Title : Prevalence and High Incidence of Sterigmatocystin in cocoa beans from Three Agro- ecological zones (AEZs) of Nigeria
Abstract:
Composite samples of fermented and dried cocoa beans collected from three agro ecological zones (AEZs) of cocoa production in Nigeria were evaluated for the presence of Sterigmatocystin (STC) and some other multitoxins with the liquid chromatography Tandem Mass Spectroscopy (LC-MS/MS) technique. The possible effects of fermentation methods and Time, Methods of drying and drying time on the prevalence and incidence of STC were evaluated using the Liquid Chromatography Tandem Mass Spectroscopy (LC-MS/MS) methods. The study showed a very high prevalence of STC (100%) with values in the range of 0.02 and 1934µg/kg in all the cocoa samples analyzed. The methods and time of cocoa fermentation as well as the drying method and drying times have significant effects only on the STC incidence in all the positive samples. The highest incidence of STC was observed at the Derived Savannah and lowest at the Humid Forest zones. Out of the eighty multitoxins detected, seventy three of these have not been detected in Nigerian cocoa beans or any other cocoa producing countries of the world. The bacterial toxins had a low concentration and were not a source of concern. In conclusion, this study has established the prevalence of STC in cocoa beans from all the AEZs studied irrespective of the method and time of both the fermentation and drying. Therefore, to reduce the prevalence of STC, Post-harvest Practices of cocoa beans should be handled with Good Agricultural Practices (GAP). There is a need for an immediate action plan for mycotoxin Mitigation in Nigerian cocoa especially in the Derived Savannah zone in view of the economic importance of cocoa beans. Key words: STC, Cocoa, Fermentation, Drying, Prevalence, Incidence
