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THE STRAND DISTRICT, LONDON. 41
Ice-creams are made differently to the custard ices; fresh
cream is flavoured, and frozen.
On the 24th of August the following samples were obtained,
viz.—
From street-barrow A, custard-ice A.
„ „ A, washing-water A.
From low-class shop B, custard-ice B.
„ „ B, custard B (while cooling).
From street-barrow D, washing-water D.
From good-class shop C, cream-ice C.
Each sample was taken in a sterilized glass-stoppered jar,
under the direction of Dr. J. Wilkinson (of the Bacteriological
Laboratory, King's College), who kindly reported upon them.
A general microscopic examination revealed no foreign matter
in the ices or custard beyond some indefinite undetermined
debris. Growth on gelatine plates and on other media showed
that the ices contained per cubic centimetre from a quarter of a
million to over one and a half million organisms, and some 18
varieties of them were isolated and identified. In the water in
which the glasses and spoons were washed the number was so
numerous that they could not be counted.
Dr. Wilkinson points out that as raw milk may contain from
three to four million micro-organisms per cubic centimetre, and
raw cream may have as many as ten million, a cream-ice,
without further contamination, may contain an enormous number
of organisms derived from the original milk or cream which are
not killed by freezing. With custard-ices, however, the case is
different, as the boiling to which the milk is subjected destroys
the organisms; thus the sample of custard taken while it was
cooling showed only 500 organisms, while some, after it had
cooled and been frozen, taken from the same shop, contained
1,250,000 per cubic centimetre.
Such contamination is easily preventable. It may arise from
any of the following sources :—
1. Dirty vessels used in the preparation of the ices; the
pans are stated to be generally washed in cold water, almost
never scalded out.