Bingu international conference centre in lilongwe, malawi

In an effort to reduce toxic heavy metal-contaminants in hammer-milled maize /grain flour, mechanical interventions were undertaken to establish strategic measures for reducing the contaminants in the flour for applications in Malawi, Mozambique and Zambia. In pursuit for this objective a series of experiments were conducted that assessed and quantified the toxic metal contents in the flour in comparison with hand pound flour. In this research flour samples were produced by hand pounding using a pestle and mortar in control treatment against two main treatments whose samples were prepared by hammer milling where foundry hammer mill was also compared to artisanal one. In Malawi, two experimental hammer mills (foundry and artisanal) were studied in each of the two districts (Lilongwe and Salima). In Mozambique, only foundry hammer-milling trial, at IIAM in Nampula, was implemented. Furthermore, LB7 hammer mill size was experimented in each country. For the control treatment, Open pollinated variety maize variety (OPV 523), for flour production, was used. The collected flour samples were analyzed by Atomic Absorption Spectrophotometry (AAS) for the metal content in parts per million (ppm) which in turn were compared to the recommended maximum limits. The eight heavy metal elements were targeted and analyzed: Aluminum (Al), Zinc (Zn), Arsenic (As), Cadmium (Cd), Copper (Cu), Lead (Pb), Manganese (Mn) and Iron (Fe). In addition, weight loss of the beaters due to wear and tear as milling progresses, was investigated and recorded. Thereafter, all the flour sample treatments were magnetically metal-scanned. The trend results from both countries confirmed that there is higher heavy metal contents in hammer-milled flour than hand pound samples that could be toxic and cause, significant ill-health to humans, if not checked. Such higher metal contents (whole maize grain “mgaiwa” flour sample) of 28.60±0.80 to 85.24±1.21, 35.60±0.60 to 562.05±4.11 than 0.07±0.1 to 19.18±4.0 ppm for foundry hammer mill, artisanal hammer mill and hand pounding, were achieved, respectively. In terms of weight loss of the beaters, an average wearing rate of 60.48 and 75.02 ppm for foundry and artisanal hammer milling was achieved, after sixty-six days of milling, respectively. In terms of metal scanning, hand pound flour samples achieved no metal traces as opposed to the hammer milling. Comparison of the foundry and artisanal hammer mill, further, showed that artisanal hammer mill contaminates flour much more than foundry milling. In addition, the results also showed that the findings for hammer mills were much higher than the recommended maximum set limits and thus exhibiting high levels of metal contamination and toxicity with