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The Public Analyst was able to advise the chemist on the steps to be
taken to precipitate and remove the sodium fluoride. The wine was put under
stop by the Food Inspector, samples were analysed and 100 to 250 parts of
sodium fluoride per million were found.
Samples were then analysed after treatment of the wine for the removal
of the sodium fluoride, and were found to be satisfactory. The wine was then
released for sale.
Tin in Sugar.—In May, a letter was received from the Medical Officer of
Health, Hampstead, stating that a sample of Barbadoes Soft Raw Sugar
showed, on analysis, the presence of 2.1 grains of tin per pound, and 140 parts
of sulphur dioxide preservative per million parts of the sample. (The Public
Health (Preservatives in Food) Regulations limit the amount of S02 preservative
in sugar to 70 parts per million.) The sugar camplained of came
from a warehouse in the Borough.
9 samples of sugar were taken from the warehouse for analysis. 1 sample
contained 104 parts of S02 per million, and 1 contained 1.87 grains of tin
per pound.
After considerable correspondence and action on the part of the Food
Inspector, all the affected sugars were recalled and refined of tin and preservative
before being released for sale. A letter was also received from
Dr. Seymour, of the Ministry of Health, requesting that he be given information
relating to the analyses of sugar samples and the action taken by this
Department. The use of tin as a mordant for the colouring matter in the
preparation of brown sugar is not very generally known. The Annual Report
of the Chief Medical Officer of the Ministry of Health for the year 1929 states:-
"Recent enquiries show that practically all the sugar sold in this country
as Demerara or West Indian crystallized, contains tin. The amount is not
large, ranging from 0.33 to 1.33 grains per pound. At the same time it is
questionable whether a manufacturer is justified in adding tin salts to a food
supply solely for the purpose of colouring it. Such an addition would appear
to be quite unnecessary. It cannot be said categorically that a grain of tin
per pound of sugar is prejudicial to health, but on general principles, the
amount of tin, and of heavy metals generally, in food should be kept down
to the lowest possible limits."
As a result of the action taken in this matter, all existing parcels of sugar
coming forward are now being analysed for the presence of tin and sulphur
dioxide in excess, and where these are found, the parcels of sugar are being
refined before sale.
The trade has also discontinued the sale of bright-coloured soft sugars
as these were found most liable to contain tin in excess, and grey sugars are
being substituted. In addition to the usual guarantee being given to dealers,
"First-hand" importers are further guaranteeing that the sugar has been
analysed for tin and S02 in excess.
860 five-kilo tins of black currant pulp, landed at a wharf in the Borough
from France, were detained for the reason that a considerable proportion
showed indication of having been re-soldered. On a full examination being
made, 511 tins were sound and satisfactory, 253 tins resoldered and unsatisfactory,
and 96 tins unsound. A request was made for the release of the
253 resoldered tins for re-export to Paris. This was refused and the resoldered
tins were surrendered and destroyed, together with the unsound tins.