Human health risk assessment of heavy metals, and bacteriological analysis of cassava flakes (garri) sold in major markets in Makurdi Metropolis, Benue, Nigeria

Abstract

Today, food safety is a global primary priority determinant, surpassing nutritional quality and cost, in foods choices. Contaminants such as bacteria and heavy metals are regarded as highly disturbing and of primary health concern. This study examines the quality of road side sold cassava flakes in Makurdi. Samples from five major markets were analyzed using Flame Atomic Absorption Spectroscopy, for the respective heavy metals: Pb, Cd, Cr, Ni, Cu and Zn. And subsequently their potential human health risk: Daily intake of metals (DIM), Health risk index (HRI), Target hazard quotient (THQ) and Total target hazard quotient (TTHQ). Plate count bacteriological analysis was employed. In this study, Cd, Cu and Zn were detected in the respective mg/kg ranges; 1.00 - 2.25, 0.25 - 0.75 and 0.50 - 9.00. DIM (mg/kg/person) values for Cd, Cu and Zn were found to be in the ranges of, 0.011 - 0.025, 0.003 - 0.009 and 0.006 - 0.103 respectively. Further analysis showed that only Cd had HRI values > 1. On the contrary, all the metals have THQ and TTHQ values < 1. Bacteriological assessment revealed the presence of Bacillus spp., Klebsiella spp., Salmonella spp., and Proteus spp. in the samples in the percentage prevalence of 51.85, 18.52, 18.52 and 11.11 % respectively. Cumulative bacteria prevalence for Wurukum, North-Bank, High-Level and Wadata and Modern Market were thus; 25.93, 22.22, 18.52, and 14.81 % respectively. With Cd values above threshold limit and the prevalence of these pathogenic bacteria species, potential of metal toxicity, typhoid and Diarrhea outbreaks is imminent.