Mycoflora and nutritional components of cocoa powder samples in South West Nigeria

The production of cocoa powder (CP), the major ingredient of cocoa-based beverages, has been on the increasing trend in Nigeria without much concern for whether or not they meet the microbiological criteria for food safety. This study was, carried out to investigate the mycroflora and intrinsic factors of twenty four brands of cocoa powder samples bought from different sources in South-West Nigeria with a view to determining their food safety and how their intrinsic factors affect microbial growth. A total of 360 samples of 24 brands of CP were purchased between April and November, 2007. The viable bacteria and mould counts were determined using standard plate count while the microbial isolates were identified using cultural, microscopic and biochemical methods. The pH, proximate, mineral and physical parameters were determined using recommended standard methods by Association of Official Analytical Chemists (AOAC). Student t-test and multiple linear regressions were employed in the statistical analysis of the data. The result showed variation in percentage of fat, protein and carbohydrate content as well as pH values from one CP to another. The pH values ranged from 6.4 to 7.4 while the moisture content of the CP was between 0.80 and 1.86%. The CP samples were found to be rich in magnesium, iron, sodium, potassium and carotenoids but deficient in vitamins. The common fungi isolated were Aspergillus niger, Saccharomyces cerevisae, Penicillium chrysogenum while the least encountered fungi were Aspergillus melleus and Aspergillus chraceouso. The study showed that CP, which forms the bulk ingredient of cocoa-based beverages, is a possible source of microbial contaminant to the beverages. The result also showed that the CP samples examined were rich in minerals and nutrients which could account for the survival of fungi in the samples.