Surveillance of Ochratoxin A in cocoa beans from cocoa-growing regions of Ghana

Objectives: Cocoa is one of the agricultural commodities which is highly susceptible to mycotoxin contamination. The present study surveyed the incidence and distribution of ochratoxin A (OTA) in cocoa beans over two crop seasons.
Materials and Methods: The cocoa beans samples were collected randomly from farmers across cocoa-growing regions of Ghana. OTA concentrations in the samples were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods following purification on immunoaffinity solid phase column.
Results: The result showed that 21.7% of all samples analyzed were contaminated with OTA at concentrations ranging from 0.01 g/kg to 12.36 g/kg. However, 0.9% and 3.5% of the OTA-positive samples exceeded the OTA maximum limits of 10 g/kg for cocoa beans and 3 g/kg for cocoa powder, set by the Brazilian National Health Surveillance Agency and the European Commission, respectively. During the main and light crop seasons, the highest concentrations of OTA were detected in the Western North region, reaching up to 12.36 g/kg and 3.45 g/kg, respectively. OTA concentrations between the cocoa-growing regions in the main crop season were not significantly different (p > 0.05), however, the light crop season indicated a significant difference (p < 0.05). There was a significant difference (p < 0.05) between the two crop seasons.
Conclusions: The need for regular monitoring and careful adherence to agronomic strategies such as good agricultural practices (GAPs), recommended code of practices (COPs) and good manufacturing practices (GMPs) for the prevention and reduction of OTA throughout the cocoa value chain cannot be over emphasized.

研究目的：可可为极易受真菌毒素污染的农产品之一。本研究针对两个种植季的可可豆展开调查，旨在明确赭曲霉毒素A（Ochratoxin A, OTA）的污染发生率与分布特征。
材料与方法：研究人员从加纳各可可种植区的农户处随机采集可可豆样品，经免疫亲和固相柱净化后，采用液相色谱-串联质谱（liquid chromatography-tandem mass spectrometry, LC-MS/MS）法测定样品中的OTA含量。
结果：研究结果显示，所有受检样品中有21.7%被OTA污染，污染浓度范围为0.01 μg/kg至12.36 μg/kg。其中，0.9%的OTA阳性样品超出巴西国家卫生监督局设定的可可豆OTA最大限量标准（10 μg/kg），3.5%的阳性样品超出欧盟委员会设定的可可粉OTA最大限量标准（3 μg/kg）。在主产季与轻产季中，加纳西北部地区检出的OTA浓度最高，分别可达12.36 μg/kg与3.45 μg/kg。主产季各可可种植区间的OTA浓度无显著统计学差异（p > 0.05）；轻产季各区间则存在显著统计学差异（p < 0.05），且两个种植季之间的OTA浓度亦存在显著统计学差异（p < 0.05）。
结论：在可可全价值链中，为预防并降低OTA污染，需定期开展监测并严格遵循良好农业规范（Good Agricultural Practices, GAPs）、推荐操作准则（Recommended Code of Practices, COPs）以及良好生产规范（Good Manufacturing Practices, GMPs）等农艺策略，这一点无论如何强调都不为过。