Study on the Micro-flora and Chemical Constituents of Preserved Fishes Available in Kathmandu Market

Abstract

Preserved fish are quite popular among the people of Kathmandu. There are many shops in Kathmandu and Lalitpur where preserved fish are sold. These fish are available in four different forms, viz, ice-preserved or chilled, salted, sun-dried and smoked. Chilled fishes include Rohu (Labeo spp.), Carps, Cat fishes etc. Salted fish include Harpadon nehereus, sun-dried fish include Puntius spp., Oxygaster spp. etc. and smoked fish include Naini (Cirrhinus mrigala), Schizothorax spp., Garra gotyla, Tor spp. etc. Most of these fish are supplied from different parts of India such as Andra Pradesh, Bombay while some are brought from different parts Nepal as well. The salted and sun-dried varieties sell in cheaper price than smoked ones. The hygienic condition of fish markets is quite poor which make these fishes susceptible to micro-flora contamination. The micro-flora contamination also depends upon the process followed during the preservation. The bacterial test revealed that in smoked fish (Cirrhinus mrigala) the bacteria isolated are Pseudomonas, Micrococcus and Staphylococcus. In salted fish (Harpadon nehereus) colonies of Enterobacteriaceae spp. such as Salmonella spp. were isolated. Similary, in sun-dried fish (Oxygaster spp.) also species of Salmonella and Escherichia coli were isolated. Besides bacteria the preserved fish were also subjected for fungi culture. Two different types of fungal conlonies were isolated. In sun-dried fish colonies of Trichoderma spp. and Aspergillus fumigatus were isolated. In case of salted fish colonies of Trichoderma spp. are isolated. The chemical analysis of fish revealed that the protein content of Cirrhinus mrigala (smoked fish) is 70.78 percent whereas that of Harpadon nehereus (salted fish) is 62.15 percent. Similarly, the protein content of Oxygaster spp. (sun-dried fish) was found to be 64.93 percent. The fat content of fish flesh is the factor that determines the quality of fish and hence its price. The fat content of smoked fish, Cirrhinus mrigala was highest among the three. It was about 7.23 percent whereas that of Harpadon nehereus (salted) and Oxygaster spp. (sun-dried) were 6.03 and 4.21 per cent respectively.