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118
Percentage of Solids-not-Fat.
Quarter. 1934 1935 1936 1937 1938
January-March 8.80 8.85 8.76 8.70 8.72
April-June 8.86 8.85 8.78 8.68 8.73
July-September 8.69 8.67 8.70 8.61 8.63
October - December 8.97 8.86 8.81 8.79 8.76
Whole Year 8.83 8.81 8.77 8.71 8.72
The results are typical of the milk supply in the Metropolitan area and show that
a satisfactory standard, considerably above the minimum of the Sale of Milk
Regulations, 1901, has been maintained in Woolwich.
It will be noticed that the similarity in composition of the milk obtained in
corresponding seasons is remarkable. In solids-not-fat, the greatest variation in
the five years is 1 per cent; in fat content the variations are greater, and it is
probable that weather conditions may have had some effect on these figures.
A prolonged dry period adversely affects the available pasture and the low
fats of October-December, 1934, July-September, 1937, and April-June, 1938, were
found in Quarters where the rainfall was considerably below normal. Similarly,
the meteorological records show high rainfalls in April-June, 1935, and OctoberDecember,
1935.
It will also be noticed that the fat content regularly rises with the onset of
cold, the early winter figures being the highest; probably by design of nature to
supply the greater needs of the calf. The very cold months of May in 1935 and
January and February in 1936 may thus have influenced the high fats in the Quarterly
averages.
The freezing point test for added water in milk, the applications of which were
explained in the analytical notes in the 1935 Report, was again proved to be of
value.
A number of samples submitted in the early part of the year showed borderline
figures for solids-not-fat, and the milks would have been passed as " possibly
genuine " before the adoption of this test; they were found, however, to have
freezing points which definitely indicated small amount of added water and they
were accordingly reported against. In every instance, the sample was traced back
to the same source of supply, a large dairy delivering milk in Woolwich; but on
communicating the results of the analyses, the presence of any added water was
strenuously denied by the management. The company nevertheless agreed to
have check analyses made at various stages in the dairy by an independent firm of
analytical chemists, and in some instances quantities of added water up to 15 per
cent. were discovered in these samples; it eventually appeared that water was
being intr0duced into the milk at certain times when the supply pipes were rinsed
out, through careless handling of the cocks.