intoxicating chocolate

Vincent

De Mesmaeker

Ruth

Vanderschueren

Na vele jaren van onderzoek en debat, voerde de Europese Comissie op 1 januari 2019 een nieuwe wet in die de cadmium (Cd) concentratie in chocoladeproducten beperkt. De aanwezigheid van dit zwaar metaal in chocolade kan grotendeels toegeschreven worden aan de de origine van de cacaobonen. Dit maakt dat de exportpositie van veel Zuid- Amerikaanse landen zwaar onder vuur komt te staan.

In het kader van deze nieuwe regulering trachtten we een mogelijke strategie te ontwikkelen om Cd in cacaobonen te verlagen. De focus van dit onderzoek lag op de natuurlijke fermentatie van cacaobonen. Deze na-oogst behandeling is immers cruciaal in de ontwikkeling van het o zo karakteristieke cacao-aroma waar we allen zo dol op zijn. Door de beperkte kennis omtrent Cd in cacao, werd eerst de spreiding van Cd in ongefermenteerde cacao onderzocht. Later werd dan ook de mate waarin Cd zich (mogelijks) herverdeeld tijdens de fermentatie onderzocht.

We concludeerden dat Cd zich voornamelijk opstapelt in de zaadhuid (testa) van de cacaoboon. De Cd concentratie in het binnenste deel, de cacao nib, was daarentegen tot wel 50 % lager. Tijdens fermentatie nam dit verschil in concentratie nog verder toe: er was dus met andere woorden een duidelijke uitwaartse migratie van Cd. Deze herverdeling is mogelijks toe te schrijven aan veranderingen in pH van de verschillende weefsels. Zo zagen we dat Cd meer werd gemobilizeerd indien de nib pH beneden een bepaalde waarde (rond pH 5) daalde. Deze afname in pH werd hoodzakelijk veroorzaakt door een inwaartse beweging van kleine organische zuren zoals azijnzuur en melkzuur. Uitgaande van deze observaties, zou een wasbehandeling met pH verlagende substanties dus mogelijks kunnen leiden tot een lagere nib Cd op het einde van de fermentatie. Aangezien enkel nibs worden gebruikt voor verdere verwerking, volgt hieruit dat de finale Cd concentratie in chocolade dus verlaagd zou kunnen worden door gebruik te maken van deze strategie.

Of we nu door deze regulering met z’n allen minder chocolade moeten gaan eten is nog maar de vraag. Zo mag een volwassen man van 70 kg bijvoorbeeld tot 1,75 kg melkchocolade of 220 g donkere chocolade per week eten alvorens hij nadelige effecten van de geassocieerde Cd inname zal ervaren. Wie toch verleidt wordt door de intoxische effecten van chocolade en dergelijke hoeveelheden wekelijks consumeert, zal zich dus eerder zorgen moeten maken om hart –en vaatziekten alvorens in te zitten met de toxiciteit van Cd.

cacao

Bibliografie

Abt, E., Sam, J.F., Gray, P., Robin, L.P. (2018). Cadmium and lead in cocoa powder and chocolate products in the US Market Cadmium and lead in cocoa powder and chocolate products in the US Market. Food Additives and Contaminants, 3210, 1–11.

Åkesson, A., Lundh, T., Vahter, M., Bjellerup, P., Lidfeldt, J., Nerbrand, M., et al. (2005). Tubular and glomerular kidney effects in Swedish women with low environmental cadmium exposure. Environmental Health Perspectives, 113(11), 1627–1631.

Alfaro, M.R., Montero, A., Ugarte, O.M., Williams, C., Maria, A., Accioly, et al. (2015). Background concentrations and reference values for heavy metals in soils of Cuba. Environ Monit Assess, 187, 4198–4208.

Antila, E., Mussalo-Rauhamaa, H., Kantola, M., Atroshi, F., Westermarck, T. (1996). Association of cadmium with human breast cancer. Science of the Total Environment, 186(3), 251–256.

Arao, T., Ae, N. (2003). Genotypic variations in cadmium levels of rice grain. Soil Science and Plant Nutrition, 49(4), 473–479.

Argüello, D., Chavez, E., Lauryssen, F., Vanderschueren, R., Smolders, E., Montalvo, D. (2019). Science of the Total Environment Soil properties and agronomic factors affecting cadmium concentrations in cacao beans: A nationwide survey in Ecuador. Science of the Total Environment, 649, 120–127.

Arora, M., Weuve, J., Schwartz, J., Wright, R.O. (2008). Association of evironmental cadmium exposure with pediatric dental caries. Environmental Health Perspectives, 116(6), 821–825.

Barraza, F., Schreck, E., Lévêque, T., Uzu, G., López, F., Ruales, J., et al. (2017). Cadmium bioaccumulation and gastric bioaccessibility in cacao: A field study in areas impacted by oil activities in Ecuador. Environmental Pollution, 229, 950–963.

Beckett, S.T. (2008). The science of chocolate. Rsc Paperbacks, 39(5), 1–170.

Bertoldi, D., Barbero, A., Camin, F., Caligiani, A., Larcher, R. (2016). Multielemental fingerprinting and geographic traceability of Theobroma cacao beans and cocoa products.Food Control, 65, 46–53.

Buchet, J., Lauwerys, R., Roels, H., Bernard, A., Bruaux, P., Claeys, F., et al. (1990). Renal effects of cadmium body burden of the general population. The Lancet, 336, 699–702.

Camu, N., De Winter, T., Verbrugghe, K., Cleenwerck, I., Vandamme, P., Takrama, J. S., et al. (2007). Dynamics and biodiversity of populations of lactic acid bacteria and acetic acid bacteria involved in spontaneous heap fermentation of cocoa beans in Ghana. Applied and Environmental Microbiology, 73(6), 1809–1824.

Chavez, E., He, Z. L., Stoffella, P.J., Mylavarapu, R.S., Li, Y.C., Moyano, B., et al. (2015). Concentration of cadmium in cacao beans and its relationship with soil cadmium in southern

Ecuador. Science of the Total Environment, 533, 205–214.

Codex Alimentarius (2001). Standard for cocoa (cacao) mass (cocoa/chocolate liquor) and cocoa

cake. International food standards. Codex Stan 141-1983, 1-3.

De Vuyst, L., Weckx, S. (2016). The cocoa bean fermentation process: from ecosystem analysis

to starter culture development. Journal of Applied Microbiology, 121(1), 5–17.

EFSA (2011). Statement on tolerable weekly intake for cadmium. The EFSA Journal, 9(2), 1–19.

EFSA (2012). Cadmium dietary exposure in the European population, Scientific Report of EFSA.The EFSA Journal, 10(1), 2551(1-37).

European Commision (2014). Commision Regulation (EU) No 488/2014 of 12 May 2014 amending Regulation (EC) No 1881/2006 as regards to maximum levels of cadmium in foodstuffs. Official Journal of the European Union, L138, 75–79.

European Union. (2007). Cadmium oxide and cadmium metal Part I - environment. European Union Risk Assessment Report, (72), 1-678.

Fangmin, C., Ningchun, Z., Haiming, X., Yi, L., Wenfang, Z., Zhiwei, Z., et al. (2006). Cadmium and lead contamination in japonica rice grains and its variation among the different locations in southeast China. Science of the Total Environment, 359(1–3), 156–166.

Gálvez, S.L., Loiseau, G., Paredes, J. L., Barel, M., Guiraud, J.P. (2007). Study on the microflora and biochemistry of cocoa fermentation in the Dominican Republic. International Journal of Food Microbiology, 114(1), 124–130.

Gramlich, A., Tandy, S., Gauggel, C., López, M., Perla, D., Gonzalez, V., et al. (2018). Soil cadmium uptake by cocoa in Honduras. Science of the Total Environment, 612, 370–378.

Hellström, L., Elinder, C.G., Dahlberg, B., Lundberg, M., Järup, L., Persson, B., et al. (2001). Cadmium exposure and end-stage renal disease. American Journal of Kidney Diseases, 38(5), 1001–1008.

Hogervorst, J., Plusquin, M., Vangronsveld, J., Nawrot, T., Cuypers, A., Van Hecke, E., et al. (2007). House dust as possible route of environmental exposure to cadmium and lead in the adult general population. Environmental Research, 103(1), 30–37.

IARC. (1993). Beryllium, Cadmium, mercury and exposures in the glass manufacturing industry.IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, 58, 1–417.

Il’yasova, D., Schwartz, G.G. (2005). Cadmium and renal cancer. Toxicology and Applied Pharmacology, 207(2), 179–186.

International Cocoa Organization. (2018). Production of cocoa beans. Quarterly Bulletin of Cocoa Statistics, XLIV(3).

Ishikawa, S., Ishimaru, Y., Igura, M., Kuramata, M., Abe, T., Senoura, T., et al. (2012). Correction for Ishikawa et al., Ion-beam irradiation, gene identification, and marker-assisted breeding in the development of low-cadmium rice. Proceedings of the National Academy of Sciences,109(47), 19166–19171.

Järup, L., Åkesson, A. (2009). Current status of cadmium as an environmental health problem.Toxicology and Applied Pharmacology, 238(3), 201–208.

Järup, L., Berglund, M., Elinder, C., Nordberg, G., Vanter, M. (1998). Health effects of cadmium exposure: a review of the literature and a risk estimate. Scandinavian Journal of Work, Environment & Health, 24(1), 1–51.

Järup, L., Elinder, C. G., Hellström, L., Alfvén, T., Carlsson, M. D., Grubb, A., et al. (2000). Low level exposure to cadmium and early kidney damage: The OSCAR study. Occupational and Environmental Medicine, 57(10), 668–672.

Jones, S.R., Atkin, P., Holroyd, C., Lutman, E., Vives i Batlle, J., Wakeford, R., et al. (2007). Lung cancer mortality at a UK tin smelter. Occupational Medicine, 57(4), 238–245.

Kubo, K., Watanabe, Y., Oyanagi, A., Kaneko, S., Chono, M., Matsunaka, H., et al. (2008). Cadmium Concentration in Grains of Japanese Wheat Cultivars: Genotypic Difference and Relationship with Agronomic Characteristics. Plant Production Science, 11(2), 243–249.

Lado, L.R., Hengl, T., Reuter, H. I. (2008). Geoderma Heavy metals in European soils: A geostatistical analysis of the FOREGS Geochemical database. Geoderma, 148(2), 189–199.

Lee, C.K., Low, K. S. (1985). Determination of Cadmium, Lead, Copper and Arsenic in Raw Cocoa, Semifinished and Finished Chocolate Products. Pertanika, 8(2), 243–248.

Lefeber, T., Papalexandratou, Z., Gobert, W., Camu, N., De Vuyst, L. (2012). On-farm implementation of a starter culture for improved cocoa bean fermentation and its influence on the flavour of chocolates produced thereof. Food Microbiology, 30(2), 379–392.

Lewis, C., Lennon, A.M., Eudoxie, G., Umaharan, P. (2018). Genetic variation in bioaccumulation and partitioning of cadmium in Theobroma cacao L . Science of the Total Environment, 640–641, 696–703.

MacIntosh, D.L., Spengler, J.D., Özkaynak, H., Tsai, L.H., Barry Ryan, P. (1996). Dietary exposures to selected metals and pesticides. Environmental Health Perspectives, 104(2), 202–209.

Matsuda, K., Kobayashi, E., Okubo, Y., Suwazono, Y., Kido, T., Nishijo, M., Nakagawa, H., Nogawa, K. (2003). Total Cadmium Intake and Mortality among Residents in the Jinzu River Basin, Japan. Archives of Environmental Health, 58(4), 218–222.

Mcdowell, R.W., Taylor, M.D., Stevenson, B.A. (2013). Agriculture , Ecosystems and Environment Natural background and anthropogenic contributions of cadmium to New Zealand soils. Agriculture, Ecosystems and Environment, 165, 80–87.

vii

McElroy, J.A., Shafer, M.M., Trentham-Dietz, A., Hampton, J.M., Newcomb, P.A. (2006). Cadmium exposure and breast cancer risk. Journal of the National Cancer Institute, 98(12), 869–873.

McElroy, J.A., Shafer, M.M., Trentham-Dietz, A., Hampton, J.M., Newcomb, P.A. (2007). Urinary cadmium levels and tobacco smoke exposure in women age 20-69 years in the United States. Journal of Toxicology and Environmental Health - Part A: Current Issues, 70(20), 1779–1782.

Mounicou, S., Szpunar, J., Lobinski, R., Andrey, D., Blake, C. (2002a). 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). J. Anal. At. Spectrom., 17, 880–886.

Mounicou, S., Szpunar, J., Lobinski, R., Andrey, D., Blake, C. (2002b). Development of a sequential enzymolysis approach for the evaluation of the bioaccessibility of Cd and Pb from cocoa. Analyst, 127, 1638–1641.

Mounicou, S., Szpunar, J., Lobinski, R., Andrey, D., Blake, C. (2003). Concentrations and bioavailability of cadmium and lead in cocoa powder and related products. Food Additives and Contaminants, 20(4), 343–352.

Nielsen, D.S., Teniola, O.D., Ban-Koffi, L., Owusu, M., Andersson, T.S., Holzapfel, W. H. (2007). The microbiology of Ghanaian cocoa fermentations analysed using culture-dependent and culture-independent methods. International Journal of Food Microbiology, 114, 168–186.

Nriagu, J.O. (1989). A global assessment of natural sources of atmospheric trace metals. Nature,338, 47–49.

Nriagu, J.O. (1990). Global Metal Pollutions: Poisoning the Biosphere? Environment, 32(7), 1– 6.

Nriagu, J.O. (1996). A history of global metal pollution. Science, 272(5259), 1–4.

Nriagu, J.O., & Pacyna, J. (1988). Quantitative assesment of worldwide contamination of air, water

and soils by trace metals. Nature, 333(12), 134–139.

Olsson, I.M., Bensryd, I., Lundh, T., Ottosson, H., Skerfving, S., Oskarsson, A. (2002). Cadmium in Blood and Urine--Impact of Sex, Age, Dietary Intake, Iron Status, and Former Smoking-- Association of Renal Effects. Environmental Health Perspectives, 110(12), 1185–1190.

Pacyna, J., Pacyna, E.G. (2001). An assessment of global and regional emissions of trace metals to the atmosphere from anthropogenic sources worldwide. Environmental Reviews, 9(4), 269–298.

Papalexandratou, Z., De Vuyst, L. (2011). Assessment of the yeast species composition of cocoa bean fermentations in different cocoa-producing regions using denaturing gradient gel

viii

electrophoresis. FEMS Yeast Research, 11(7), 564–574.

Papalexandratou, Z., Vrancken, G., de Bruyne, K., Vandamme, P., De Vuyst, L. (2011). Spontaneous organic cocoa bean box fermentations in Brazil are characterized by a restricted species diversity of lactic acid bacteria and acetic acid bacteria. Food Microbiology, 28(7), 1326–1338.

Pereira, G.V. de M., Miguel, M.G. da C.P., Ramos, Cí.L., Schwan, R.F. (2012). Microbiological and physicochemical characterization of small-scale cocoa fermentations and screening of yeast and bacterial strains to develop a defined starter culture. Applied and Environmental Microbiology, 78(15), 5395–5405.

Ramtahal, G., Chang Yen, I., Ahmad, N., Bekele, I., Bekele, F., Maharaj, K., et al. (2015). Prediction of Soil Cadmium Bioavailability to Cacao (Theobroma cacao L.) using Single- Step Extraction Procedures. Communications in Soil Science and Plant Analysis, 46(20), 2585–2594.

Ramtahal, G., Chang Yen, I., Bekele, I., Bekele, F., Wilson, L., Maharaj, K., et al. (2015). Implications of distribution of cadmium between the nibs and testae of cocoa beans on its marketability and food safety assessment. Quality Assurance and Safety of Crops and Foods,7(5), 731–736.

Ramtahal, G., Yen, I.C., Bekele, I., Bekele, F., Wilson, L., Maharaj, K., et al. (2016). Relationships between Cadmium in Tissues of Cacao Trees and Soils in Plantations of Trinidad and Tobago.Food and Nutrition Sciences, 07(01), 37–43.

Roberts, T. L. (2014). Cadmium and phosphorous fertilizers: The issues and the science. Procedia Engineering, 83, 52–59.

Romanens, E., Näf, R., Lobmaier, T., Pedan, V., Leischtfeld, S.F., Meile, L., et al. (2018). A lab- scale model system for cocoa bean fermentation. Applied Microbiology and Biotechnology,102(7), 3349–3362.

Schwan, R.F. (1998). Cocoa fermentations conducted with a defined microbial cocktail inoculum.Applied and Environmental Microbiology, 64(4), 1477–1483.

Schwan, R.F., Fleet, G.H. (2012). Cocoa and Coffee Fermentations. CRC Press: Taylor & Francis Group.

Schwan, R. F., Wheals, A. E. (2004). The microbiology of cocoa fermentation and its role in chocolate quality. Critical Reviews in Food Science and Nutrition, 44(4), 205–221.

Sigel, A., Sigel, H., Sigel, R.K.O. (2013). Cadmium: From Toxicity to Essentiality. Metal Ions in Life Sciences (Vol. 11).

Smolders, E., Mertens, J. (2013). Chapter 10: Cadmium. Heavy Metals in Soils: Trace Metals and Metalloids in Soils and Their Bioavailabolity, 22, 283–311.

Thyssen, G.M., Keil, C., Wolff, M., Sperling, M., Kadow, D., Haase, H., et al. (2018). Bioimaging

of the elemental distribution in cocoa beans by means of LA-ICP-TQMS. Journal of Analytical Atomic Spectrometry, 33(2), 187–194.

Tolcin, A.C. (2018). U.S. Geological Survey, (703), 40-41.

Vahter, M., Berglund, M., Slorach, S., Friberg, L., Sarić, M., Zheng, X., et al. (1991). Methods for integrated exposure monitoring of lead and cadmium. Environmental Research, 56(1), 78– 89.

Valiente, C., Molla, E., Martin-cabrejas, M.M., Lopez-andreu, F.J., Esteban, R.M. (1996). Cadmium binding capacity of cocoa and isolated total dietary fibre under physiological pH conditions. Journal of Science and Food Agriculture, 72, 476–482.

Vogel-Mikus, K., Pongrac, P., Kump, P., Ne, M., Vogel-mikus, K., Povh, B., et al. (2007). Localisation and quantification of elements within seeds of Cd / Zn hyperaccumulator Thlaspi praecox by micro-PIXE. Environmental Pollution, 147, 50–59.

Wood, G.A.R., Lass, R.A. (1985). Cocoa. Oxford: Blackwell Science.

Yanus, R.L., Sela, H., Borojovich, E.J.C., Zakon, Y., Saphier, M., Nikolski, A., et al. (2014). Trace

elements in cocoa solids and chocolate: An ICPMS study. Talanta, 119, 1–4.

Zarcinas, B.A., Ishak, C.F., Mclaughlin, M.J., Cozens, G. (2004a). Heavy metals in soils and crops in southeast Asia: Peninsular Malaysia. Environmental Geochemistry and Health, 26, 343– 357.

Zarcinas, B.A., Pongsakul, P., Mclaughlin, M.J., Cozens, G. (2004b). Heavy metals in soils and crops in southeast Asia . 2 . Thailand. Environmental Geochemistry and Health, 26, 359–371.

Zhai, Q., Guo, Y., Tang, X., Tian, F., Zhao, J., Zhang, H., et al. (2019). Removal of cadmium from rice by Lactobacillus plantarum fermentation. Food Control, 96 (1800), 357–364.

Zhang, X., Chen, D., Zhong, T. (2015). Assessment of cadmium ( Cd ) concentration in arable soil in China. Environmental Science Pollution Result, 22, 4932–4941.