Effect of Milling Equipment on the Level of Heavy Metal Content of Foodstuff

Abstract

Aims: This study evaluated the concentration of heavy metal contamination of foodstuff by selected milling equipment (burr mill and hammer mill). Place and Duration of Study:  Samples collected from a market in Akungba-Akoko Southwestern Nigeria; processed and analysed at Prof. Julius Okojie Central Research laboratory, Federal University of Technology, Akure, Nigeria between January and April, 2018. Methodology: Selected food samples (yam, plantain, wheat, guinea corn, beans, soya beans, maize and cassava) were sourced randomly from a local market in Akungba-Akoko, Ondo       State, washed with distilled deionised water, sun-dried and milled into their resulting flour   product; a corresponding acid digested sample served as control. Heavy metal analysis of copper, iron, lead, cadmium, chromium and zinc were carried out using atomic absorption spectrophotometry [AAS]. Results: Results revealed that of the milling equipment used in this study, the burr mill introduced the maximum concentration of contaminant into food, while the hammer mill recorded level of contaminant in minimal doses. Fe was predominant in all the milled samples; the metallic composition of the mills being a contributory factor to the level of contamination. Cd was below the detection limit in the analysed samples. Pb and Cr were found to be comparatively higher than the permissible limit of 0.3mg/kg and 2.3mg/kg respectively recommended by WHO/FAO. The concentration range of Cu and Zn were within acceptable limit and presents no risk of intake. Conclusion: The higher concentration level of metals recorded in the milled samples in comparison to the control shows a level of contamination introduced by the mill.