การสำรวจปริมาณการปนเปื้อนของสารตะกั่วในผงโกโก้ที่ผลิตในประเทศไทย A Survey of Lead Contamination Levels in Cocoa Powder Produced in Thailand

Abstract

Objective: To quantify lead residues in 100% pure cocoa powder manufactured from cocoa beans cultivated in Thailand. Methods: A cross-sectional survey was conducted using purposive sampling to collect 15 samples of 100% pure cocoa powder directly from manufacturers or community enterprises, and/or purchased from producers selling on online platforms. All samples were verified to originate from cocoa beans cultivated in Thailand. Lead concentrations were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in accordance with AOAC (2023) reference method 999.10 at Central Laboratory (Thailand) Co., Ltd., with a limit of detection (LOD) of 0.040 mg/kg and a limit of quantitation (LOQ) of 0.075 mg/kg. Results: Eight samples (53.33%) contained no detectable lead (<LOD; 0.040 mg/kg), while lead was detected in the remaining seven samples (46.67%). Of these, three samples yielded quantifiable concentrations of 0.102, 0.101, and 0.096 mg/kg, respectively, and four samples contained trace amounts below the LOQ. All 15 samples remained below the maximum permissible limit of 1.0 mg/kg stipulated by the Ministry of Public Health Notification No. 414 (B.E. 2563). Conclusion: Cocoa powder produced from Thai-grown sources contained lead contamination within national safety standards. However, sustained daily consumption of 5–8 grams from samples with the highest detected lead levels may result in cumulative exposure exceeding the Maximum Allowable Dose Level (MADL) under California Proposition 65 (0.5 µg/day) of the United States. Consumers — particularly children and pregnant women — should monitor their cocoa powder intake and maintain a diversified diet to reduce the risk of long-term heavy metal bioaccumulation. Keywords: Cocoa powder, Lead, Contamination, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Thailand