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2
Food Poisoning.
The day population of the City is estimated to be in the region of 500,000, the majority
of whom take luncheon and/or tea in the City. Only two outbreaks of food poisoning, both
fortunately mild and both connected with commercial canteens, came to my notice during
the year. Details of these are as follows: —
No. 1.
On 14th May, 1953, the Medical Officer of Health of Wallington, Surrey, informed
me that a bank manager employed in the City had been notified as suffering from food
poisoning, and that he suspected some shepherd's pie, consumed at lunch in the bank's
luncheon club on the 13th May, as the source of infection.
On enquiry at the bank, it was ascertained that 24 members of the staff had developed
similar symptoms on the evening of 13th May. These were all members of the staff of one
branch and not all of them had had lunch at the luncheon club. It appeared, therefore,
that the source of infection was at one branch and not at the club, where some 1,300 lunches
had been served on the 13th May and there had been no other cases of illness.
At the branch in question, tea or coffee with buns and butter and cakes are served
during the morning and afternoon from a small kitchen. The food is supplied from the
club but the beverages are made at the branch. It was found that milk was supplied to
the branch kitchen from the club in 10 gallon churns. This milk arrived at the branch
after the morning issue of tea and coffee. It was retained in the kitchen which is small and
has no refrigerator, and used for the afternoon beverages and for the morning issue next
day. On enquiry as to how milk was drawn from the 10 gallon churn, it was ascertained
that a jug was dipped in and withdrawn; there was no ladle with a long strap-handle such
as is commonly used for this purpose. Consequently the milk was contaminated by the
jug and by the hand of the kitchen maid. The milk then stood in the warm kitchen overnight,
providing ideal conditions for the growth and multiplication of organisms.
None of the milk delivered on 13th May was of course available, but on May 15th a
sample of the milk delivered on 14th May, from which milk had been drawn for tea on that
day, and the remainder of which had stood over-night in the kitchen, was submitted for
bacteriological examination. The report of the bacteriologist was that methylene blue was
reduced in less than 30 minutes, and that on the total bacterial count the colonies of
bacteria were uncountable. No specific food poisoning organisms were identified, but this
was not the milk consumed on the day when the infection occurred.
In my opinion the most likely cause of the outbreak was the grossly contaminated
milk. Arrangements have been made for the milk to be kept under proper conditions at
the Club and only supplied to the branch for immediate consumption.
The Sanitary Inspectors engaged in the inspection of catering establishments have been
requested to have this incident in mind and to endeavour to ensure that milk is not similarly
contaminated and then incubated in other kitchens, canteens, cafes, etc.
No. 2.
On Friday, 23rd October, at 4 p.m., 1 was informed that an outbreak of mild foodpoisoning
involving about 40 persons, had occurred amongst the staff of a commercial firm
in the City.
The cases had developed during the night of Wednesday, 21st October, and were
attributed to the luncheon meal served in the staff canteen that day.
The symptoms were abdominal pains and diarrhoea, but no vomiting, coming on from
6 to 18 hours (average 12½ hours) after the meal. Recovery was rapid and complete.
The meal was served between 11.40 a.m. and 2.30 p.m. to about 200 persons, of whom
only one-fifth were affected. These were not in any one batch but had eaten the meal at
different times between noon and 2 p.m.
The meal comprised roast beef, roast lamb, baked potatoes, brussels sprouts, tinned
apricpts, tinned pineapples, custard, blue cheese and biscuits.
The only items which had been consumed by all the cases were potatoes and sprouts,
and the gravy served with the meat course. The beef had been cooked the previous day
and stored overnight in a refrigerator. The rest of the meal had been prepared on the day
it was served.
The only residue of the meal available for examination was some beef and mutton bones
with a little meat attached. These were sent to the City Bacteriologist who reported
that he had not found any pathogenic organisms, but observed that they were not satisfactory
specimens on which to express an opinion. They were, however, all that was available
when we came on the scene.
Samples of custard powder were examined bacteriologically but contained neither
pathogenic organisms nor poisonous chemical substances. The canned apricots and pineapples
appeared to be above suspicion as judged by the condition of the remaining stock
of cans.
Samples of faeces were obtained from the four members of the kitchen staff who
prepared the meal. All were found to be free from pathogenic organisms.
Conditions in the kitchen were generally good and the staff well informed on the hygiene
of food preparation. They all readily co-operated in our investigations.
A number of recommendations for minor repairs and improvements to equipment in
the kitchen were made, and the firm have undertaken to give these prompt attention.
The cause of this outbreak must remain unidentified. There is bound to be a delay
of at least 24 hours between the consumption of a suspected meal and news of any ill effects
reaching us, because symptoms do not develop till the late evening, and it is not till the
middle of the next day that the firm concerned realise that an outbreak of food-poisonin
has occurred. In this case the delay was more than 48 hours.