Heavy metals determination and microbial assessment of some species of frozen fish sold at Utako Market, Abuja, Nigeria

Abstract

This work assessed heavy metals [Copper (Cu), Iron (Fe), Cadmium (Cd), Zinc (Zn) and Lead (Pb)] concentrations and microbial load in the tissue (skin, fillet and gills) of some frozen fishes [Clupea harengus (herring), Scomber scombrus (Mackerel), Urophycis tenuis (White hake)] sold in Utako market using Flame Atomic Absorption Spectrophotometer (AAS) and standard microbiological procedures. The results obtained revealed that the concentrations of all the heavy metals determined except Zinc (Zn) were above the Food and Agriculture Organization (FAO) and World Health Organization (WHO) permissible limits in fresh water fish and fishery products. The total aerobic plate count (APC) was between 2.15×103 cfu/g and 47.6×103 cfu/g, total coliform count ranged from 1.85 × 103 cfu/g to 2.03 × 103 cfu/g and fungal counts ranged between 6.02x102 cfu/g and 18.3x102 cfu/g. The microbiological study showed that the skin had more load compared to other studied tissues and in all, the microbial load except APC also exceeded the FAO/WHO acceptable limits for frozen fish products. This study indicated that the products were not ideal for consumption due to bioaccumulation of these heavy metals and the issue of post-harvest contaminants that can multiply in case of defrosting which may impact negatively on the consumers. It is recommended that there should be proper handling and examination of frozen foods and they should be properly cooked before consumption.