Comparative analysis of detecting ochratoxin A in cocoa powder samples using high performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA)

Abstract

Different cocoa powder (CP) samples were analyzed for mycoflora contaminants as a means of ensuring food safety. A total of 360 samples of 24 brands of CP were purchased between April and November, 2007. Ten-fold serial dilutions of the cocoa samples in sabouraud dextrose broth (SDB) were plated on potato dextrose agar (PDA) for yeast and mould counts. Colonies of yeasts and moulds, isolated from the cocoa samples were identified by standard mycological methods. The Ochratoxin A (OTA) extraction and detection from the samples was determined by high performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA). The common fungi isolated were Aspergillus niger, Saccharomyces cerevisae, Penicillium chrysogenum while the least encountered fungi were Aspergillus melleus andAspergillus ochraceous in the tested cocoa powder samples. This study showed that CP, which forms the bulk ingredient of cocoa-based beverages, is a possible source of microbial contamination to the beverages, though the values obtain from the use of HPLC is below the recommended value of 5 µg/kg as specified by European Union (EU), thus making the cocoa powder produced from these areas safe for consumption. Key words: Cocoa powder, mycoflora, beverages, contaminants, food safety.