London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
Stepney 1931
[Report of the Medical Officer of Health for Stepney]
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A further confirmation of the fact that the samples did not consist of natural milk was obtained by determining their respective freezing points.
| Fat per cent. | Solids-not-fat per cent. | Freezing Point. | ||
|---|---|---|---|---|
| 3.3 | 9.45 | -0.600° C. | ||
| D 31 | 3.2 | 9.60 | -0.606° C. | |
| Reconstituted milk made in the laboratory from dried milk | 1 | — | 8.37 | -0.510° C. |
| 2 | — | 8.83 | -0.550° C. | |
| 3 | — | 9.54 | -0.605° C. | |
| Natural milk (average) | 3.6 | 8.80 | —0.535° C. to —0.560° C. | |
The percentage of fat does not affect the freezing point. It will be
seen from the above that in the case of reconstituted milk the depression of
the freezing point increases with the content of solids-not-fat; in natural
milk, whatever its composition the freezing point is little affected.
Legal proceedings were taken and in each case the summons was dismissed
without costs.
It will be seen that where the solids-not-fat is normal for milk as in the
laboratory sample No. 2, the freezing point is also normal, so that the determination
of the freezing point would not be of use where the reconstituted
milk had been so made that the product contained fat and solids-not-fat
in the proportions found in normal milk.
In a similar case at Battersea the defendant admitted that the milk
was reconstituted from dried separated milk mixed with cream and water
and homogenised. The summons was dismissed under the Probation of
Offenders Act the vendor paying £2 2s. 0d. costs.
40 samples were examined. Of these 4 failed to comply with the
requirements of the Regulations. In 2 cases offences were committed with
regard to labelling.
Certified Milk and Grade A Milk (Pasteurised).—The milk must not
contain more than 30,000 organisms per c.c. and must not contain coliform
bacillus in 1/10 c.c.
2 samples of Certified Milk showed 300 and 4,430 organisms per c.c,
respectively and the coliform bacillus was absent in 1/10 c.c,
Bacteriological
Examination
of Milk.