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the sources of origin and the consequent difficulties of tracing to their source incriminated
milks, are obvious. One of these containers may hold 3,000 gallons of
milk which may have come from over 200 farms, and at any one of these farms the
herds may be of considerable size.
The transport of mixed milk in bulk, in addition to aggravating the difficulty
of tracing tubercle-infected milk to its origin, has another two-fold effect:—(a) The
introduction of a single infected milk into the tank infects the whole of the milk in
the tank; (b) the dilution of a tubercle-infected milk by a large volume of milk
not so infected must necessarily reduce the dose of tubercle bacilli which any one
consumer receives. Whether on balance this is an advantage or not cannot at present
be decided. Intensified dosage is certainly more dangerous, but the wider risk of a
more diluted infection may not be without its dangers. It is considered that the
increase in the percentage of samples of milk found to be tubercle infected may be
explained by the wider diffusion of tubercle bacilli in the bulked milk. The attention
of the Ministry of Health has been drawn to the matter, and it is hoped that a system
will be devised which will reduce the difficulties now being experienced in the efficient
administration of the Milk and Dairies (Consolidation) Act, 1915.
During the year it was reported in the case of 397 samples, that the infected
guinea-pigs had succumbed to an acute intercurrent infection by some organisms
other than tubercle contained in the milk. It was stated in the report for the year
1927 that the death of the guinea-pig was caused by lethal organisms usually present
in the milk. The presence of these organisms was due to dirty conditions of the
cow's udder, to dirty cowsheds and generally to faulty practices in the production,
storage and transport of milk. For this reason the practice was begun of notifying
the county medical officers of health concerned of these cases in order that they
might take such action as appeared desirable. During the past year many striking
reports have been received from the county authorities as to the conditions found at
farms inspected as a result of these notifications. A correlation appears to exist
between the death of the guinea-pig and unhygienic conditions at the farm. In
some instances, however, the conditions found at the farm were free from objection
and nothing could be detected that would account for the condition of the milk.
It does not follow necessarily that a guinea-pig dying of an acute intercurrent infection
following the subcutaneous injection of milk has been infected by the milk,
but such an occurrence suggests the desirability of inspecting the conditions of milk
production at the source. So far as is practicable, an indication of the milk origin
or otherwise of the infection is obtained, and particulars based on this further information
are now transmitted to the county authorities concerned.
While engaged in milk sampling, the Council's inspectors sometimes observe
conditions, either of the milk or of the churn, which contravene the provisions of
the Milk and Dairies Order, 1926. This applies more especially (1) to the temperature
of the milk, the regulations concerning which are laid down in Article 24 of the Order,
and (2) to the cleanliness and condition of the churns, which are dealt with in
sections 27, 28 and 29 (2) of the Order. The Council is not the authority responsible
for the enforcement of these sections of the Order, and details relating to contraventions
of these articles of the Order are transmitted to the authorities concerned.
The consignments in respect of which contraventions of the requirements of the
Milk and Dairies Order were observed in all amounted to 130 churns.
In compliance with the instruction of the Mental Hospitals Committee, samples
of milk have been taken twice a year from the supplies of the herds at each of the
institutions under the direction of the Mental Hospitals Committee. In all 78
samples were taken. Of these three were found to be tubercle infected, in 16 cases
the guinea-pig succumbed to an acute intercurrent infection, and in the remaining
59 cases tubercle was not detected. The percentage of samples found to be tubercle
infected of the total number of completed examinations made was, therefore, 4.8.