Comparative microbiological analysis of raw fishes and sun-dried fishes collected from the Kawran bazaar in Dhaka city, Bangladesh

Abstract

Along with the raw fishes, dry fishes also have a huge contribution to meet up the demand of protein in our daily meal. The assay of microbiological quality is therefore needed to ensure the public health safety. The present study was emphasized on the existence of pathogenic bacteria in raw and dry fish. A total of 50 samples of raw fishes and sun-dried fishes was accumulated aseptically for microbiological quality analysis. Isolation of bacteria was done by spread plate method. All the samples including both (raw and dry) fishes harbored bacteria and fungi up to 106 CFU/g. E. coli was found in all samples as a specific pathogen. In case of raw fishes total viable count (TVC) and total coliform count (E. coli) were recorded up to 2.5x106 CFU/g and 5.2 x104 CFU/g respectively whereas a significant load of Salmonella spp. was observed in almost all samples. Staphylococcus spp. and Pseudomonas spp. were present up to 5 x102 CFU/g and 1.8 x 102 CFU/g respectively. Likewise, total viable count (TVC), total coliform count (E. coli) and fungal load were recorded in dry fish up 3.50 x 105 CFU/g, 1.2 x103 CFU/g respectively. Fungal growth was observed in all experimental raw and dried fishes. For most of the pathogenic isolates, higher rates of resistance were found against Ceftriaxone, Penicillin, Nalidixic acid, Neomycin. On the other hand, most of the isolates were found to retain higher sensitivity against Imipenem, Ciprofloxacin, Tetracyclin and Amoxicillin. This data suggested that the dry fish harbored fewer bacteria than raw fish and sun drying method is still a useful technique for the preservation of fish.