Microbial Assessment and Health Risks of Consumption of Uncooked Smoked Horse Mackerel Fish (Trachurus trachurus) Sold in Open Markets in Owerri Metropolis, South Eastern Nigeria

Aim: To assess the microbiological quality of uncooked smoked horse mackerel fish (Trachurus trachurus) sold in Owerri and ascertain the presence and prevalence of microorganisms of public health importance.

Study Design: Random sampling was done.

Place and Duration of Study: Department of Microbiology, Federal University of Technology, Owerri; from October, 2019 to April, 2020.

Methodology: Smoked fish samples (n=20) were purchased randomly from retailers in Relief, Naze, Eziobodo and Obinze markets and taken to the laboratory for isolation and identification of microorganisms. Standard microbiological methods were employed to analyze for viable heterotrophic bacterial and fungal counts on nutrient agar and potato dextrose agar respectively, using the spread and streak plate techniques. Coliform counts were done on MacConkey agar. Biochemical characterization of the microorganisms was adopted for their identification.

Results: Bacteria identified included Staphylococcus, Escherichia, Proteus, Salmonella and Micrococcus species. Total heterotrophic bacterial counts and coliform counts ranged from 2.8 x 106 cfu/g to 1.6 x 108 cfu/g and 2.7 x 104 cfu/g to 5.3 x 105 cfu/g respectively. Fungal species identified were Penicillium, Rhizopus, Mucor, Aspergillus and Fusarium spp and fungal counts as high as 4.5 x 105 cfu/g were recorded.

Conclusion: The high level of microbial contamination of the samples and the presence of organisms of public health importance signifies an obvious danger to human health. Eating smoked fish without proper cooking should be discouraged by the relevant authorities. Also, food safety authorities should intensify their monitoring efforts towards controlling such contaminations and averting possible outbreaks of diseases.