Darko et al. 2014 — Heavy metals in Ghanaian seasonings

Darko and colleagues measured Fe, Zn, Cu, Cd, Pb, and Hg in 22 mixed and unmixed powdered seasonings purchased from markets in Kumasi, Ghana. Flame atomic absorption spectrometry was used for Fe, Zn, Cu, Cd, and Pb, while mercury was measured by cold-vapour atomic absorption spectrometry. The occurrence finding for HMI target analytes is that Pb was detected across the seasoning set, Cd was detected in a smaller subset, and Hg was below the detection limit in every seasoning. The authors report grouped ranges for mixed and unmixed seasonings and interpret Pb and Cd as the main toxic-metal concern in this sample set.

Key numbers

The highest reported Cd value in unmixed seasonings was 0.9 mg/kg in nutmeg, while the rest of the unmixed seasonings were below the detection limit. In mixed seasonings, the highest Cd value was 0.06 mg/kg. For Pb, unmixed seasonings ranged from 0.6 to 1.8 mg/kg and mixed seasonings from 0.63 to 1.39 mg/kg. The source discusses individual seasoning types and source countries, but this page keeps the evidence at the grouped product-form level.

Methods (brief)

Twenty-two powdered seasonings were purchased from local shops and hawkers in Kumasi after preliminary investigation identified them as commonly consumed seasonings in the metropolis. Samples were grouped as unmixed or mixed seasonings, dried at 45°C for 24 h, cooled, stored in plastic bags, then digested using the Akagi and Nishimura method: about 1 g sample, water, HCl, HNO3:HClO4, and H2SO4, heated at 200°C until clear, filtered, and diluted to 50 mL. Fe, Zn, Cu, Cd, and Pb were determined by air-acetylene flame atomic absorption spectrometry using a Spectr AA 220 instrument; Hg was determined with an HG-5000 automatic mercury analyzer by cold-vapour atomic absorption spectrometry. The source reports Cd and Hg detection-limit language as 0.01 mg/kg and does not speciate mercury.

Implications

This source adds Ghana-market occurrence data for powdered spices, herbs, and seasoning blends, with direct relevance to the spices and condiments-general product routes. Its strongest HMI-target findings are Pb occurrence across all seasonings and Cd occurrence above the source-cited spice comparator in one unmixed seasoning type. Hg should be routed as total mercury context only and specifically as non-detect at the reported 0.01 mg/kg detection limit. The non-HMI essential metals Fe, Zn, and Cu are retained as source context because they were part of the same analytical panel.

Verification notes

• PDF text extracted with pdftotext -layout; the extracted text contained a readable title page, abstract, methods, Tables 1-2, results, conclusion, and references.
• DOI verified from the first page as 10.5897/AJFS2013.1107; DOI, raw handle MFK_10-5897-ajfs2013-1107, and cite-key checks found no existing source page before creation.
• All grouped ranges above were checked against the abstract and Tables 1-2 in the extracted text. The Pb and Cd comparator statements were checked against the Results/Discussion text.
• Units are preserved as reported (mg/kg); no conversion to ppb or µg/kg was performed.
• Speciation: mercury is recorded as tHg because the source measured Hg by cold-vapour AAS and did not report methylmercury or inorganic mercury separately.
• Brand firewall: the paper reports seasoning type/source entries in tables. This page reports grouped mixed/unmixed seasoning ranges and does not attach sampled-product names to contamination values.
• Frontmatter product and ingredient slugs were checked against docs/gpt-collaboration/taxonomy-snapshot.md; no new slug was invented.

Page history

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