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27
Food Poisoning
Section 26 (1) of the Food and Drugs Act, 1955, requires that if a medical practitioner becomes
aware, or suspects, that a patient whom he is attending within the district of any local authority is
suffering from food poisoning, he shall forthwith send to the Medical Officer of Health of that
district a certificate stating certain particulars which will enable the person to be identified, together
with particulars of the food poisoning from which the patient is, or is suspected to be, suffering.
During the year information was received concerning some 248 persons who were reported to be
suffering from food poisoning. Not all these were notified as such; in fact, most of the incidents
which come to the notice of the Health Department are never officially notified by a medical
practitioner—many who suffer food poisoning, experience only minor symptoms and therefore
do not seek medical advice. It is usually only where the illness assumes a greater severity that a
doctor's aid is sought. In other cases the patient consults his doctor with symptoms appearing to
have resulted from something he has eaten but it is clinically'difficult to identify with certainty an
isolated case of this kind where the duration of the illness is probably short, and where no specimens
are available for examination. It is only by bacteriological examination of specimens from the
patient and, ideally, also of the suspected food taken within a short period following the onset of the
illness that a positive diagnosis is likely to be made. It is unfortunately the experience of Health
Departments that details of symptoms and associated meals are sometimes not received until some
days after the initial stage of the illness has passed. By then any food which might have been
obtained from the suspected meal is no longer available and specimens from the affected person
would be unlikely to provide a clue as to the possible cause. In the investigation of cases of food
poisoning, speed of notification is essential.
A summary of food poisoning investigations made during the year is given in Table 27, page 75,
and the following is a resum6 of incidents involving two or more persons.
A party of three were taken ill with diarrhoea and abdominal pain. Enquiry revealed that one of
them had eaten a meat dish at a restaurant some two hours prior to the onset of her illness. The
other two had not actually had the same meal, but had 'tasted' the dish of their companion, and were
subsequently ill. Heat resistant Clostridium welchii was isolated from a specimen of one patient,
and also from meat specimens taken subsequent to the outbreak.
Three persons were ill after consuming a Bolognaise sauce as part of a meal at a restaurant.
Specimens of the sauce were found to contain Clostridium welchii organisms.
Five employees at local business premises suffered diarrhoea and stomach pain about 12 hours
after a canteen meal which included pasties. Clostridium welchii was isolated from a pasty and
also from specimens of two of those affected. The pasties consumed were brought from the
West Country by road uncooked in refrigerated containers. It was not possible to determine when
the growth multiplication of organisms producing the toxins which were the cause of illness took
place; it could have been at the factory or at the canteen premises. Further samples of pasty
from subsequent deliveries submitted for bacteriological examination produced a negative result.
The Medical Officer of Health for the area where the pasties originated was fully informed of this
matter but investigations which he made at the factory revealed nothing to account for the occurrence.
Seventy-five persons were taken ill after a function at a restaurant but the episode only came to
the notice of this Department some 10 days later. The symptoms suggested Clostridium welchii as
the probable cause and, chicken having been served to the party concerned, investigations were
made at a subsequent banquet where the same dish was being offered. Bacteriological examination
of specimens of chicken taken immediately prior to service disclosed the presence of Clostridium
welchii and it was revealed that whilst the normal practice was to prepare and cook the chickens
at 10 a.m. on the day of service, and after cooling place them under refrigeration, on the day of the
function concerned the quantity used had exceeded the refrigeration space available, and the
chickens had been left in an unfavourable temperature which had permitted the growth of organisms
and the production of harmful toxins.
It may be of interest to mention that Clostridium welchii is a toxin producing spore bearing
organism which lives in the intestines of animals and man. It is sometimes found in meat as a
result of contamination occurring either before (the spores of the organism are heat resistant)
or after cooking, and its presence produces no detectable change in the meat. The danger arises
when this meat is allowed to cool slowly, or is kept in a warm kitchen or preparation room for any
length of time, or is warmed up later, or is subjected to a combination of these conditions. The
spores will then germinate and the resulting organisms grow rapidly and produce a corresponding
amount of toxins. It follows that meat should either be cooked and immediately eaten hot, or cooled
rapidly and refrigerated within one and a half hours until required.