Determination of metal content in Ethmalosa fimbiata, Pseudotolilthus epipercus, Clupea harengus and Merluccious merluccious stored in commercial cold stores

Abstract

The levels of some metals (Fe, Cr, Ni, Zn, Cu, Mn, Cd, Pb and Ar) in four different species of imported frozen fish; Atlantic Herrings (Culpea harengus), Merluza (Merluccius merluccius), Bonga (Ethmalosa fimbriata) and Croaker (Pseudotolilthus epipercus) three cartons each of the different species were bought. A carton of each species was kept in three commercial cold-stores in Benin City, Edo State and was investigated for a period of five months during this study. One piece of each species in triplicate were collected every three weeks from these cartons from the three cold stores and transported to the laboratory in coolers with ice to prevent deterioration. Microwave digestion system (Closed Vessels Acid Digestion – MARS System - CEM) procedure based on the organic extraction technique was used for the digestion of all the fish samples, the mineral content was then determined by the use of atomic absorption spectrometer (AAS). Data obtained were analyzed using computer software (SPSS version 22). One way analyses of variance test was used at 5% probability level and DMRT was used to analyze the significant differences between homogenous subsets. Significant differences were observed in the levels of the individual metal in the different fish samples. Levels were compared with safety standard levels set by FAO, WHO and EU legislation for fish and fishery products, and most of the values were within the recommended standards set by FAO, WHO and EU legislation for fish and fish products. However, Ni and Cr were detected at higher levels above the set permissible limits. Fe however was the most accumulated metal in all the fish species. This calls for concern by the relevant agencies and arm of government because of the attendant health implication if consistently consumed due to bio-accumulation of metal in man