Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was reviewed?
This perspective review focuses on the occurrence, origins, and factors influencing cadmium (Cd) and lead (Pb) contamination in cocoa and chocolate. It synthesizes research on how these metals enter the cocoa supply chain, concentrating on natural and anthropogenic sources, geographic differences, effects of cocoa content, and partitioning during production. The review also examines international regulatory efforts, such as those by Codex Alimentarius and the European Commission, to mitigate heavy metal contamination, and highlights ongoing research into agronomic, genetic, and processing-based mitigation strategies. Special attention is given to the elevated cadmium levels documented in cocoa from certain Latin American regions, their implications for trade, and the need for successful, scalable mitigation approaches.
Who was reviewed?
The review draws upon a wide body of published studies, governmental reports, and international regulatory documents relating to cadmium and lead in cocoa and chocolate. The reviewed literature includes studies analyzing cocoa products sourced from Africa, Latin America (especially Brazil, Ecuador, and Peru), and Asia, as well as regulatory and advisory outputs from bodies such as the FDA, FAO/WHO Joint Expert Committee on Food Additives (JECFA), Codex Committee on Contaminants in Foods (CCCF), and the European Commission. These sources encompass research on raw cocoa beans, cocoa nibs, cocoa powder, finished chocolate products, as well as interventions at various stages in the production process and supply chain.
Most important findings
| Critical Points | Details |
|---|---|
| Geographic Patterns of Contamination | Cadmium levels are significantly higher in cocoa and chocolate products sourced from certain Latin American regions compared to Africa and Asia. For example, mean Cd in Latin American cocoa powder can exceed 1300 µg/kg, while African products are consistently lower. Brazil is an exception, with lower Cd than other Latin American countries. Lead contamination does not follow the same geographic trend and is more related to processing and postharvest contamination. |
| Influence of Cocoa Content | Both Cd and Pb levels increase with higher cocoa content, especially in dark chocolate and cocoa powders. Correlations with percent cocoa are strong (R² for Cd up to 0.907). Cd partitions mainly into non-fat cocoa solids, while Pb is found in both fat and non-fat fractions. |
| Sources and Pathways | Cd contamination primarily originates from soil (geogenic sources, phosphate fertilizers, mining residues), with uptake modulated by soil pH, zinc content, salinity, and organic amendments. Pb contamination more often arises from environmental deposition and manufacturing processes, including exposure to Pb-containing dust, equipment, and storage containers. |
| Mitigation Strategies | Soil amendments (lime, biochar) can reduce Cd uptake by increasing soil pH or binding Cd, but effectiveness varies by field conditions. Agroforestry (shade trees), reduced fertilizer use, and use of low-Cd-accumulating cocoa genotypes show promise. Blending beans from different regions can reduce Cd in final products but is not suitable for single-origin fine chocolates. For Pb, adherence to good agricultural and manufacturing practices (as outlined in Codex COP) is critical. |
| International Regulation and Trade | The European Commission has set maximum Cd levels for chocolate and cocoa products, threatening market access for high-Cd Latin American products. Codex Alimentarius is developing harmonized maximum levels and codes of practice; the U.S. FDA has issued guidance on Pb. Industry and governmental research efforts are ongoing to develop practical mitigation measures. |
| Exposure Assessment | FDA and JECFA analyses conclude that, for most consumers, cocoa and chocolate are not major dietary sources of Cd or Pb relative to total intake, but children and high consumers in certain regions may approach or exceed provisional tolerable intake levels, especially for Cd. |
Key implications
For heavy metal certification, the review underscores the critical need to consider both geographic origin and cocoa content when assessing Cd and Pb risk. Certification programs must incorporate soil management, supply chain blending, and best manufacturing practices, aligning with evolving international standards to ensure compliance and minimize health risks.
Citation
Abt, E., & Posnick Robin, L. (2020). Perspective on Cadmium and Lead in Cocoa and Chocolate. Journal of Agricultural and Food Chemistry. https://dx.doi.org/10.1021/acs.jafc.9b08295
Cadmium is a persistent heavy metal that accumulates in kidneys and bones. Dietary sources include cereals, cocoa, shellfish and vegetables, while smokers and industrial workers receive higher exposures. Studies link cadmium to kidney dysfunction, bone fractures and cancer.
Lead is a neurotoxic heavy metal with no safe exposure level. It contaminates food, consumer goods and drinking water, causing cognitive deficits, birth defects and cardiovascular disease. HMTC’s rigorous lead testing applies ALARA principles to protect infants and consumers and to prepare brands for tightening regulations.
