Heavy metal, microbial and pesticides residue contaminations are limiting the potential consumption of green leafy vegetables in Ghana: An overview

Green leafy vegetables (such as cocoyam (Colocasia spp) leaves, spinach (Spinach spp), amaranths (Amaranthus spp), roselle leaves (Hibiscus spp), and lettuce (Lactuca spp)) form a major part of Ghanaian meals providing essential vitamin such as A, B and C and minerals including iron and calcium as well as essential bioactive compounds. However, the practices involved in the production, distribution and handling of these nutrient rich vegetables, by most value chain actors in Ghana, unfortunately pre-dispose them to contamination with pathogens, heavy metals and pesticides residues. These have therefore raised public health concerns regarding the safety and quality of these green leafy vegetables. Understanding the current perspectives of the type of pathogens, heavy metals and pesticide contaminants that are found in leafy vegetables and their health impacts on consumers will go a long way in helping to identify appropriate mitigation measures that could be used to improve the practices involved and thereby help safeguard human health. This review examined reported cases of microbial, heavy metal and pesticides residue contamination of green leafy vegetables in Ghana from 2005 to 2022. Notable pathogenic microorganisms were Ascaris eggs and larvae, faecal coliform, Salmonella spp., Staphylococcus aureus Streptococci, Clostridium perfringes, and Escherichia coli. In addition, Lead (Pb), Cadmium (Cr), Chromium (Cr), Zinc (Zn), Iron (Fe), Copper (Cu) and Manganese (Mn) have been detected in green leafy vegetables over the years in most Ghanaian cities. Pesticides residues from organochlorine, organophosphorus and synthetic pyrethroid have also been reported. Overall, microbial, heavy metals and pesticide residue contamination of Ghanaian green leafy vegetables on the farms and markets were significant. Hence, mitigation measures to curb the contamination of these vegetables, through the food chain, is urgently required to safeguard public health.