The California Office of Environmental Health and Human Hazard Administration (OEHHA) has listed cadmium and lead as chemicals known to cause birth defects or other reproductive harm.
Chocolate and confectionary products are among those which are a source of these minerals.
Cadmium and lead may contaminate the chocolate product at many points through the “bean to bar” process; these sources may depend on the cacao growing, fermenting, processing, manufacturing, shipping, and packaging practices.
One significant source is manmade pollution created by industrial processes as described above. Due to the persistence of these heavy metals in soil, they remain present even after the industrial source has been removed. Another source of these heavy metals in chocolate is through direct application of pesticides (lead and cadmium), phosphate fertilizers (cadmium), as well as sewage sludge disposal (lead and cadmium).
A third source of lead and cadmium is contamination through one of the various processing steps a bean undergoes after the harvest. These steps include fermentation, drying of the cacao bean, and manufacturing processes such as grinding, refining, and conching. Other opportunities for contamination are shipping, handling, and finally, packaging. Studies have shown that much of the “lead contamination in (chocolate) products occurs after the beans are harvested and dried, during the shipping of those beans and/or the manufacturing of cocoa and chocolate products.”
How can manufacturers prevent lead and cadmium contamination in their products?
Due to the variances in cocoa production chocolate manufacturers should test every batch of cocoa by an accredited laboratory received from their supply for lead and cadmium before production to ensure it is below or meets the minimum requirements of Proposition 65.
There may not be a single remedy to remove lead and cadmium in chocolate products. Chocolate manufacturers must understand the manufacturing practices and possible manmade sources of contamination and then take steps to identify the source(s) of the contamination. For example, the equipment used to process chocolate could be a primary source of lead or cadmium. Similarly, water used in processing, or shipping containers, may be high in lead. Once the source(s) are identified, suppliers and manufacturers can improve their practices; increase supply chain transparency; and effectively remove lead and cadmium from their final product.