Microbial Diversity and Heavy Metals Concentration of Wood Smoked Fish from Edonwhii Fishing Settlement in Akwa Ibom State, Nigeria

Abstract

The microbial diversity and heavy metal concentrations of wood smoked fishes (Clarias gariepinus and Pseudotolithus elongatus) from Edonwhii fishing settlement in Akwa Ibom State, Nigeria were investigated using standard microbiological protocols and analytical procedures, to ascertain the level of fish contamination. The study revealed variations in the densities of the different microbial groups. The fresh fish samples of Clarias gariepinus and Pseudotolithus elongates had Total heterotrophic bacterial count of 7.1 x 105 and 4.1 x 107 cfu/g respectively as compared to the smoke-dried fish which had 4.8 x102 and 6.7 x 102 cfu/g respectively obtained 16 hours after smoke dying. The study reveals a rich microbial assemblage of the fish samples. Streptococcus sp, Salmonella sp, Shigella sp, Escherichia coli, Vibrio cholerae and Bacillus sp. were the different bacteria isolates encountered in the study while Absidia sp., Candida sp., Penicillium sp., Cladosporium sp., Aspergillus sp., Trichophyton sp., Torula sp., Saccharomyces sp., Verticillium sp. and Mucor sp were the fungal isolates identified. The metal analysis result showed that Zn was found to be the most abundant metal. However, Cd levels in Clarias gariepinus (0.23 mg/kg) was relatively higher than the value recorded for Pseudotolithus elongatus (0.16 mg/kg) but all were within the FAO/WHO permissible level of (0.5 mg/kg) of Cd in sea food. Similarly, the Pb levels were within the FAO/WHO permissible level of 0.3 mg/kg, indicating that the smoked fish samples were still suitable for human consumption.