Implications of distribution of cadmium between the nibs and testae of cocoa beans on its marketability and food safety assessment

Main Article Content

G. Ramtahal
I. Chang Yen
I. Bekele
L. Wilson
K. Maharaj
B. Sukha


cadmium, cocoa beans, cocoa products, food safety, nibs, testae, shells


There is increasing concern globally, regarding the consumption of foods contaminated with heavy metals such as cadmium (Cd), with consequent implementation of stringent food safety standards for consumer protection. Cd contents of cocoa beans can affect whether shipments of beans can be sold and whether cocoa products manufactured from beans with Cd can meet food safety standards. Cd determinations in bean exports are usually carried out on whole beans, which are comprised of nibs and the covering testae/shells, the latter being impossible to completely remove from the nibs used in chocolate and cocoa powder manufacture. The aim of this study was to evaluate the distribution of Cd levels between the nibs and shells of cocoa beans. This can allow for assessment of possible implications of the analytical protocols used for Cd determination in cocoa beans and the possible consequences for the safety of cocoa products made from such beans. Fermented and dried cocoa bean samples from different cacao-growing areas in Trinidad and Tobago were separated into nibs and shells and analysed for Cd by flame atomic absorption spectrometry, following exhaustive acid digestion. Shells of fermented and dried beans were found to contain significantly higher (P<0.05) and on average between 1 to 3 times as much Cd than the cocoa nibs. Analysis of whole cocoa beans, as well as incorporating shells in chocolates can thus result in Cd levels being significantly higher than using nibs only. These finding imply that the analysis of whole beans currently employed to determine their Cd contents, can affect the marketability and prices of cocoa beans. Questions also arise on whether the allowed incorporation of shells in the manufacture of cocoa products can affect their safety for human consumption.

Abstract 79 | PDF Downloads 84


Adams, M.L., Zhao, F.J., McGrath, S.P., Nicholson, F.A. and Chambers, B.J., 2004. Predicting cadmium concentrations in wheat and barley grain using soil properties. Journal of Environmental Quality33: 532-541.
Agency for Toxic Substances and Disease Registry (ATSDR), 1993. Toxicological profile for cadmium. U.S. Department of Health and Human Services, Public Health Service, Atlanta, GA, USA. Available at:
Agency for Toxic Substances and Disease Registry (ATSDR), 2004. Toxicological profile for copper. U.S. Department of Public Health and Human Services for Public Health Service, Atlanta, GA, USA. Available at:
Anderson, H., 2002. Law suit filed over toxic metals in chocolate. United Press International, Inc., Washington, DC, USA. Available at:
Beccaloni, E., Vanni, F., Beccaloni, M. and Carere, M., 2013. Concentrations of arsenic, cadmium, lead and zinc in homegrown vegetables and fruits: estimated intake by population in an industrialized area of Sardinia, Italy. Microchemical Journal 107: 190-195.
Burnfred, F., 2009. Food Safety in chocolate manufacture and processing. In: Beckett, S.T. (ed.) Industrial chocolate manufacture and use (4th Ed.). John Wiley & Sons Ltd, Chichester, UK, 530-549 pp.
Chaudri, A.M., Allaina, C.M.G., Badawya, S.H., Adamsa, M.L., McGratha, S.P. and Chambersc, B.J., 2001. Cadmium content of wheat grain from a long-term field experiment with sewage sludge. Journal of Environmental Quality 30: 1575-1580.
Codex Alimentarius Commission, 2001. Codex standard for cocoa (cacao) mass (cocoa/chocolate liquor) and cocoa cake. Codex Stan 141-1983, revised 1-2001. FAO, Rome, Italy.
Dahiya, S., Karpe, R., Hegde, A.G. and Sharma, R.M., 2005. Lead, cadmium and nickel in chocolates and candies from suburban areas of Mumbai, India. Journal of Food Composition and Analysis 18: 517-522.
Dickson, H., 2010. The analysis of cadmium in chocolate by graphite furnace atomic absorption spectrometry. Application note 43034. Thermo Fisher Scientific, Cambridge, UK.
Ducos, S., Hamester, M. and Godula, M., 2010. ICP-MS for detecting heavy metals in foodstuffs: the technology can analyze 50 samples in an hour. Food Quality & Safety magazine, Hoboken, NJ, USA. Available at:
European Commission (EC), 2000. Directive 2000/36/EC of the European parliament and of the council of 23 June 2000 relating to cocoa and chocolate products intended for human consumption. Official Journal of the European Communities L197: 19-25.
European Food Safety Authority (EFSA), 2011. Metal as contaminants in food. EFSA, Parma, Italy. Available at:
Fauziah, C.I., Zaharah, A.R., Zauyah, S. and Anuar, A.R., 2001. Proposed soil heavy metal reference values to be used for site assessment. Proceedings of Brownfield 2001: First National Conference on Contaminated Land. The Institution of Engineers, Petaling Jaya, Malaysia, pp. 1-20.
Food Standards Agency (FSA), 2008. Chemical contaminants interested parties letter: environmental contaminants (inorganic contaminants). FSA, London, UK. Available at:
Fowler, M.S., 1999. Cocoa beans: from tree to factory. In: Beckett, S.T. (ed.) Industrial chocolate manufacture and use. Blackwell Science, Oxford, UK, pp. 8-35.
Harrison, N., 2001. Inorganic contaminants in food: metals and metalloids. In: Watson, D. (ed.) Food chemical safety: contaminants (Volume 1). CRC Press, Boca Raton, FL, USA, pp. 148-168.
International Cocoa Organization (ICCO), 2006. Annual report 2006/2007. ICCO, Commonwealth House, London, UK.
International Cocoa Organization (ICCO), 2012. Ongoing review of legislation on cadmium in food in the EU: background and current state of play Available at:
International Union of Pure and Applied Chemistry (IUPAC), 1997. Compendium of chemical terminology. The gold book (2nd Ed.). Blackwell Scientific Publications, Oxford, UK. Available at:
Jalbani, N., Kazi, T.G., Afridi, H.I. and Arain, M.B., 2009. Determination of toxic metals in different brands of chocolates and candies, marketed in Pakistan. Pakistan Journal of Analytical Environmental Chemistry 10: 48-52.
Lee, C.K. and Low K.S., 1985. Determination of cadmium, lead, copper and arsenic in cocoa, semi-finished and finished chocolate products. Pertanika Journal 8: 243-248.
Minifie, B., 1999. Chocolate, cocoa, and confectionary: science and technology. Aspen Publishing, Gaithersburg, MD, USA, pp. 23-24.
Minitab, 2010. Minitab 16 statistical software. Stat guide. Minitab, Inc., Conventry, Uk.
Mounicou, S., Szpunar, J., Andrey, D., Blake, C. and Lobinski, R., 2003. Concentrations and bioavailability of cadmium and lead in cocoa powder and related products. Journal of Food Additives and Contaminants 20: 343-352.
Mounicou, S., Szpunar, J., Lobinski, R., Andrey, D. and Blake, C.J., 2002. Bioavailability of cadmium and lead in cocoa: comparison of extraction procedures prior to size-exclusion fast-flow liquid chromatography with inductively coupled plasma mass spectrometric detection (SEC-ICP-MS). Journal of Analytical Atomic Spectrometry 17: 880-886.
Nabulo, G., Black, C.R. and Young, S.D., 2011. Trace metal uptake by tropical vegetables grown on soil amended with urban sewage sludge. Environmental Pollution 159: 368-376.
Nogawa, K., Yamada,Y., Honda, R., Ishizaki, M., Tsuritani, I., Kawano, S. and Kato, K., 1983. The relationship between itai-itai disease among inhabitants of the Jinzu River basin and cadmium in rice. Toxicology Letters 17: 263-266.
Olmedo, P., Pla, A., Hernández, A.F., Barbier, F., Ayouni, L. and Gil, F., 2013. Determination of toxic elements (mercury, cadmium, lead, tin and arsenic) in fish and shellfish samples: risk assessment for the consumers. Environmental International 59: 63-72.
Reilly, C., 2002. Transition metals: chromium, manganese, iron, cobalt, nickel, copper and molybdenum In: Reilly, C. (ed.) metal contamination of food: its significance for food quality and human health (3rd Ed.). Blackwell Publishing, Chichester, UK, pp. 137-178.
Scott, C.A., Zarazúa, J.A. and Levine, G., 2000. Urban-wastewater reuse for crop production in the water-short Guanajuato River Basin, Mexico, Colombo, Sri Lanka. Research report 41. International Water Management Institute (IWMI), Colombo, Sri Lanka.
Singh, V.P, 2005. Toxic metals and environmental issues. Sarup & Sons, New Delhi, India, 362 pp.
United States Environmental Protection Agency (USEPA), 2003. National air quality and emissions trends report: special studies edition. Office of Air Quality Planning and Standards Emissions Monitoring and Analysis Division Air Quality Trends Analysis Group Research, Triangle Park, NC, USA.
Wieczorek, J., Wieczorek, Z. and Bieniaszewski, T., 2005. Cadmium and lead content in cereal grains and soil from cropland adjacent to roadways. Polish Journal of Environmental Studies 14: 535-540.
Wood, G.A.R., 2008. Establishment. In: Wood, G.A.R. and Lass, R.A. (eds.) Cocoa. John Wiley & Sons Ltd, Chichester, UK, 119-165 pp.