Cadmium distribution in the testa or outer shell and cotyledon or nib of the cocoa bean

What is it about?

There are food safety concerns regarding heavy metal contamination in cocoa.The nib or cotyledon of the cocoa seed or bean is used to make cocoa products such as chocolate. The testa is discarded prior to processing although some fragments may be included inevitably. In order to determine the food safety of consignments of cocoa beans, analytical tests are done routinely. These most often involve the whole seed or bean (nib or cotyledon plus testa or shell/seed coat). It is critical to understand how the cocoa plants absorbs this heavy metal and whether the concentration varies from one organ or tissue to another in the plant. Since the cocoa nib is the product of trade, it is important to understand the level of cadmium that is distributed there and whether it is higher or lower than in the surrounding testa, which is discarded prior to processing. Preferential uptake of cadmium in the testae suggests that the levels of cadmium there would be higher than in the nibs. Therefore it is not valid or justifiable to measure the levels in this discarded tissue in routine food safety testing. This practice is detrimental to the cocoa producers.

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Why is it important?

The elucidation of the fact that the cocoa testae absorb more cadmium relative to the nibs or cotyledons has tremendous significance to the cocoa market. The manner in which cocoa bean food safety is currently assessed is not not favourable to cocoa producers. This empirical study indicates that cadmium levels must be measured in the nibs of cocoa beans (and not the discarded testae) to facilitate an equitable assessment of the food safety, in terms of cadmium contamination, of consignments of cocoa beans.

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