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The term "bacteriological food poisoning" is used by public health workers to describe outbreaks
of illness characterised by nausea, vomiting and diarrhoea, sometimes associated with
fatal results, caused by the consumption of food or drink contaminated by germs belonging to a
family or type known as the Salmonella Group. Bacteriologists have not much difficulty in discovering
the presence of the Salmonella Group of organisms in infected foodstuffs and bowel
discharges, but it is a highly technical and painstaking proceeding to differentiate the various
members of the family.
Food animals may be infected with these organisms during life, and in the process of slaughtering
the contents of the bowels may escape and contaminate the flesh, with the result that the infection
may be conveyed to human beings who eat the meat.
During preparation for consumption, meat foodstuffs may be contaminated in the factory
or in the home with organisms of the Salmonella Group.
Course of the Outbreak.
Information was received in the Public Health Department that persons in three different
Boroughs had been taken ill and were suffering from abdominal pains, sickness and diarrhoea after
partaking of meat pies which had been purchased from a shop in the Borough of Kensington. Later,
other persons residing in different districts were reported to be suffering from similar symptoms
after partaking of pie obtained from the same shop. Altogether 20 persons were reported to be
suffering from symptoms suggestive of food poisoning. In every case pie obtained from the same
shop had been eaten and the interval between the consumption of the pie and the onset of the
symptoms was approximately the same in all cases. Only one person was known to have eaten
the pie without falling ill.
Medical men are not required by law to notify persons suffering from food poisoning; and,
therefore, it is possible that there were other cases. Of these there is no evidence; but the facts
stated are sufficient to justify the conclusion that the pie was responsible for the outbreak.
The attack of illness was acute and in several cases quite severe, but all the patients recovered.
Bacteriological Investigation of the Outbreak.
With the help of other Medical Officers of Health and general practitioners, specimens of bowel
discharges were secured from all the patients except three.
The specimens were examined by the Council's bacteriologist, who discovered in every instance
an organism belonging to the Salmonella Group. Duplicate specimens were sent to the Ministry
of Health bacteriologist, and the examinations made by him gave similar results. Much difficulty
was experienced, however, in recognising which particular organism it was. Eventually, after
the epidemic had subsided, it was discovered that the organism was a member of the third or
diphasic series of the Salmonella Group, and was of the type named "Thompson." This bacillus
has been isolated in at least four other outbreaks of food poisoning.
As the illness appeared so soon after the consumption of the pie, it was fortunately possible
to secure portions of uneaten pie from the homes of three of the patients. The unconsumed pie
was examined by a private bacteriologist, the Ministry of Health bacteriologist, and by the Borough
bacteriologist. In each case an organism of the Salmonella Group was discovered and at a later
stage it was proved to be the B. Thompson. Thus, the germ found in the discharges of the patients
was also found in the pie.
Epidemiological Investigation of the Outbreak.
Inspections were made of the premises where the pie was baked, stored and sold but no fault
could be found in regard to the general sanitary conditions. There had been some trouble from
rats and mice in neighbouring premises. It was thought that there might have been some
migration of the vermin, and attempts to catch rats were made, but were unsuccessful.
Three mice were trapped and one rat was caught in the neighbourhood. These four rodents
were submitted to exhaustive examination by the Council's bacteriologist, but no evidence of
the presence of organisms of the Salmonella Group was discovered.
All persons handling the pies were medically examined immediately the circumstances were
brought to notice and on subsequent occasions. It was discovered that a woman pie-maker had been
absent from work for two days, and had submitted a medical certificate stating that she had suffered
from influenza. It was ascertained that during her absence she had suffered from diarrhoea and
vomiting. Specimens of her faeces and urine were taken and in each case the bacteriologist discovered