The knowledge of fish and associated biochemical activity, likely to cause spoilage of the fish is paramount; and most of the fishes consumed by Nigerians are imported. Thus, there is a need to investigate the biochemical qualities of imported frozen fishes. This study was aimed to determine the biochemical qualities of three imported frozen fish species sold in Zaria, Nigeria. The biochemical qualities assessment of the fishes was conducted according to the methods of Riquixo (1998), Undeland et al. (2005) and Vyncke (2006). The result in Sardina pilchardus, Trachurus trachurus and Clupea harengus, showed a significant difference. This study revealed that total volatile nitrogen, thiobarbituric acid and peroxide value mean concentrations of 22.87, 1.94 and 4.18, respectively in the three fish species are within the acceptable limit, except trimethylamine amine (12.88) which is not within the acceptable limit. Therefore, the biochemical qualities of imported frozen Clupea harengus, Sardina pilchardus and Trachurus trachurus sold in Zaria is slightly not suitable for human consumption.

In conclusion, TVN, TBA, and TMA concentrations in the three fish species are within the acceptable limit of FAO. Therefore, the biochemical qualities of imported frozen C. harengus, S. pilchardus and T. trachurus sold in Zaria are suitable for human consumption.

Relevant agencies should ensure strict compliance to recommended biochemical limits of frozen fish imported into Nigeria.