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■ West Africa excluding Côte d'Ivoire, N=348

H Asia & Oceania, N=136 I I Americas, N=213

■ West Africa excluding Côte d'Ivoire, N=348

H Asia & Oceania, N=136 I I Americas, N=213

Figure 3. Ochratoxin A levels in cocoa beans imported into Europe from different regions of the world.

Figure 3. Ochratoxin A levels in cocoa beans imported into Europe from different regions of the world.

OTA levels in cocoa beans

For six seasons, starting in 1999, the European industry has analyzed samples of imported cocoa beans from different origins. Statistical sampling plans were not used for the selection of which lots to analyze and not all producing countries were included. Therefore the results presented (Fig. 3) are indicative, rather than definitive. Ochratoxin A contaminated cocoa beans were found in all cocoa-producing regions. Higher toxin levels were more frequent in beans from Cote d'lvoire, but the number of analyzed samples from Cote d'lvoire is about three times larger than from any other region.

The standard method for evaluating the quality of cocoa beans is a cut test in which the interior of a certain number of beans that have been longitudinally cut are visually inspected (Wood and Lass, 1985). One of the parameters in the cut test is visibly moldy beans. Cut tests were made on a large number of cocoa bean samples, which also were analyzed for ochratoxin A. There was no significant correlation between the number of moldy beans identified in the cut test, or any other quality parameter, and ochratoxin A contamination. The molds scored in a cut check apparently are not the species responsible for ochratoxin A contamination.

Industrial conversion of beans to cocoa products

Cocoa beans are not eaten as such, but instead undergo an industrial conversion (Fig. 4) before consumption. During this industrial processing the aw is << 0.8, which is too low for ochratoxin A production. The first steps in processing are roasting and removal of the shell. During roasting the final bean temperature reaches 100-120°C and the duration is 15-70 min (Minifie, 1982). Boudra et al. (1995) showed that ochratoxin A is heat stable and that at most 20% of the toxin in wheat was decomposed by dry heat at 100°C for 160 min or 150°C for 32 min. Thus, the roasting of cocoa beans is not expected to significantly reduce the level of ochratoxin A present.

Figure 4. Steps in the industrial processing of cocoa beans. Processing studies were made at the roasting/deshelling and pressing stages.

The amount of ochratoxin A in the shell (discarded and not used for milling) and in the kernel (nib fraction; used for milling) of cocoa beans, was determined by analyzing samples of the two fractions (about 200 g shell and 1 kg nibs) taken simultaneously from industrial winnowers. Based on the measured concentrations and the assumption that the shell fraction represents 12% of the bean (Fincke, 1965), the ochratoxin A concentration in the whole beans (before removal of the shell fraction) was calculated. The calculated ochratoxin A concentration in the whole beans was between 0.3 and 3.0 ng/g. An average of 48% (range 25-72%) of the ochratoxin A in the beans is removed with the shell fraction.

The nibs are milled to form cocoa liquor, a viscous liquid containing ~ 50% fat. The cocoa liquor can be mixed with other ingredients to produce chocolate or it can be "pressed" to produce cocoa butter and cocoa powder. After pressing, all of the ochratoxin A originally in the nibs is recovered in the cocoa powder. Ochratoxin A has not been found in the cocoa butter fraction (and is not expected there), since ochratoxin A is not lipophilic. During other processing steps, e.g., milling, conching, and storage of cocoa liquor and chocolate, the temperature is less than that needed to decompose ochratoxin A, so no reductions in toxin levels are expected to occur during these steps. The cocoa liquor or cocoa powder is mixed with other ingredients to make consumer products and this "dilution" further reduces the ochratoxin A levels in the products consumed.

OTA levels in cocoa and chocolate products

Levels of ochratoxin A in samples of cocoa and chocolate products produced in Europe have been measured by industry for several years. The chocolate samples measured were solid milk or dark chocolate products without inclusions or fillings, i.e., there was no ochra-

Table 2. Ochratoxin A levels in chocolate and cocoa products.
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