160
ROBINA B. SCHOLES AND J. M. SHEWAN
The aerobic flora of tho intestincs of fish appears to be rather
similar in character to that of the slime. As might be expected, however, there are more of the facultative anaerobic species such as the
vibrios and some pseudomonads and of the strict anaerobes, such as
clostridia. The latter arc never present in the slimo and members of the
Enterobacteriaceae (e.g. E. coli, and Salmonelkt spp.), so constantly a
feature of the intestinal flora of warm-blooded animals, are absent in
fish except when caught in polluted waters (Shewan, 1962a). An
important member of the Clostridium group, sometimes encountered in
marine as well as in freshwater fish, is Cbstridium botulinum type E and
several cases of food poisoning have arisen from the ingestion of fish,
more particularly in the form of salted or fermented products and eaten
uncooked (Shewan, 1962a ; Dolman, 1960). This organism, which has
several interesting properties such as low minimum growth temperature
(3*8*C), good growth in sea water medium, and production of very heat
labile sporcs, appears to be restricted to northern latitudes and to
waters receiving drainage from large land masses (Dolman, 1960).
Thus, the organism has been found in the sea muds off north-west
Canada, in the Baltic, in the Caspian Sea, and in the Great Lakes area
of North America, but so far it has not been detected in either the muds
or fish in the North Sea, The most recent incidents of botulism,
which caused nineteen deaths, occurred from the ingestion of hot
smoked vacuum packed cisco trout, prepared in the Great Lakes area
of U.S.A. (Ager and Dolman, 1964) distributed unchilled a t ordinary
temperatures and eaten without any further cooking or heat-treatment.
Although this product has been marketed for more than 75 years it is
only recently with the advent of vacuum packaging together with the
production of a commodity having lower salt and higher moisture contents, i.e. conditions more likely to favour the growth of anaerobes, that
cases of botulism have occurred. As a result of these incidents rigorous
instructions concerning the handling and transport of vacuum packs of
these and similar products have been issued by the Food and Drug
Administration in U.S.A. The Canadian Department of Fisheries
banned completely the production or importing of any packaged fish.
Since the organism fails to grow at temperatures below 3"C, proper
storage of these products from the point of production during distribution and until consumed should climinatc any food poisoning hazards.
2. Spoiling fish
So far we have been discussing the floras of new caught fish and it is
of interest now to consider the changcs in these floras occurring during
spoilage. It is proposed to confine these remarks to the spoilage of whole
ROBINA B. SCHOLES AND J. M. SHEWAN
The aerobic flora of tho intestincs of fish appears to be rather
similar in character to that of the slime. As might be expected, however, there are more of the facultative anaerobic species such as the
vibrios and some pseudomonads and of the strict anaerobes, such as
clostridia. The latter arc never present in the slimo and members of the
Enterobacteriaceae (e.g. E. coli, and Salmonelkt spp.), so constantly a
feature of the intestinal flora of warm-blooded animals, are absent in
fish except when caught in polluted waters (Shewan, 1962a). An
important member of the Clostridium group, sometimes encountered in
marine as well as in freshwater fish, is Cbstridium botulinum type E and
several cases of food poisoning have arisen from the ingestion of fish,
more particularly in the form of salted or fermented products and eaten
uncooked (Shewan, 1962a ; Dolman, 1960). This organism, which has
several interesting properties such as low minimum growth temperature
(3*8*C), good growth in sea water medium, and production of very heat
labile sporcs, appears to be restricted to northern latitudes and to
waters receiving drainage from large land masses (Dolman, 1960).
Thus, the organism has been found in the sea muds off north-west
Canada, in the Baltic, in the Caspian Sea, and in the Great Lakes area
of North America, but so far it has not been detected in either the muds
or fish in the North Sea, The most recent incidents of botulism,
which caused nineteen deaths, occurred from the ingestion of hot
smoked vacuum packed cisco trout, prepared in the Great Lakes area
of U.S.A. (Ager and Dolman, 1964) distributed unchilled a t ordinary
temperatures and eaten without any further cooking or heat-treatment.
Although this product has been marketed for more than 75 years it is
only recently with the advent of vacuum packaging together with the
production of a commodity having lower salt and higher moisture contents, i.e. conditions more likely to favour the growth of anaerobes, that
cases of botulism have occurred. As a result of these incidents rigorous
instructions concerning the handling and transport of vacuum packs of
these and similar products have been issued by the Food and Drug
Administration in U.S.A. The Canadian Department of Fisheries
banned completely the production or importing of any packaged fish.
Since the organism fails to grow at temperatures below 3"C, proper
storage of these products from the point of production during distribution and until consumed should climinatc any food poisoning hazards.
2. Spoiling fish
So far we have been discussing the floras of new caught fish and it is
of interest now to consider the changcs in these floras occurring during
spoilage. It is proposed to confine these remarks to the spoilage of whole