Occurrence of Clostridium botulinum in fresh and cured fish in retail trade in Cochin (India).

The occurrence of Clostridium botulinum in fresh (67) and cured fish (278) samples in retail trade in Cochin was studied. An overall prevalence of 19% (13/67) was found in fresh retail fish and types A to D were detected in the positive samples. In pelagic fish, incidence of C. botulinum was 18% (7/39) whereas in demersal fish, 21% (5/24) of the samples harboured C. botulinum. Incidence of C. botulinum in shrimp was 25% (1/4) and type D was found in the positive sample. Of 257 cured fish in retail trade tested for the presence of C. botulinum, the overall contamination level was 10% (25/257). Among the C. botulinum types A to D prevalent in fresh fish, types C and D were the predominant types found in cured products. In salt-dried shrimp, of the 21 samples analysed, 10 samples (48%) harboured C. botulinum.