Nonnutritive Constituents in Chocolate and Cocoa

Contaminants include the toxic metals lead, cadmium, and nickel; the pesticides; and ochratoxin A, a mold-produced toxin. Lead, ochratoxin A, and probably pesticides are associated with the shells and enter cocoa and chocolate through imperfect shell removal. Lead, though present in soil, is not taken up by the plant. What lead is found in cocoa and chocolate results from beans being dried on bare soil, which adheres to the shell or from which it is absorbed by the shell. Cadmium and nickel are taken up by the plant from the soil, and the concentration in the bean depends on soil type. Fertilizer use may increase the cadmium content of the soil. Ochratoxin A concentration in cocoa powder is greater than expected from simple inclusion of shell fragments, as if, like lead, it is concentrated during processing. Concentrations of contaminants are generally within mandated guidelines, and the fraction of chocolate products in the diet is so small that what contaminants are present will have little effect on overall intake.