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Conclusions that can be drawn from the examination of the specimens of milk as they
arrive from the farmer at the railway depots:—
(1) Bovine tubercle bacilli were found in two specimens out of 18, making a percentage of
11.
(2) Human tubercle bacilli were not found, showing that none had gained access to the
milk during the process of handling it.
(3) The only other pathogenic organism found was in one specimen where the B. paratyphosus
B. was found. This was typical in all its reactions.
Diphtheria and other important organisms were not found in any sample.
(4) Taking the amount of the spores of anaerobic organisms in the excreta of cows as
1-10 millions per gram, and remembering that these do not multiply in the milk
under ordinary conditions and so can be taken as a non-multiplying factor, it must
follow that the contamination of milk by the excreta of the cow is very slight as
seen in these samples. Even in the worst specimens where the reaction for these
organisms was given in quantities of 1 ccm. of the milk and not in 0.1 ccm., it follows
that the amount of contamination must be with about 1/100,000 to 1/1,000,000 of a
gramme of the excreta per ccm.
Taking this as a standard it follows that the number of B. Coli which originally got into
the milk in this way would have been 100-1000 per ccm. of the milk, taking the
dung to have 100 million B. Coli per gramme, but in many of the milks the
contamination must have been much less, because anaerobic spores could only be
demonstrated when much larger quantities of milk were examined.
Taking this as a guide it follows that the B. Coli. have multiplied greatly from the time of
the original contamination to the time when the milk arrived at the railway depot.
It thus follows that the milk was transported at too high a temperature, viz., a temperature
which allowed these organisms to multiply at a great rate.
(5) Finally, the great number of saprophytic organisms found in the milks show that
enough care has not been taken in the preliminary cleansing and scalding of the
containers.
Conclusions from the examination of the Pasteurised specimens examined.
There are three examples seen in Table II.
Specimen 8 was a sample of pasteurised milk resulting from the pasteurisation of a
mixture of farmers' milks sampled under the specimen numbers 2, 3, 4 and 5, and other
farmers' milks not sampled. It was taken immediately after pasteurisation. It is a fairly
good result. The contaminating organisms were practically all destroyed, and care was taken
with the utensils in the dairy.
Specimen 14 was a sample of pasteurised milk resulting from the pasteurisation of a
mixture of various farmers' milks. Specimens 11 and 12 were farmers' milks supplied to the
same dairy later in the same day. Here the process was not by any means as effectual as it
should be, and in addition the dairy utensils could not have been properly cleaned or the milk
was exposed in some way after sterilisation, whereby the milk became grossly contaminated
with saprophytic organisms.
Specimen 23 was a sample of pasteurised milk resulting from the pasteurisation of a
mixture of the two farmers' milks sampled under the specimen numbers 17 and 18, with no
other milks. Here the process was like the previous one, and there was the same defect
allowing gross contamination with saprophytic organisms.