Heavy Metal Analysis in Cocoa Powder Using ICP-MS: Implications for Food Safety and Metrology in South Africa

Cocoa powder is a popular product for its unique flavour and health benefits. However, the presence of heavy metals and other trace elements, such as Cd, B, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Al, P, S, K, As, and Ca, has raised concerns regarding food safety and regulatory compliance. South Africa relies on imported cocoa powder, mainly sourced from cocoa-growing regions in West Africa and South America. Toxic elements like cadmium (Cd) and arsenic (As) are of particular concern due to their potential health risks, including kidney damage, neurotoxicity, and carcinogenicity.

On the contrary, essential elements like potassium (K) and iron (Fe) contribute to the nutritional value of cocoa products. Accurately quantifying these elements is important for ensuring compliance with international food safety standards, such as those set by the Codex Alimentarius Commission and the European Union (EU).

This study highlights the key role of metrology in ensuring the reliability, accuracy, and traceability of elemental analysis using inductively coupled plasma mass spectrometry (ICP-MS). The involvement of South Africa's National Metrology Institute (NMISA) ensures that measurements conducted by analytical laboratories are traceable to the International System of Units (SI), encouraging global comparability and confidence in the results.

Integrating ICP-MS with metrological principles provides a robust framework for monitoring the concentration levels of multi-elements in cocoa powder. This synergy ensures food safety, supports compliance with international standards, and enhances South Africa's ability to participate in global trade. By addressing both toxic and essential elements, this approach not only safeguards public health but also contributes to research and innovation in food quality and safety.

In this study, the concentration levels of Cd, B, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Al, P, S, K, As, and Ca in cocoa powder using ICP-MS were investigated. ICP-MS is a highly sensitive and versatile analytical technique, enabling the detection of elements at trace and ultra-trace levels, which is important for measuring toxic elements and essential nutrients in food products.

Microwave digestion was used to prepare the cocoa powder samples. Quality control samples and certified reference materials (CRMs) were also prepared with the cocoa samples to validate the measurement method to ensure the accuracy, precision, and reliability of the results.