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appendix vi
Imported Foods and the Nation:
Some Recent Problems
WHEN I was asked whether I would write this
paper, I welcomed the suggestion as affording an
opportunity of explaining some of the difficulties
experienced in the Port of London from time to time, and
their solution by the means that are available at the time.
The action taken is often forced upon us by circumstances
with results that may not always be understood by
colleagues in districts remote from the urgency of port
work.
They may find, for instance, some tons of meat, Salmonella-contaminated,
arriving in their districts for
manufacturing use "at processing temperatures sufficient
to destroy the contaminating bacteria and subject to such
steps being taken as appeared necessary to prevent any
risk of cross contamination within the plant." A medical
officer probably would not know that perhaps 20 other
medical officers were aski ng: why the port health authority
were sending that meat into their district. The reason is
that often there is little time for formal meetings or the
delay of correspondence; decisions must frequently be
made whilst the cargo is being actually discharged.
In addition to the five large dock groups within the
Port of London Health Authority's district, the riverside
wharves in the City of London also come under my
jurisdiction. Within the Port of London there are the
riverside wharves lying within the areas of eight riparian
authorities each of which operates as a port health
authority in regard to imported food.
Imported food falls to be examined in the docks unless
it is discharged overside for H.M. Customs clearance and
examination in the area of a riparian authority. Maintenance
of close liaison is essential between these authorities
to secure uniformity of action throughout the Port, and
between ports, to secure the same uniformity throughout
the country.
The Port of London receives annually food imports
of approximately 1,250,000 tons valued at about
£700,000,000. Of this, meat accounts for 550,000 tons
valued at about £190,000,000. Approximately 50 per cent
of all food imports and 60 per cent of total meat imports
pass through the port.
To have written a paper under this heading even five,
and certainly ten, years ago would have been a simple
task compared with that of today, and it would be
convenient to confine the contents to problems that have
arisen during the last five years.
Previously the sixth sense of the experienced food
inspector told him what to look for and where to look for
it, and with the help of the public analyst, and very
occasionally the bacteriologist, one felt reasonably well
satisfied that a job had been well done, and that little food
not "wholesome for man's body and fit to be sold", as the
Worshipful the Fishmongers' Company aptly puts it,
passed through the ports for distribution throughout the
country.
Today the sixth sense is training itself to discern the
types of food which are liable to harmful bacterial contamination,
and the newly established sources of supply
in which processing techniques and hygienic standards
perhaps lack the benefit of experience in food preparation.
It must be realized that there are limits to the number of
staff available for food inspection and in the facilities of
the laboratories, both analytical and bacteriological, to
examine samples, and at times these limits are somewhat
stretched.
It would be physically impossible for the Port staff to
examine in detail all imported food. The unit of inspection
is, of course, the shipment, with sub units of trade or
establishment marks, and the first problem is the storage,
when necessary, of shipments detained for further and
more extensive examination. The accommodation for
cold storage within the docks, especially in the case of
meat, is insufficient to allow the holding of many shipments
pending reports upon bacteriological sampling,
and it is by co-operation with fellow medical officers of
health that the shipment goes forward under detention
into their area for storage and whatever subsequent
action may be appropriate.
For example, it was not possible recently to undertake
the necessary 100 per cent examination of accumulating
shipments of diseased South American livers at the docks,
and these were siphoned off into the cold stores within the
City of London and Finsbury where facilities exist for the
detailed examination required.
1. RECENT PROBLEMS
The following gives a short account of some of the
recent problems and the manner in which they were dealt
with.
(a) Egg Products
The first introduction to large-scale bacteriological
problems was the finding of salmonella organisms in
Chinese egg albumen. Within a very short time sampling
was being carried out at the rate of 5,000 per year, which
disrupted not only the well-planned allocation of the food
inspectors' time, but also the normal work of the Public
Health Laboratories, resulting in reports being received
up to four and five weeks after submission of samples,
consequent delays in clearance of cargoes, and mounting
shortage of available storage space. Frozen egg products
from Commonwealth and other countries added to the
pressure on the limited cold storage space.
Sampling was carried out on a five per cent basis, any
positive samples necessitating a further 10 per cent
examination which, if yielding further positive reports,
led to the condemnation of the entire shipment. Should
no positive results be obtained from the 10 per cent
sampling, the shipment was released with the exception
of the case or cases giving positive results on the original
five per cent examination.
Experience showed that the distribution of salmonella
was not uniform and that a positive result was quite
likely upon a further sampling of a container yielding
preliminary negative results and vice versa. In fact
experiments were carried out by continuous sampling of
a shipment yielding a low rate of positive samples until
eventually a 100 per cent positive result was obtained
from every container. All egg products were therefore
regarded as suspect, irrespective of negative reports.
Heat treatment was found to be the effective answer to
the problem. Release was given subject to a process of
heat treatment at an approved centre, for high temperature
baking under supervision, or for industrial purposes
not involving human consumption or necessitating a
health hazard through cross contamination of other foodstuffs.
Shipments of egg products are still detained pending
receipt of bacteriological report and salmonella contamination
is still present, the problem being accepted as
inseparable from this article of food.
(b) Tea
With little advance warning, on 1 January 1959, the
examination of imported tea ceased to be carried out by
officers of H.M. Customs and Excise and devolved upon
port health and local authorities.
In London, sampling for analysis by H.M. Customs
had been carried out at a rate of between 3,000 and 5,250
per annum yielding from 0-2 per cent to 2 per cent adverse
reports.
From samples of tea taken by the Port Health Authority
under the Imported Food Regulations and in the City
of London under the Food and Drugs Act it soon became
evident that teas from certain countries, especially
Formosa and Indonesia, contained lead and lead compounds
much in excess of the limit of 10 p.p.m. recommended
by the Food Standards Committee in 1954.
Enquiries have elicited no definite information as to the
source of this metallic contamination, but a suggestion
has been made that it is not unconnected with the
artificial colouring of the tea. The problem was fairly easy
to solve, and blending with lead-free teas in such proportion
that the resulting lead content was well within the
recommended limit was permitted.
A recent shipment of 17 tons of Formosa tea reported
by the Public Analyst as containing 269 p.p.m. lead and
lead compounds was considered unsuitable for blending
and was surrendered for destruction.