Meter et al. 2019 — Cadmium in Cacao from Latin America and the Caribbean
This comprehensive review, commissioned by the CAF Development Bank of Latin America and Bioversity International, synthesizes the state of knowledge on cadmium accumulation in cacao beans across Latin America and the Caribbean (LAC), covering sources of cadmium contamination in soil, soil properties affecting bioavailability, plant uptake mechanisms, genotypic variability, post-harvest processing effects, and mitigation options. The report’s central finding is that LAC cacao — particularly from Ecuador, Peru, Honduras, and Trinidad — consistently exhibits higher cadmium concentrations than cacao from Africa or Asia, frequently exceeding EU regulatory thresholds that became enforceable in January 2019, posing an existential commercial threat to smallholder farmers producing fine and single-origin cacao in the region.
Key numbers
Cacao bean Cd content (mg/kg, from Annex 1.2 — 21 studies across Africa, Asia, and LAC):
Africa:
- Ghana (Vitola & Ciprovica 2016, n=3): mean 0.02 mg/kg
- Nigeria (Vitola & Ciprovica 2016, n=3): mean 0.02 mg/kg
- Cameroon (Vitola & Ciprovica 2016, n=3): mean 0.05 mg/kg
- Ghana (Amankwaah et al. 2015, n=100): mean 0.05 mg/kg (range 0.005–0.095)
- West Africa (Bertoldi et al. 2016, n=21): mean 0.09 mg/kg
- Ghana (Takrama et al. 2015, n=67): mean 0.27 mg/kg
- East Africa (Bertoldi et al. 2016, n=8): mean 0.51 mg/kg
Asia:
- Indonesia (Assa et al. 2018): mean 0.01 mg/kg
- Asia (Bertoldi et al. 2016, n=8): mean 0.33 mg/kg
- Malaysia (Fauziah et al. 2001, n=50): mean 0.55 mg/kg
- Malaysia (Zarcinas et al. 2004, n=5): mean 0.66 mg/kg (range 0.204–1.680)
LAC:
- Dominican Rep. (Kruszewski et al. 2018): mean 0.13 mg/kg (SD 0.031)
- Ecuador (Vitola & Ciprovica 2016, n=3): mean 0.20 mg/kg
- Bolivia (Gramlich et al. 2017, n=64): mean 0.21 mg/kg
- Ecuador (Acosta & Pozo 2013, n=50): mean 0.35 mg/kg
- Peru (Llatance et al. 2018): mean 0.41 mg/kg
- Central America (Bertoldi et al. 2016, n=10): mean 0.54 mg/kg
- Ecuador (Kruszewski et al. 2018): mean 0.63 mg/kg (SD 0.067)
- Peru (Tantalean et al. 2017, n=40): mean 0.84 mg/kg
- Ecuador (Mite et al. 2010, n=153): mean 0.84 mg/kg (range 0.320–1.800)
- Ecuador (Argüello et al. 2019, n=560): mean 0.90 mg/kg (range 0.03–10.4); 45% of samples exceeded 0.60 mg/kg
- Ecuador (Chavez et al. 2015, n=19): mean 0.94 mg/kg (range 0.020–3.000)
- Ecuador (Barraza et al. 2017, n=31): mean 0.97 mg/kg (SD 0.84, range 0.09–3.51)
- Trinidad (Ramtahal 2015, n=45): mean 0.98 mg/kg (SD 0.248)
- Peru (Arévalo-Gardini et al. 2017, n=70): mean 0.88 mg/kg (range 0.17–1.78); 57% of samples exceeded 0.8 mg/kg
- Honduras (Gramlich et al. 2018, n=110): mean 1.10 mg/kg (SD 0.100)
- Peru (Tantalean et al. 2017, n=40): mean 1.10 mg/kg
- South America (Bertoldi et al. 2016, n=14): mean 1.39 mg/kg (SD 1.089)
- Peru (Cárdenas 2012, n=20): mean 1.55 mg/kg
- Trinidad (Ramtahal et al. 2014, n=43): mean 1.59 mg/kg (SD 0.152)
- Peru/Huánuco (Zug et al. 2019, n=40): mean 2.46 mg/kg (range 0.02–12.5 mg/kg; note: defatted powder of dried beans)
EU regulatory thresholds (EU Reg. 488/2014, enforced Jan 2019):
- Milk chocolate <30% total dry cocoa solids: 0.10 mg/kg
- Chocolate <50% dry cocoa / milk chocolate ≥30%: 0.30 mg/kg
- Chocolate ≥50% dry cocoa solids: 0.80 mg/kg
- Cocoa powder (consumer/ingredient): 0.60 mg/kg
Industry buyer limits for raw cacao beans: 0.5–1.1 mg/kg (not legally mandated; set to protect finished product compliance)
Cadmium partitioning within the cacao plant: concentration order = leaves > pod husks > seed shell > shelled nib.
Methods (brief)
Systematic review of published literature and synthesis of ongoing research projects (at least 28 projects identified across Ecuador, Colombia, Peru, Trinidad, Honduras, and Indonesia). Annex 1 compiles cadmium concentrations from 21 studies using means reported by each study; methodological heterogeneity across studies is acknowledged. Analytical methods in underlying studies include AAS and ICP-MS. Units are mg/kg (equivalent to ppm or mg/kg dry weight for beans).
Limitations
This is a review document, not a primary measurement study; individual study methodologies vary substantially. Sample sizes in the comparative table range from 3 to 560. Many LAC studies focus on hotspot areas, which may overrepresent high-cadmium zones relative to country-wide distributions. The review notes that the contamination problem is localized within countries and regions, not uniform across an entire country. Post-harvest measurement timing and form (whole bean vs. nib vs. powder) differ across studies.
Implications
- Certification: This is a foundational reference for HMT&C’s cocoa/chocolate category. African cacao (particularly West African — mean 0.02–0.27 mg/kg) is reliably well below EU limits. South American cacao, especially Ecuadorian and Peruvian, frequently exceeds 0.80 mg/kg and sometimes exceeds 1.0 mg/kg — posing direct compliance risks for high-cocoa-content products. HMT&C sourcing guidance for chocolate must account for origin. Dominican Republic cacao is notably lower than other LAC origins (mean 0.13 mg/kg) and may warrant separate treatment.
- Courses: Exceptional teaching resource for supply-chain geography × cadmium risk. The Africa vs. LAC comparison is stark and non-intuitive (fine-flavor LAC origins are problematic, commodity West African origins are clean).
- App: Geographic breakdown is directly usable in the
geographic_breakdownsub-field of cocoa’s Cd contamination profile. LAC cacao warrants a higher typical_ppb range than African cacao. - Microbiome: Not applicable.