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29
BACTERIOLOGICAL AND CHEMICAL EXAMINATIONS OF MILK.
Samples Collected at Railway Stations.
As has been customary for some years past, a series of samples of milk arriving in the
City of London from the country was collected in September and October at Liverpool Street
Station, and submitted to Sir Frederick Andrewes, K.B.E., the City Bacteriologist, for bacteriological
examination and investigation as to the presence of dirt.
A duplicate of each sample was also submitted to Mr. E. A. Pinchin, B.Sc., the Public
Analyst for the City of Lodnon, for chemical examination.
The samples were collected with particular regard to cleanliness.
In all, 48 samples were collected, and these were sent from different farms situated in
the following Counties:—
Cambridge 7
Suffolk 18
Essex 8
Norfolk 11
Shropshire 2
N. Wales 1
Leicester 1
48
The following is a summary of Sir Frederick Andrewes' report on the result of the bacteriological
examinations:—
"As regards Dirt.—The milks as a whole more remarkably clean as compared with what
used to be the case 10 years ago. Of the 48 samples, I have noted 31 as clean and 17 as
containing a trace of dirt—i.e., a few blackish specks in the sediment. No specimen deserved
to be called dirty."
"As regards Tubercle.—The results have been quite unequivocal. 44 specimens were
undoubtedly free from tubercle bacilli; 4 specimens certainly contained them—i.e., 8.3%,
or 1 in 12, of the milks delivered at railway stations in the City of London were tuberculous."
These results, considering the few examinations, are not of great statistical import, but
suggest that past records, such as those of the year 1926, turned on the toss of a coin.
The details in connection with the four cases in which the Tubercle bacillus was present
were forwarded to the appropriate Medical Officers of Health. The following are extracts
from reports which have been received, indicating the conditions on the farms of origin:—
Sample No. 11.—"We examined 64 cows, none of which showed definite signs of tuberculosis,
and seven specimens were taken and examined microscopically and found to be
negative. One cow was in an unhealthy condition and milk had apparently been taken from it
at the time of your complaint, but the cow will not be used to supply milk in future."
"Subsequent animal inoculations indicated the presence of tubercle in the milk from
this farm, and I am informed that the matter has been referred to the Diseases of Animals
Act Committee."
Sample No. 12.—"The Veterinary Inspector found that one red shorthorn cow named
'Buff' had induration of the udder and enlarged supramammary glands, and he was of
the opinion that this cow was suffering from Tuberculosis.
"The milk from this cow was examined microscopically and acid-fast bacilli were found.
The cow was then immediately slaughtered under the Tuberculosis Order, 1925, and the
post mortem examination revealed that the animal was affected with Tuberculosis of the
lungs, udder and supramammary, bronchial and mesenteric lymphatic glands.
"In addition, the Veterinary Inspector found a red shorthorn cow named 'Brandy'
with induration of the udder and enlarged supramammary glands, a black and white shorthorn
cow 'Mabel' with enlarged lymphatic gland of the right forequarter, a brindled shorthorn
cow ' Paggy' with enlarged supramammary lymphatic gland, and a black and white
shorthorn cow ' Susan' with induration of the udder.
"A separate sample of milk was taken from all these cows and examined microscopically
with negative results. Guinea-pigs have been inoculated with each of these milks and I will
communicate with you later when the results are known.
"The milks of the 42 cows which constituted the rest of the herd were mixed, and a
sample taken and examined microscopically with a negative result. An animal inoculation
test is also being made with this sample of mixed milk, and I will let you have the final
result when the investigation has been completed."
The following is an extract from a subsequent letter:—
"The mixed milk of the other 42 cows, which was considered to be sound, has proved to
contain tubercle."
The circumstances are being investigated at the farm. *
e