EVALUATION OF HEAVY METALS IN THREE VARIETIES OF SACHET TOMATO PASTE

Abstract

The study titled “Evaluation of Some Heavy Metals in sachet Tomato Paste” was conducted to determine the concentrations of selected heavy metals — Cadmium (Cd), Chromium (Cr), Manganese (Mn), Arsenic (As), and Lead (Pb) — in different brands of tomato paste commonly consumed in Sokoto Metropolis, northwestern Nigeria. The research aimed to assess the safety levels of these products in relation to established international standards and to evaluate potential health risks associated with their consumption.Three tomato paste brands, labeled Sample D, Sample G, and Sample N, were randomly purchased from retail outlets within Sokoto metropolis. The samples were digested using the acid digestion method as described by AOAC (2005) with slight modifications, employing a mixture of concentrated nitric acid (HNO₃), hydrogen peroxide (H₂O₂), and hydrochloric acid (HCl). The concentrations of metals were analyzed using Atomic Absorption Spectrophotometry (AAS). The mean concentrations (mg/L) obtained for the samples were as follows: Cd (0.00077), Cr (0.00943), Mn (0.00210), As (0.01547), and Pb (0.04703). The results revealed that Cd, Cr, Mn, and As concentrations were below the permissible limits set by the World Health Organization (WHO, 2011) and the Food and Agriculture Organization (FAO, 2013), indicating that the products were generally safe for consumption. However, the Pb concentration in one sample (0.0724 mg/L) exceeded the WHO permissible limit (0.05 mg/L), suggesting possible contamination during processing or storage.Statistical analysis showed that the relative standard deviations (RSD%) for most metals were within acceptable limits (<10%), except for arsenic and lead, which exhibited higher variability. The overall findings indicate that while the tomato paste samples analyzed are largely safe, the elevated lead concentration in one brand poses potential health risks. It is recommended that regular monitoring of heavy metals in tomato paste and related food products be carried out by regulatory bodies to ensure consumer safety and compliance with international food quality standards.