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52
report of the Borough School Medical Officer for 1956.
(d) In May an outbreak of food poisoning was reported from a
secondary modern school. At least three adults and 32 children
were involved. The meal comprised boiled boned mutton, vegetables
and gravy, Bakewell tart and custard, the causal organism
being Cl. welchii.
Dr. Betty Hobbs, of the Central Public Health Laboratory,
Colindale, carried out a series of investigations and experiments
and advised as follows:—
"As it seems fairly certain that a proportion of meats are
reaching canteens already contaminated with heat-resistant Cl.
welchii, then measures to protect consumers against this hazard must
be taken.
"Such measures may be described as follows:—
(1) Cook the meat in such a way that all heat-resistant spores
are destroyed, i.e., by pressure cooking or by the thorough
roasting of small-sized joints.
(2) Cook, cool rapidly and maintain in the refrigerator until
required.
(3) Cook and keep hot above 60°C. either inside a hot-plate
or in the steamer when the presence of gravy should make
little difference.
"The same recommendations should apply to gravies and stews.
"The results of our experiments in the School Kitchen are of
much practical use and we are most grateful for the willing help of
all concerned."
(e) In October the parent of a girl attending a High School,
and as a result of a food hygiene lecture attended by the parent
some two years previously, reported that her child appeared to be
suffering from food poisoning. The investigation showed that 52
persons were affected on the Friday but were all back at school on
the Monday except for the child referred to above. 233 persons had
eaten at the first sitting, the meal consisting of cold roast pork,
salad, chocolate pudding and sauce. Contrary to instructions, the
meat was eaten on the day following cooking although stored in
a refrigerator overnight. Bacteriological proof was obtained in two
cases and all symptoms and signs pointed to Cl. welchii, infection ;
the organism was untypable. Again, contrary to instructions, the
sample meal which should have been retained over the week-end,
was thrown away before examination could be carried out.
In addition to the 42 "notified" cases there were 106 "ascertained"
cases, i.e. a total of 148.
The following information is in the form required by the