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The considerations which prompted, this policy were as follows
1. Due to the abnormally hot dry summer the esturial mters and the Shellfish
layings might reasonably be considered more heavily contaminated than
usual.
The normal process of steaming for six minutes, although adequate to deal
with normal contamination, might not be adequate to deal with abnormally
heavy contamination.
2. It ms considered inadvisable to wash the raw cockles in water , which might
be heavily contaminated, until bacteriological tests had been completed.
3. It was generally conceded by the Shellfish Industry that certain gathering
grounds were more likely to be heavily contaminated than others.
The use of these "suspected" grounds was therefore voluntarily discontinued.
4. The possibility that cockles were contaminated after the cooking process was
not overlooked, and more detailed attention to hygiene in the Sheds was
considered the remedy.
Sampling of the cockles, and bacteriological examination at all stages of their
preparation, ms continued in an endeavour to find the cause of the trouble.
The bacteriological examinations indicated that in cockles taken direct from
the cooking pot the edible portion was sterile after six minutes steaming. But
when samples were taken from the first washing tank under the riddle a very considerable
growth of bacteria vjas found in nearly every case. Thereafter the
bacteriological condition of the cockles was found to improve as the cockles were
washed in three and sometimes four changes of cold fresh water. But never again
vie re the cockles found to be sterile.
This lead to further experiments and sampling.
First it was conclusively shown that cockles rapidly lose flavour and
texture and therefore marketability when subjected to steam cooking for periods
in excess of six minutes.
Secondly, although the edible portion of the cockle is sterile after six
minutes steam cookings the outside of the shell and the mud and sand thereon is
found to be not sterile after much longer contact with the steam. It was therefore
evidently necessary first to remove as much sand and mud as possible from
the cockles before they are cooked.
This was done by reverting to washing the cockles in tidal water at the time
of discharge and, in addition, washing them in fresh waster from the town supply
immediately prior to cooking.
Secondly it was necessary to devise an apparatus which would separate the
cooked sterile cockle from the unsterile shell as rapidly and completely as
possible, and which would at the same time provide for the rapid cooling of the
cooked cockles.
An apparatus for this purpose has been devised and is now being tried experimentally.
It v.as further decided that every Establishment should have some means of
sterilizing their apparatus at the end of each days work, and therefore every
Establishment has been requested to fit a steam sterilizing hose for this purpose.
A paper "Advice on the handling of Cockles at the Cockle Sheds" was circulated
to all members of the Industry, and at a meeting at Leigh on 18th October 1949
the Medical Officer of Health, Port of London, and the Medical Officer of Health,
Borough of Southend-on-Sea, addressed the Shellfish Industry on the food poisoning
epidemic in so far as Shellfish were implicated, and made known their requirements
to prevent similar occurrences in future.
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