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wards they became sharply ill with abdominal pain and diarrhoea, which
lasted from three to five days, causing considerable worry and inconvenience.
On receiving a report from the doctor, we commenced investigations immediately.
We soon found out that this outbreak in Twickenham was associated
with a similar outbreak in Richmond, where 15 cases had been reported. All
the patients had eaten cream cakes; we soon discovered the infective organism—
the salmonella—in the cream filling of the cakes. The people in the bakery
where the cream came from were all tested for organisms and one of them was
found to be the carrier of a salmonella which exactly matched that in the
cream. This organism can live and be carried in the bowel, often by a person
who exhibits no symptoms. It is conveyed to food on the fingers after using
the toilet, especially when the hands have not been washed afterwards. In this
outbreak the cause was discovered quickly so that further spread to other
people was promptly stopped. Had it not been so the effect could have been
much more serious.
In the second outbreak four people ate a cream layer cake which was infected
by another organism—the staphylococcus—which causes food poisoning
through the toxin it is able to form in the food as it multiplies. The symptoms
are usually more rapid in their onset than in the case of salmonella and resemble
a violent attack of seasickness lasting one or two days. Prompt measures were
taken to deal with the source of infection.
In the third outbreak 39 children from an infant school became ill one day
with symptoms resembling food poisoning. We were able to prove that the
meat eaten by 30 of them was infected with the staphylococcus and its toxin,
but it remained a curious fact that the other nine children who had similar
symptoms had not eaten the infected meat. We were not able to demonstrate
with certainty what the cause was in their case. In two other outbreaks we
were not able to prove with certainty what the causative organism was. This
was also so in 17 individual cases which we investigated.
Thus in spite of much investigation, assisted by excellent laboratory techniques,
there still remains a high proportion of patients who exhibit the
symptoms resembling food poisoning but in whom the cause is undetermined.
There has recently been an outbreak of an illness affecting people all over the
town, lasting two or three days and resembling food poisoning, but no food
poisoning organisms have been isolated. It is clearly infective, spreads from
person to person, and appears to have an incubation period of about five days.
It may possibly be that this illness is caused by a virus like the one which causes
influenza, but there could be other agents.
Chemicals in Food.
Sir Edward Mellanby, in an article in the British Medical Journal, has
called attention to the great expansion in recent years of the practice by the
food industries of adding substances to food which are foreign to the body and
sometimes harmful. These substances improve the appearance of food and so
please customers, but they often at the same time lower the nutritional value
and may sometimes produce a toxic effect. These unnatural chemicals are
added to food in order to save fat, to facilitate emulsification, as preservatives,
as sweetening, as flavouring and colouring agents, and as improvers and
bleachers of flour; also to washing-up water and as sterilisers for utensils;
and to kill insects and control pest and fungus diseases in the food industries
and agriculture.
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