Comparative microbiological assessment of export oriented fishes and locally marketed fishes

Abstract

The present study was conducted for comparative microbiological assessment of export oriented fishes locally marketed fishes. For microbiological assessment five species of fish were selected. These were-Magur (Clarias batrachus), Mola (Amblypharyngodon mola), Pabda (Ompak pabda), Rohu (Labeo rohita) and Koi (Anabas testudineus). These species were selected because of their high demand in export market and popularity in our country. This study was conducted because the microbiological status of these fishes could be a major public health issue. Fish samples were collected from four fish processing plants, four local fish markets and four super shops. The present study was designed to assess Satndard Plate Counts (SPC), Total Coliform Counts (TCC) and Total Fecal Coliform Counts (TFC) and qualitative analysis of Salmonella spp. and Vibrio cholerae and antibiotic susceptibility test of pathogenic isolates. The study revealed that SPC in fish processing plant samples ranged from 2.70×103 to 4.95×105 cfu/g, TCC from <3 to15 MPN/g and TFC from <3 to 7.4 MPN/g. In samples of local fish markets SPC, TCC, TFC ranged from 2.89×105 to 2.98×107 cfu/g, 15 to 460 MPN/g, 11 to 240 MPN/g, respectively. In fish samples of super shops SPC, TCC, TFC ranged from 5.96×104 to 5.16×106 cfu/g, <3 to 240 MPN/g, <3 to 120 MPN/g respectively. Among all the fish samples of fish processing plants, local fish markets and super shops, the highest value of SPC was found in Koi fish sample of local market-4 and the lowest value in Mola fish sample of processing plant-2 while TCC was found to be highest in Koi fish samples of local fish market-1 and Pabda fish sample of local fish market-2 and lowest in several fish samples of processing plants and in two fish samples of super shop-1. The highest value of TFC was observed in Koi fish sample of local fish market-1 and Mola fish sample of local fish market-3 whereas the lowest value was found in most of the fish samples of fish processing plants and in two fish samples of super shop-1. Salmonella spp. was detected in most of the samples of local fish markets and few samples of super shops and only two samples of fish processing plants were found to be contaminated with Salmonella spp. Vibrio cholerae was absent in all fish samples of fish processing plants and five samples of local fish markets and three samples of super shops were contaminated with this organism. The bacterial load of fish processing plant samples was almost within the acceptable limit. In this study, the mean value of SPC, TCC and TFC in most of the fish samples were significantly different (p<0.05) among fish processing plants and local fish markets, fish processing plants and super shops, but in case of some fish samples there were no statistically significant difference in mean value of SPC, TCC and TFC among local fish markets and super shops. The study also revealed that the isolated Salmonella spp. and V. cholerae showed antibiotic resistance and sensitivity to seven antimicrobial agents. Most of the isolates were sensitive to chlorampenicol, tetracycline and erythromycin. The findings of this study indicate that the fish samples of fish processing plants were of good quality for export and consumption, fish samples of local fish markets were more contaminated thus reflects the unhygienic condition of the markets and super shop samples were less contaminated but not as good as fish processing plant samples. The contaminated fish samples could be the potential reservoir for the transmission of pathogenic bacteria causing fish borne disease outbreaks.