Heavy metal content and microbiological quality of Yaji (complex spice mixture) sold within Kano metropolis

Abstract

In recent years, food biosafety has been a priority, as such a study was carried out on the microbiological and heavy metal contents of yaji; a complex spice mixture sold within Kano metropolis. A total of nine yaji samples were purchased randomly in several retail stores within Kano metropolis and compared with 3 samples prepared in the laboratory. The result of the analysis showed that the total aerobic mesophilic count, fungal count and coliform count ranged from 3.35×10⁶ - >3.00×10⁷cfu/g, <1.00×10³ – 9.60×10⁶cfu/g, and 3.6 - >1100MPN/g respectively. Staphylococcus aureus, Escherichia coli, Salmonella, Enterobacter and Klebsiella species were the bacteria isolated while  Fusarium, Rhizopus and Aspergillus species were the fungi isolated from the samples. The counts obtained were higher than the maximum acceptable levels provided by the ISO and FAO. The ranges of the concentration of heavy metals in dry weight were; lead 0.001 – 0.003, nickel 0.001 - 0.005, copper 0.002 - 0.020, zinc 0.105 – 0.223, iron 0.004 – 0.009 g/Kg. The levels of metals found in the samples were within the standard limits approved by WHO. This study showed that the samples were not contaminated with the studied heavy metals but were found to harbor microorganisms, which can pose serious health hazard to consumers. It is therefore recommended that strict hygienic measures should be taken during yaji preparation since the laboratory prepared yaji were less contaminated. Public enlightenment on the dangers of heavy metals consumption should be provided as continuous/routine consumption may result to the bioaccumulation of harmful metals in the body.

Key words: Microbiological, heavy metal, spice, yaji, Kano.