Cocoa beans are susceptible to fungal contamination during many of these processing steps. Microbial growth is affected by intrinsic parameters of cocoa beans such as pH, by water activity and by the various organic acids produced during fermentation. Besides causing deteriorative alteration of sensorial properties, the presence of filamentous fungi in cocoa and chocolate is also a cause for concern due to the possibility of mycotoxin formation. Both aflatoxin and ochratoxin A have been reported from cocoa and chocolate.
The discovery of ochratoxin A in cocoa and by-products prompted international discussions. In 2012 the Codex Committee on Contaminants in Food elaborated a discussion paper on ochratoxin A in cocoa (Codex Alimentarius Commission, 2012). Information was gathered on the occurrence of ochratoxin A in cocoa and by-products to determine levels of contamination, the contribution of these products to ochratoxin A in the human diet, to elucidate the main factors responsible for ochratoxin A synthesis in cocoa and to reduce it during processing. A code of practice was formulated and is under discussion (Codex Alimentarius Commission, 2013).
This review focuses on the factors affecting the development of filamentous fungi and the potential for formation of aflatoxins and ochratoxin A at all processing stages. An update on international reports of mycotoxins in cocoa and chocolate is also provided.