Impact of industrial treatments on ochratoxin A content in artificially contaminated cocoa beans

Abstract

Ochratoxin A (OTA) is a mycotoxin mainly produced by mould species of the genera Aspergillus and Penicillium, which grow on a variety of agricultural products. OTA-contaminated foodstuffs pose a major health hazard to consumers, including human and animal. In Côte d’Ivoire, numerous studies are being carried out to find the best way of preventing OTA contamination of cocoa raw material. The objectives of this investigation were to assess the impact of industrial treatment on OTA content in cocoa-derived products. Samples of cocoa pods were prepared under specific conditions promoting fungal proliferation on cocoa beans before processing. The beans underwent the usual industrial treatments – roasting, shelling, crushing, pressing and additive addition – and samples were taken at each stage. OTA was extracted with a methanol/3% sodium hydrogen carbonate solution and purified using an immunoaffinity column prior to HPLC analysis with fluorescence detection. OTA was detected in artificially contaminated cocoa beans at levels ranging from 3.4 to 44.7 µg kg⁻¹ with a mean value of 22.9 ± 3.6 µg kg⁻¹. OTA was mainly concentrated in the shell (93%). Roasting, shelling and additive addition significantly decreased levels of OTA by 24–40, 76 and 52%, respectively, with an overall reduction of ∼91%. These results indicate that industrial processing of cocoa has a real impact on the reduction of OTA in final cocoa products.

Keywords:

• ochratoxin A
• cocoa
• industrial processing
• HPLC
• Côte d’Ivoire

Acknowledgements

This study was conducted within the framework of the program “Strategy for the prevention of ochratoxin A (OTA) contamination of coffee and cocoa in Côte d’Ivoire”. The program was financially supported by the European Union (COM STABEX 99/1: DP OTA No. DP/IVC/2005/16), the organizations of coffee–cocoa network, including ARCC (Autorité de Régulation du Café Cacao), FRC (Fonds de Régulation et de Contrôle and BCC (Bourse du Café et Cacao). We thank the Ministry of Agriculture of Côte d’Ivoire for technical assistance.