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Out of these SOS samples, 476 may be regarded as quite satisfactory,
and it is, perhaps, inevitable that attention should be given to
the 29 adulterated or unsatisfactory samples rather than to comment
on the virtues of the others. No new forms of adulteration have been
noted during the year, but there is, as often happens, a recrudescence
of well known sophistications. The subject of metallic contamination
of food continues to call for attention and one may venture to hope
that the new legislation which the Minister of Health hopes to
introduce during the present year may clarify the law and practice in
relation to this rather difficult subject.
A number of samples of Sugars of the Demerara type have been
found to contain relatively substantial quantities of tin. This is not
a new phenomenon; indeed it has been known for about fifty years
that a small quantity of tin was used in the manufacture of these
types of sugar. Its function is apparently to act as a mordant for the
natural colouring matter of the sugar. Rut although sugar has for
many years contained traces of tin, the amounts which have been
found recently seem to be substantially higher, though only in a few
cases did they exceed 2 grains per pound. There is a commonly
accepted limit of 2 grains per lb. for tin in canned foods, but this
refers primarily to unavoidable contamination due to storage in tinplate,
which is not at all the same thing as the deliberate addition of
tin, in connection with which the Royal Commission on Arsenical
Poisoning, so long ago as 1903 reported that
"Chloride of tin appears to us an objectionable and unnecessary
addition to sugar and we are of opinion that it should no
longer be used."
It is, I believe, contended by the manufacturers that the addition
of tin to this class of sugar is necessary. The matter has been brought
to the notice of the Minister of Health, and I understand that it is
being carefully considered by the Minister. The finding of tin in
sugar, of lead or tin in canned fish, of traces of copper in pickles and
like products, and of various other metals in other foods, renders it
necessary to determine these small quantities of metals in a wide
variety of products in addition to examining them for preservatives
and ascertaining their composition in the ordinary way. Thus, the
amount of work which has to be done in examining samples constantly
tends to increase.