New examinations of mycotoxin carryover to cocoa beans

Abstract

Mycotoxins are secondary metabolites which can form on various foodstuffs through the growth of certain fungi. Ochratoxin A (OTA) and the aflatoxins B₁ B₂, G₁ and G₂ have been detected in low concentrations in cocoa and cocoa products. As regards the question of in what stages of the cocoa production process a contamination with the mycotoxin-producing moulds and the formation of mycotoxins takes place, it is assumed that in the case of cocoa the contamination is not concerning the individual beans but the fermentation units.

A model test was carried out to provide information on the process by which a possible carryover of the above-mentioned mycotoxins to cocoa beans occurs during the fermentation process. For this purpose fresh cocoa beans were left to soak in an artificial mycotoxin-containing fermentation solution. The mycotoxin levels in the cocoa beans were regularly determined over a period of 12 days. New findings were made as regards the migration of mycotoxins during the fermentation process. We interpret the divergent uptake behaviour of the mycotoxins to indicate that the transport of OTA and that of aflatoxins does not take place in the same manner. This is possibly caused by chemico-physical effects, such as the different polarities of the mycotoxins.