An outbreak of disease in a British trout farm was identified as fish botulism. The diagnosis was established by demonstration of toxin in the serum and intestinal contents of fish, and was confirmed by the production of experimental botulism in trout inoculated with toxin from a strain of Clostridium botulinum type E isolated from intestinal contents of a sick fish. The outbreak was controlled and eliminated within 1 month by conservative measures which comprised the emptying, cleaning and heavy liming of affected ponds; intensive examination of all ponds for immediate removal of dead and sick fish and, on public health grounds, the banning of movement of fish outwith the farm. This episode, although of considerable financial consequence to the farmer, was shown to have no public health significance.

The inhibitory effect of nisin on toxin production by Clostridium botulinum type E in inoculated cod, herring, and smoked mackerel fillets, packaged in a 100% carbon dioxide atmosphere, was studied at storage temperatures of 10 and 26°C. Nisin delayed the onset of toxin production in all three fish species. The nisin effect was marked at 10°C and delayed the onset of toxin production by at least 5 d beyond that of the controls. At 26°C the delay was shorter, being one-half day for cod, one day for herring, and two days for smoked mackerel. Nisin did not affect the time to spoilage by nonpathogenic bacteria at either temperatures of storage. It was noted that toxin was formed in untreated cod, mackerel, and herring stored at 26°C and in mackerel stored at 10°C before the samples were judged to be unacceptable to the consumer.

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This paper describes a pilot study undertaken in a major acute trust investigating reduction of bacterial contamination in a healthcare environment attributable to the use of silver antimicrobial (BioCote®) technology. The four month study assessed the impact of various BioCote®-treated products on the counts of viable bacteria cultured from the treated environment compared to a control. A mean reduction in bacterial counts of 95.8% was demonstrated on the BioCote®treated surfaces compared with untreated surfaces. A mean reduction of 43.5% was demonstrated on untreated products positioned in the same environment as BioCote®-treated products compared with control untreated products. This suggests decontamination is not limited to treated materials but can extend to the wider environment because of the presence of antimicrobial materials. In the light of increasing evidence implicating the role of the environment in healthcare acquired infection, the potential of BioCote®-treated products to provide an additional infection control mechanism is highlighted.

The incidence of Clostridium botulinum in farmed trout has been studied. Seventeen farms were visited; 5 in Scotland, 2 in Wales and 10 in England. Fourteen hundred trout were examined and the incidence of Cl. botulinum in whole fish and viscera was 9·4 and 11·0%, respectively. The organism was demonstrated in 13 of the 17 farms examined ranging from 2·9 to 100%. Four visits to one farm showed only a slight variation in the incidence of the organism.