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

DOI:10.3920/QAS2013.0388
Authors:
Gideon Ramtahal at University of the West Indies, St. Augustine
Gideon Ramtahal
I. Chang Yen
I. Chang Yen
I. Chang Yen
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I. Bekele at University of the West Indies, St. Augustine
I. Bekele
F. Bekele
F. Bekele
F. Bekele
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Abstract

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.
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Quality Assurance and Safety of Crops & Foods, 2015; ## (##): 1-6 WageningenAcademic
Publishers
ISSN 1757-837X online, DOI 10.3920/QAS2013.0388 1
1. Introduction
Cadmium (Cd), a non-essential and toxic metal, can
contaminate foods naturally through uptake from soils. Soils
may contain Cd naturally from volcanic activity (Burnfred,
2009), or through human activities, including farming (Scott
et al., 2000), manufacture/processing (Burnfred, 2009;
Dahiya et al., 2005; Minifie, 1999) or in automobile exhaust
emissions (ATSDR, 2004; USEPA, 2003). With agricultural
produce being a major source of Cd in foods (Chaudri et
al., 2001), its intake by humans is generally unavoidable
and may present significant health risks if consumed in
highly contaminated foods such as rice (Nogawa et al.,
1983; Reilly, 2002; Singh, 2005) and other cereals (Adams
et al., 2004; Wieczorek et al., 2005), vegetable (Beccaloni
et al., 2013; Nabulo et al., 2011) and shellfish (Olmedo et
al., 2013). Consumption of highly Cd-contaminated foods
can cause abdominal cramps, headaches, vomiting and
diarrhoea (ATSDR, 1993). While only 5-10% of ingested
Cd may be absorbed by the body, it may accumulate in
some tissues over time, with renal damage being caused
by long-term exposure (Harrison, 2001).
Recent research in food safety has raised concerns and actions
over the levels of Cd in chocolates and other cocoa-based
products. For example, the American Environmental Safety
Institute took legal action against chocolate manufacturers
for excessive levels of Cd in chocolates (Anderson, 2002).
Implications of distribution of cadmium between the nibs and testae of cocoa beans
on its marketability and food safety assessment
G. Ramtahal1*, I. Chang Yen1, I. Bekele2, F. Bekele3, L. Wilson2, K. Maharaj4 and B. Sukha4
1The University of the West Indies, Department of Chemistry, St. Augustine, Trinidad and Tobago; 2The University of the
West Indies, Department of Food Production, St. Augustine, Trinidad and Tobago;
3
The University of the West Indies, Cocoa
Research Unit, St. Augustine, Trinidad and Tobago; 4Ministry of Food Production, Trinidad and Tobago; gtahal@hotmail.com
Received: 28 December 2013 / Accepted: 4 January 2015
© 2015 Wageningen Academic Publishers
RESEARCH ARTICLE
Abstract
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.
Keywords: cadmium, cocoa beans, cocoa products, food safety, nibs, testae, shells
Quality Assurance and Safety of Crops & Foods, 2015 online ARTICLE IN PRESS
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