1.1. Mouldy off-flavours

These arise from the presence of moulds primarily inside the beans, and samples with as little as 3% of internally mouldy beans can impart a mouldy/earthy flavour to cocoa mass, henceforth to chocolate. This type of off-flavour cannot be removed during processing by the manufacturer. 

The main causes of the flavour defect are prolonged fermentation, inadequate or too slow drying (for example, due to poor weather conditions) and adsorption of moisture during transport or storage under adverse conditions. 

The presence of mouldy beans is revealed by the cut test. Note that there are legal limits for mouldy beans set by US FDA and authorities in other countries, as well as levels established in ISO 2451. These are used in CMAA and FCC contracts (see Quality Standards In the Cocoa Trade).

Mould growth also results in increased levels of free fatty acids (FFA) in cocoa butter (see 4. Cocoa Butter Characteristics) and specific moulds could even lead to the formation of mycotoxins (see 2.9 Mycotoxins, including Ochratoxin A (OTA)).