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milk when heated loses some of the enzyme it normally contains and which
acts as a reducing agent.
The originators of the test claim that it can show—
(a) whether milk has been heated to 1½ degrees F. below the
minimum temperature for pasteurisation, or
(b) whether it has been heated (at 145 degrees F.) for 20 minutes or
less, instead of the required 30 minutes, or
(c) whether raw milk (down to 0.25 per cent.) has been mixed with
properly pasteurised milk.
If, on the other hand, milk has been heated over 145 degrees F. or for a longer
period, this is not necessarily shown in the result of the test except that the
test remains negative as with properly pasteurised milk. This, however, is of
no importance from the health point of view as the greater the heating or the
longer the period for which the milk is heated the safer the milk becomes
bacteriologically. During the year 24 samples were tested in this way at the
National Institute for Research in Dairying. The 24 samples consisted of 21
samples of officially pasteurised milk and 3 samples of milk which were not
being sold as officially pasteurised. All were negative except the three which
were not pasteurised.
Milk Vessels.
Considerable attention continues to be given to improving the methods
of cleansing and sterilising milk bottles and utensils. Under Article 21 of the
Milk and Dairies Order the use of steam or boiling water for scalding all milk vessels
is required. The cleansing of bottles in which milk is delivered is a matter
which often receives insufficient attention. Milk bottles are included under
Article 21 of the Order and therefore should be cleansed by means of steam or
boiling water in the same way. Exposure of milk bottles and utensils to steam
is necessary for the protection of the public. It is also an advantage commercially
as when the bottles and milk receptacles are sterilised the milk keeps better
and the dairyman gains thereby.
A problem to which attention has been called before but, because of its
importance, is again repeated here is one which affects both the milk retailers
and the general public, and is that of the disposition of empty milk bottles.
These, if they are not handed to the milk purveyor at his next call, should be
placed in a position where they cannot easily be contaminated. The door-step
is not ideal for this purpose, but is very much better than the method commonly
adopted of leaving the bottle on the pavement. This latter method gives rise
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