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Food Inspection.
The total amount of meat delivered at Smithfield Market was 273,736 tons, which was 63,721
tons less than in 1950. Two hundred and thirty-three tons were found by the inspectors to be unfit
for human consumption and were voluntarily surrendered.
At riverside wharves and premises in the City, 167 tons of various foodstuffs were condemned as
unfit for human consumption. In addition, 112 tons were placed under stop and subsequently
released to be dealt with under the supervision of other local authorities.
Every effort is made to ensure that food which is unfit for human consumption is utilised in some
other way, but there is always a quantity, particularly of vegetables and fruit, for which no use can
be found. Considerable trouble arose by reason of the unsound condition of consignments of canned
ham from several continental countries. In many cases the unsoundness was obvious on external
examination of the cans ; in others it was not apparent till the cans were opened, and in some not
until the ham was cut through and the centre examined. It appeared that, because of the good market
for ham in this country, many continental firms embarked on the canning of hams without experience
and without appreciating that the successful canning of large hams is by no means easy. It is
necessary to get just the right degree of curing and just the right temperature in the centre of the
ham to achieve commercial sterilisation (i.e., the destruction of all organisms likely to cause spoilage),
without spoiling the texture and flavour of the meat. The circumstances were reported to the Ministry
of Food, who received similar reports from other districts and from Port Health Authorities.
Food Poisoning.
No formal notification of a case of food poisoning was received during the year, but your Medical
Officer was informed of two extensive, but mild, outbreaks in commercial canteens by the business
houses concerned. There are probably many cases of this mild type of food-poisoning which are never
formally notified because no doctor is called in. The symptoms are abdominal pain and diarrhœa of
varying degrees of severity, there is no vomiting, they occur in the late evening or during the night,
some 6 to 18 hours after a luncheon meal, and by the next morning the symptoms are beginning to
abate and the patients decide that it is unnecessary to seek medical advice. As individuals they
escape detection, unless it happens that a number are employed at the same place of work and have
their mid-day meal at the same canteen; in which case they exchange news of their troubles and
may subsequently complain to the canteen manager; or some of them may be late on duty or even
be away from work for a day, and then the management makes enquiries and communicates with
the Medical Officer of Health.
By this time some twenty-four hours or more have elapsed since the suspected meal was eaten.
The practice is to get a complete menu of the meal, and ask each person who has suffered to mark
the items of which he or she partook. Since nearly all the patients are in the building, the particular
food or foods common to all who were ill are quickly identified. Some of these items can be ignored
as most unlikely sources of infection, and probably the responsibility can be fixed with a fair degree
of certainty on one single item. Unfortunately there is rarely any of the suspected food remaining for
examination. The origin of the suspected food, its subsequent history and details of its treatment
before it was served are carefully traced. At the same time the canteen staff are interviewed by the
Medical Officer of Health, and efforts are made to obtain specimens of faeces from any who may have
infected the food. In some cases rectal swabs have been taken, but it is not easy to persuade canteen
staff, most of whom are women, to collect and bring samples of faeces or to submit to the indignity
of rectal swabbing. It is easier for these samples to be obtained in the homes of cases or suspected
carriers, and in several instances local Medical Officers of Health have kindly acceded to requests to
undertake the necessary investigations.
The kitchen and ancillary rooms are carefully inspected, and the opportunity is taken to emphasise
the importance of food hygiene.
Perhaps the most important departure from good standards of food hygiene is the practice of
cooking the main dish the day before and warming it up on the day it is served. It is easy to criticise
this practice, but in central London at least, the staff do not live close to their place of work, and when
they arrive in the morning they are busy preparing to serve lunch at noon, so it is not always possible
to cook the main dish in the time available. It is therefore often cooked in the afternoon and stored
overnight. If this must be done, the conditions of storage are of vital importance. If they are
unsatisfactory, the food remains for some 15 hours at temperatures suitable for the growth and multiplication
of organisms which have escaped destruction by the heat of cooking, with the result that
a toxic dose of organisms and their products may be served at luncheon next day. It is essential
that the cooked food should be cooled rapidly and kept cool till it is reheated shortly before it is to
be eaten. In canteens the total bulk of the cooked food is large and cooling is a slow process unless
either it is divided into relatively small portions which will cool rapidly, or there are special means
for rapid cooling before it is stored over-night in a refrigerator or cold room.
In domestic cooking the bulk of meat dishes is small, consequently heat penetrates more
thoroughly and sterilisation is therefore more complete, and also subsequent cooling is quicker.
Consequently time and temperature conditions are less favourable for the multiplication of any
organisms which survive the cooking process. This is one reason why food poisoning is more common
in canteens and restaurants and in connection with large parties, than in ordinary feeding at home,
and why high standards of food hygiene must be more strictly observed in such places and on such
occasions.
I am indebted to Dr. Betty Hobbs, of the Central Public Health Laboratories, for informing me
that symptoms of food poisoning such as I have described may be caused by heat-resistant strains of
Clostridium welchii.
It seems possible that such organisms may gain access to the meat at any stage from the
slaughterhouse to the kitchen, and it may be that we sometimes blame the kitchen, when the fault
is really in the slaughterhouse or in the transport and handling of the meat before it reaches the
kitchen. Even if the symptoms of this type of food poisoning are comparatively mild and transient,
they occasion pain, discomfort and anxiety, with the loss of a night's sleep and possibly a day's work
to a large number of people. They cannot, therefore, be passed over as unfortunate incidents which
are unavoidable. Standards of hygiene in relation to meat should be raised all along the line; clean
kitchens and clean cooks are not enough.