Bravo et al. 2024 — Cadmium in cacao and artisanal chocolate, Arauca Colombia
This field study characterized cadmium (Cd) contamination in cacao crops and artisanal chocolates across 180 farms in the Arauca Department of Colombia, a growing cacao-producing region in the Orinoco basin. The study documents a north-south gradient in Cd concentration driven by proximity to the Andes, with higher Cd levels in farms closer to the mountain foothills. Average Cd in cacao seeds (n=14 farms) was 0.78 mg/kg; average Cd in artisanal chocolates (n=6) was 1.10 mg/kg, exceeding the EU maximum limit of 0.80 mg/kg for dark chocolate (Regulation EU 488/2014). The study used macro-X-ray fluorescence (MXRF) technology for in-situ measurement of Cd in chocolate bars, validated against laboratory ICP-MS results on cacao seeds.
Key numbers
Cacao seeds: mean Cd 0.78 mg/kg (wet weight or dry weight not explicitly stated; method context suggests dry-weight basis), range across the 14 sampled farms not fully tabulated in the available text but individual farm values ranged from below detection to above 1 mg/kg. Artisanal chocolate: mean Cd 1.10 mg/kg (n=6), all six samples above the EU 0.80 mg/kg limit for dark chocolate. North-south gradient: farms in Arauquita municipality (closest to Andean foothills) showed higher Cd than farms in Tame or Saravena. EU maximum limits applied as comparison: 0.80 mg/kg for chocolate with ≥50% dry cocoa solids; 0.30 mg/kg for milk chocolate.
Analytical method for seeds: ICP-MS after acid digestion (details reported in supplementary methods). Analytical method for chocolate: MXRF (portable macro-XRF), validated against ICP-MS on certified reference materials. LOD for MXRF reported as approximately 0.1 mg/kg Cd.
Methods (brief)
Survey of 180 farms across four municipalities in Arauca Department. GPS coordinates recorded for all farms. Subsamples of fermented, dried cacao seeds collected from 14 farms. Six artisanal chocolate bars purchased from local producers. Cd measured in seeds by ICP-MS; Cd in chocolate by MXRF with ICP-MS validation. Spatial analysis using GIS to map Cd distribution and identify geographic gradients.
Limitation: seed sample size (n=14 farms out of 180 surveyed) is modest; farm selection criteria for seed sampling not fully described, potentially introducing selection bias toward higher-Cd farms.
Implications
Certification: Arauca-origin cacao is a documented high-Cd source; supply chains sourcing Colombian cacao without origin traceability should treat Arauca as a risk flag. The 6/6 exceedance rate for EU limits in artisanal chocolate is relevant to HMT&C chocolate and chocolate-containing product categories.
Courses: Useful for supply-chain modules covering how Andean geology drives Cd gradients in South American cacao and why origin documentation matters for regulatory compliance.
App: Supports flagging Colombian cacao (especially Andean-proximal origins) as high-Cd risk; geographic_breakdown on the cocoa ingredient page should include Colombia (Arauca) range.