View report page

37
Further information with regard to the milk containing tubercle bacilli
follows: —
Sample "N."—Slight infection only, a few tubercles were noted on the liver
of the guinea pig inoculated. This sample was purchased from a retail dealer
occupying a general shop; he obtained the milk from a large wholesale Company;
communications were addressed to this Company in order to ascertain the source
of supply. After some correspondence a letter was received from the Managing
Director stating that as his Company handles thousands of gallons of milk daily
it was not easy to trace the source of supply. He suggested, however, that the
Company's carman might have taken a churn of milk direct from the station to
the premises of the retailer without the milk going through the Company's
pasteurising plant, contrary to their rules. This communication can only be
regarded as unsatisfactory indicating, as it does, the reliance on pasteurisation to
secure the delivery of milk free from infection, rather than on the production and
delivery of clean milk free from tubercle bacilli. Moreover, it confirms the
experience gained in previous years that owing to the practice of distributing milk
from large mixing depots it is frequently inipracticable to trace the actual source of
an infected milk supply.
Sample "S" was purchased from a fairly large milk shop. On enquiry it
was ascertained that the milk was supplied to the retailer in this Borough by a
Derbyshire Company. A communication was addressed to the Company who
replied that milk is collected by them from about 150 farms and taken to their
depot where it is mixed in a receiving vessel and " heat treated "in a flash
pasteuriser to a temperature of 167° F. and immediately cooled over a brine cooler
down to about 30° F. This Company also pointed out that it was practically
impossible for them to detect the farm from which the infected milk came; in
this case also it would appear that pasteurisation is relied on rather than the
production of clean and non-infected milk. The Holborn Council, however, in
this instance had the satisfaction that their efforts to obtain purer milk were not
blocked by a mere non possumus. Information respecting this sample was sent to
the County Medical Officer of Derby who replied that he had arranged with the
Company that their farmers should be notified of the presence of tubercle bacilli
in the mixed milk from the 150 farms and that they should be instructed to keep
particular watch on their beasts. In addition to this the Company instructed their
Factory Managers to look into the farms under their control and endeavour to
trace the source of infection sufficiently nearly for the County Medical Officer to
take action under the Tuberculosis Order.
Sample "V."—This sample was purchased from a milk seller occupying a
small general shop. The milk was obtained by the retailer from a dairyman in the
Borough. Information was obtained from the wholesale dairyman that the milk
from which this retailer was supplied was obtained from Derbyshire and that about
the time that the sample was taken, the milk came from a farmer, who since that
date had had all his cattle destroyed owing to foot and mouth disease.