the tests. One sample showed a
POSITIVE result. The milk in question was bottled by a producer in the County
of Middlesex. Distribution of this milk was immediately stopped and a
veterinary investigation of the herd carried out. Some two months later,
following a Clearance Certificate from the Divisional Veterinary Officer of the
Ministry of Agriculture and Fisheries, distribution of the supply was resumed.
(c) milk (special designation) (pasteurised and sterilised milk) regulations,
1949 to 1953. Milk sold under the special designation "pasteurised" must be
treated by one of the three following methods:-
(a) heated to a temperature of not less than 145°F. and not more than
150°F., held at that temperature for at least 30 minutes and be
immediately cooled to a temperature of not more than 50°F., or
(b) heated to a temperature of not less than 161°F., held at that temperature
for at least 15 seconds and be immediately cooled to a
temperature of not more than 50°F., or
(c) heated to such temperature and retained thereat for such period as
may be specified by the licensing authority with the approval of the
Minister of Food.
"Pasteurised" milk is required to comply with two tests: The Phosphatase
Test is an indication of adequate heat treatment and is based on the fact that
the enzyme phosphatase is destroyed by efficient legal pasteurisation, but is
not completely destroyed if the milk is heated only to lower temperatures or
for shorter periods than those prescribed. The test is a colorimetric one and
deemed to be satisfied by milk which gives a reading of 2.3 Lovibond blue units
or less. The Methylene Blue Test provides an index of bacterial cleanliness
and shall be deemed to be satisfied by milk which fails to decolourise methylene
blue in 30 minutes. The following samples were submitted to the Public
Health Laboratory Service for tests under these regulations:-
Pasteurised milk Phosphatase Test 455
Methylene Blue Test 455
Tuberculin Tested (Pasteurised) Milk Phosphatase Test 94
Methylene Blue Test e. 94
Ten samples of milk (Pasteurised) failed to comply with the requirements
of the Methylene Blue Test, but in each case the test was void owing to the
atmospheric shade temperature on the day of sampling exceeding 65°F. One
sample failed to satisfy the Phosphatase Test, The milk in question was
pasteurised and bottled in a neighbouring borough; on investigation it was
ascertained that the cause of the trouble was due to a temporary defect in the
plant. One sample of Tuberculin Tested (Pasteurised) milk was submitted to
the biological test for tubercle bacilli and was negative,
"Sterilised" milk is milk which has been filtered or clarified and homogenised
and heated to and retained at a temperature of not less than 212°F. for
such period as to ensure that it will comply with the prescribed turbidity
test: the fifty-one samples submitted for examination satisfied this test.
Licences authorising the use of special designations in the case of pasteurising
and sterilising establishments are issued by Food and Drugs Authorities,
and in the case of dealers' principal and supplementary licences by local
authorities.
The following licences were issued by the borough council:-