Identification of the Critical Points For Polycyclic Aromatic Hydrocarbon Contamination along the Cocoa Processing and Storage Chain in Ghana

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Cocoa, a natural resource has shouldered the socio-economic life of Ghana through generation of employment and foreign exchange since its introduction into the country in 1815 by the Dutch Missionaries. Nonetheless, the industry faces some challenges; Exported cocoa has come under strict scrutiny due to elevation of the levels of a carcinogenic, mutagenic and an endocrine-disrupting compound termed polycyclic aromatic hydrocarbon (PAH). Although the general post-harvest handling of cocoa has received some level of attention, how critical the contributions of the specific primary processing and storage stages along the chain are and the level of knowledge of farmers on the causes and effect of PAH contamination are not known. These situations shield areas that need intense focus and are assessed by this study to help in designing policies and strategies for quality improvement. The concentrations of PAH in cocoa sampled from Ashanti, Brong-Ahafo, Central, Eastern, Western-North, Western-South and Volta regions (cocoa-regions) of Ghana were analyzed using the Gas-Chromatography Mass Spectrometer. Also interview via questionnaires were used to ascertain knowledge of farmers and other handlers including purchasing officials with regards to PAH level. Results indicate that cocoa beans processing involves pods gathering and opening, bean fermentation and drying. It was followed by bagging and storage before shipment. PAH concentration was higher in the shell than the nib (although < EU‟s threshold limit of 2ppb) and occurred during drying (0.925 ppb), depot storage (1.486 ppb) and shipment (1.842 ppb). Inappropriate practices e. g drying near fire and vehicle roadside which promote contact of beans with smoke, petroleum products e. g. oil, diesel and petrol could account for this situation. Lack of knowledge by cocoa farmers due mainly to low level of education was also established as a critical factor that requires greater attention.
A Thesis Submitted to the Department of Materials Engineering, Kwame Nkrumah University of Science and Technology, in Partial Fulfillment of the Requirements for the award of Master of Science Degree in Environmental Resources Management