Guadalupe et al. 2023 - heavy metals in Peruvian coffee

Guadalupe and colleagues measured inorganic arsenic, cadmium, chromium, mercury, and lead in Peruvian parchment coffee beans and modeled changes through hulling, roasting, and brewing. Cd and Hg were below detection limits, while iAs, Cr, and Pb varied by region, with San Martin showing the highest regional means.

Key numbers

The occurrence survey covered 159 parchment coffee samples collected between September and December 2021 from Amazonas, Cajamarca, Cusco, Huanuco, and San Martin. The varieties were Bourbon, Tipica, Catimor, Caturra, and Pache. The process-modeling subset used 9 parchment-bean samples from Moyobamba, San Martin, processed through hulling, roasting at 210 C for 10 minutes, and espresso, French press, or Italian-machine infusion.

Table 1 reports analytical LODs of 0.005 mg/kg for all five analytes. LOQs were 0.010 mg/kg for iAs, 0.016 mg/kg for Cd, 0.010 mg/kg for Cr, 0.012 mg/kg for Hg, and 0.087 mg/kg for Pb. Recoveries were 99% for iAs, 101% for Cd, 98% for Cr, 101% for Hg, and 99% for Pb.

For the process-modeling subset, the text reports mean parchment-bean concentrations of iAs 1.06 +/- 0.1 mg/kg, Cr 0.39 +/- 0.07 mg/kg, and Pb 0.72 +/- 0.04 mg/kg. Green beans had iAs 0.75 +/- 0.02 mg/kg, Cr 0.08 +/- 0.005 mg/kg, and Pb 0.34 +/- 0.10 mg/kg. Roasted beans had iAs 0.68 +/- 0.05 mg/kg, Cr 0.08 +/- 0.004 mg/kg, and Pb 0.29 +/- 0.01 mg/kg.

Table 2 reports average percentage reductions from parchment bean to infusion. Hulling removed iAs 27.3% (5th 18.4%, 95th 32.3%), Cr 76.2% (5th 71.1%, 95th 82.9%), and Pb 52.6% (5th 48.1%, 95th 57.1%). Roasting removed iAs 11.7%, Cr 9.9%, and Pb 14.7% on average. Brewing extraction averaged 5.9% for iAs, 13.4% for Cr, and 8.2% for Pb.

Table 3 reports parchment-bean regional means. For iAs, means were Amazonas 0.57 +/- 0.21 mg/kg, Cajamarca 0.50 +/- 0.20 mg/kg, Cusco 0.63 +/- 0.19 mg/kg, Huanuco 0.62 +/- 0.09 mg/kg, and San Martin 0.94 +/- 0.17 mg/kg. For Cr, means were 0.08 +/- 0.05, 0.05 +/- 0.02, 0.12 +/- 0.06, 0.08 +/- 0.04, and 0.21 +/- 0.12 mg/kg, respectively. For Pb, means were 0.64 +/- 0.04, 0.64 +/- 0.03, 0.67 +/- 0.03, 0.64 +/- 0.02, and 0.72 +/- 0.05 mg/kg.

Variety effects were significant for Cr but not iAs or Pb. Pache had the highest variety mean for Cr at 0.39 +/- 0.24 mg/kg; Pache also had Pb 0.73 +/- 0.04 mg/kg, while Bourbon had Pb 0.68 +/- 0.05 mg/kg, Catimor 0.69 +/- 0.06 mg/kg, Caturra 0.69 +/- 0.05 mg/kg, and Tipica 0.67 +/- 0.05 mg/kg.

Methods (brief)

The authors analyzed iAs, Cd, Cr, Hg, and Pb in the Soil and Water Research Laboratory at Universidad Nacional Toribio Rodriguez de Mendoza. Validation used ten replicates, blind samples, and duplicate samples. Values below LOD were handled as LOD/2 for risk calculations; Cd and Hg were not detected and were therefore assigned 0.0025 mg/kg for the exposure model.

Coffee-brewing assumptions differed by method: espresso used 17 g ground roasted beans for a 50 mL cup at 92 C, 1.3 bar, and 30 seconds percolation; French press used 7.5 g coffee and 120 mL water at 92 C for 3 minutes; Italian coffee used 35 g coffee and 400 mL water.

Implications

Certification: This is routeable coffee occurrence evidence for Peru-market/source coffee, with separate parchment, green, roasted, and infusion bases. Do not mix the parchment-bean values into roasted-bean or as-consumed coffee-infusion pools without applying the documented process-stage conversions.

Courses: Useful for explaining why commodity-stage and cup-stage measurements differ: hulling drove the largest modeled reduction, especially for Cr and Pb, while brewing transferred less than 10% on average for iAs and Pb.

App: Supports coffee ingredient and product context, but regional Peru data should remain market- and origin-labeled rather than generalized to all coffee.

Wiki pages this source may touch

• coffee
• coffee
• arsenic-inorganic
• cadmium
• chromium
• mercury-total
• lead

Verification notes

The DOI, title, author list, journal, and year were taken from the Foods PDF. The paper reports inorganic arsenic specifically, but mercury is reported only as Hg; this page records it as total mercury and does not infer methylmercury. The text appears to print the Italian-machine iAs infusion mean as 0.42 mg/kg while the adjacent espresso and French means are 0.041 and 0.040 mg/kg; this page does not rely on that apparent decimal anomaly for routing or key occurrence summaries.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.