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8
The Ministry of Health has devised a bacteriological standard
which enables a fairly accurate picture to be formed of the cleanliness
of ice cream, and in their Bulletin for March, 1947, it is
stated that for the purpose of assessing bacterial cleanliness ice
cream samples should be placed in grades 1, 2, 3 or 4, according
to the Methylene Blue Reduction Test, which gives a reduction
according to the bacterial cleanliness. It is further stated that
this grading affords a good index not only of general bacterial
contamination, but also of the degree of presumably excretal
contamination of ice cream.
Although the Ministry of Health Circular 69/47, issued with
the Ice Cream (Heat Treatment, etc.) Regulations, 1947, states,
that these gradings are at present provisional, there can be no
doubt that any ice cream which contains excretal contamination
may be potentially dangerous since this form of contamination
is associated with enteric fever epidemics and possibly with
poliomyelitis (infantile paralysis) infection.
The bacteriological reports on ice cream samples are, on the
whole, so unsatisfactory, both as to the bacteriological gradings
and the presence of the bacteria known as faecal coli (which is
derived from the intestines), that when it is remembered that only
a tiny fraction of the ice cream eaten is sampled, the total amount
of unsatisfactory ice cream consumed must be enormous.
A summary of the replies received to a questionnaire circulated
to all the Metropolitan Boroughs in September, 1948, lends
support to this view, for it showed that throughout the whole of
1947 only 181 of 1,328 samples of ice cream taken in the county
were in grade 1, and there were 709 in the lowest grades, 3 and
4, which are regarded as unsatisfactory. In 1948, from the
1st January to the 31st August, only 491 of 1,792 samples taken
were in grade 1 and 857 were in grades 3 and 4. Of a total of
47 samples taken in Hackney during 1948, only 7 were in grade 1,
and 34 were unsatisfactory.
It is obvious from these figures that most of the ice cream
consumed does not reach a satisfactory standard of bacteriological
cleanliness, a fact which is further emphasised by the appearance
from time to time of faecal coli in the samples taken, and in this
connection the following extract from the "Medical Officer"
published on the 10th September, 1949, makes interesting reading:
"The virus of polio has been proved to be discharged in
the faeces of convalescents and the virus has been
proved to be conveyed by flies from infected fæces on