Famurewa et al. 2023 - Metals and pesticide residues in coconut oil sold in Nigeria

Famurewa et al. measured toxic metals, trace minerals, pesticide residues, vitamins, and amino-acid profiles in three coconut oil samples associated with the Nigerian market. The metal analysis used ICP-OES after acid extraction/digestion and reported concentrations in mg/kg oil. Lead, cadmium, total arsenic, nickel, and aluminum were detected in all three oils, while mercury was not detected. The imported oil had higher toxic-metal concentrations than the two locally produced Nigerian oils, but all reported toxic-metal values were below the FAO/WHO reference limits cited by the authors.

Key numbers

Toxic metals in coconut oil

Table 2 reports mean +/- SEM in mg/kg oil for three determinations. COI is the imported coconut oil sold in Nigeria, COS is the southern Nigeria local oil, and CON is the northern Nigeria local oil.

The paper states that COI was significantly higher than COS and CON for each detected toxic metal, while COS and CON were not significantly different from each other. Mercury was undetected in all three oils.

Trace minerals with existing metal-page relevance

Table 1 reports mean +/- SEM in mg/kg oil. Selected trace elements with local metal pages were:

The same table also reports calcium, magnesium, potassium, sodium, phosphorus, sulfur, and boron, but those nutrients are not used here as heavy-metal routing fields.

Pesticide residue context

Table 6 reports nineteen pesticide residues in ug/kg oil. The lowest reported residue was perthane at 0.03 +/- 0.01 ug/kg in COI, and the highest was gamma-HCH at 7.10 +/- 0.01 ug/kg in CON. The source states that all pesticide residue values were below the listed EU, FAO/WHO, Thailand, China, or literature MRL comparators where a comparator was available.

Methods (brief)

Samples were purchased between July and August 2021 and stored frozen until analysis. For metal analysis, 2 g of oil was mixed with 80 mL of 0.1 M HCl, stirred, centrifuged, filtered through a 1.0 um cellulose ester membrane, acidified with concentrated nitric acid, and injected into an ICP-OES instrument. The paper states that each analysis was carried out in triplicate and reports values as mean +/- SEM for metals.

Pesticide residues were measured by HPLC-DAD after acetonitrile extraction. Vitamins were measured by HPLC with UV detection, and amino acids were measured after acid hydrolysis and derivatization. The metals are total-element measurements; arsenic is total arsenic, mercury is total mercury/non-detect by this method, and chromium is total chromium rather than Cr(VI).

Implications

Certification: This source provides occurrence evidence for coconut oil sold or produced for the Nigerian market. The values are usable as coconut-oil and cooking-oil context, but they should not be pooled into a United States market benchmark without a documented cross-market decision.

Courses: The paper is useful for teaching a paired local/imported oil comparison: the imported oil carried higher Pb, Cd, total As, Ni, and Al concentrations, while all values remained below the source-cited limits.

App: Adds coconut-oil category context for total Pb, Cd, total As, total Hg non-detect, Ni, Al, and total Cr. The source does not provide brand-level evidence for public app use, and brand/manufacturer names should remain excluded.

Microbiome: Not addressed.

Wiki pages this source may touch

• lead
• cadmium
• arsenic-total
• mercury-total
• nickel
• aluminum
• chromium
• cobalt
• copper
• iron
• zinc
• manganese
• beryllium
• silver
• molybdenum
• gold
• coconut
• vegetable-oil
• vegetable-oils
• cooking-oils-other

Verification notes

• PDF metadata, first-page journal header, and article footer identify the paper as Measurement: Food 10 (2023) 100082 with DOI 10.1016/j.meafoo.2023.100082.
• The PDF states open access under CC BY-NC-ND 4.0.
• The raw PDF names a manufacturer for the imported sample, but this source page omits brand/manufacturer attribution under the wiki brand firewall and summarizes the findings at category level.
• sample_n: 3 counts the three oil samples. The source separately reports triplicate determinations for the analytical measurements.
• The source reports arsenic and mercury as elemental ICP-OES results without speciation; frontmatter therefore uses tAs and tHg, and the page does not route these values as inorganic arsenic or methylmercury.
• The source compares values to FAO/WHO reference limits for oils but does not conduct a dietary exposure or health-risk assessment.

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.