Peanuts

Completeness scorecard

Deterministic gap audit — no score is composite, no cell is LLM-judged. Each chip is re-derivable by re-running tools/evidence/build-ingredient-scorecard.mjs. review: residuals and missing data are worked autonomously via data/evidence/ingredient-scorecard-review-flags.csv and wiki/completeness-gaps.md.

This ingredient stub was created during the FDA FY2018-FY2020 Total Diet Study element-results ingest so future source ingests have a stable destination for this food matrix. FDA reports this item as TDS Food 48, “Peanuts, dry roasted, salted.” fda2022-tds-elements-fy2018-fy2020

Why this commodity accumulates heavy metals

Peanuts (Arachis hypogaea), also called groundnuts, are unusual among legumes in that their pods develop and mature underground. After fertilisation, the petiole elongates and pushes the developing ovary into the soil, where the pod fills over a period of 60 to 80 days in direct contact with the surrounding soil matrix. This geocarpic growth habit means the seed and its enclosing pod are exposed to soil metals throughout grain fill, in contrast to above-ground legumes (lentils, chickpeas, soy) where seeds fill in pods that hang above the soil surface. Cadmium uptake occurs primarily through root membrane transporters and secondarily through direct contact between the pod surface and the soil; both pathways contribute to seed Cd accumulation. Nickel follows a similar bioavailability-driven uptake pattern, and peanuts are consistently identified as one of the highest dietary Ni contributors in occurrence surveys (flyvholm1984-nickel-content-food-dietary-intake; efsa-nickel-contam-2020).

Cadmium accumulation in peanuts is further documented in authoritative toxicology reviews as a characteristic of oilseed crops grown with Cd-containing phosphate fertilizers or on soils with elevated natural Cd; peanuts and sunflower seeds are specifically named as elevated-Cd crops in the canonical Cd toxicology chapter (nordberg2015-cadmium-chapter). The EFSA Cd opinion of 2009 identifies peanuts as a contributing source in European dietary Cd exposure assessments, reflecting their position in processed snack foods and peanut-containing products (efsa-cadmium-contam-2009).

Heavy metal contamination profile

Per-analyte snapshot derived from the machine-readable contamination_profile in the frontmatter above. data gap indicates the literature has been reviewed for this commodity-analyte combination and no usable occurrence data was found (a finding, not a placeholder). The Key sources column shows the top 2-3 contributing sources by year and sample size, with numbered wikilink aliases.

Synthesis basis and censoring treatment

The lead, total-arsenic, and chromium cells above were resynthesized on 2026-06-11 on a whole peanut-kernel basis, the form in which peanuts enter the ingredient supply chain. Most primary occurrence literature reports kernel concentrations on a dry or as-sold basis; the FDA Total Diet Study figures for dry-roasted salted peanuts (TDS Food 48, n=3 per analyte) are carried as a corroborating as-consumed anchor rather than the headline basis. Inorganic arsenic and total arsenic are kept as distinct analytes and are never derived from one another by a fixed ratio; only the speciated peanut-butter measurement (Hovanec 2004) populates the iAs cell, and the total-arsenic values synthesized here are not propagated to it.

Values below the analytical limit of detection or quantification are treated as left-censored, not as measured zeros. The earlier profile reported lead, total arsenic, and chromium at typical and 95th-percentile values that mis-recorded FDA reporting-limit non-detects as literal zeros. In the FDA TDS composites every dry-roasted-peanut sample fell below the reporting limit for lead (4 µg/kg) and chromium (50 µg/kg), and the total-arsenic distribution collapsed against a 3 µg/kg reporting limit (one of three samples non-detect, the rest pinned near 5 µg/kg). The resynthesis replaces those degenerate cells with the detected kernel distributions from the primary literature, in which all three metals are low but non-zero, with right tails driven by market-sample and contaminated-soil production. The honest floor for lead and chromium is the FDA reporting limit expressed as a left-censored bound (<4 and <50 µg/kg respectively), not zero.

The lead distribution rests on US farmer-stock data (Blair et al. 2017, n=290, regression-on-order-statistics mean 32 µg/kg, 95% upper confidence limit 37 µg/kg, with 94 of 290 samples censored below 20 µg/kg) together with Polish-market surveys (Bielecka et al. 2021, peanut median 82 µg/kg, mean 189 µg/kg; Ćwieląg-Drabek et al. 2025, peanut mean 229 µg/kg, 49 percent below the quantification limit) and Chinese provincial data (Chen et al. 2022, province means 7 to 60 µg/kg, Hebei non-detect). The 95th-percentile anchor of 230 µg/kg is set at the Polish retail mean; documented single-sample maxima (Bielecka 1,354 µg/kg, Ćwieląg-Drabek 818 µg/kg, Blair 640 µg/kg Virginia-Carolina outlier) and a 5,800 µg/kg peanut from a Burkina Faso open market (Bazie et al. 2022) are reported as a separate market-contamination and mining-region stratum and are not folded into the global percentile.

The total-arsenic distribution rests on Blair et al. 2017 (US, ROS mean 28 µg/kg, 109 of 290 censored below 20 µg/kg, single Southwest-region outlier at 410 µg/kg), Bielecka et al. 2021 (peanut median 24 µg/kg, mean 36 µg/kg, range 21 to 71 µg/kg), Chen et al. 2022 (province means 9 to 20 µg/kg), and Belew et al. 2024 (Ethiopia, mean 17 µg/kg, range 1 to 50 µg/kg). The typical band of 5 to 36 µg/kg spans the FDA as-consumed central value to the Polish retail mean; the 95th-percentile anchor of 71 µg/kg is the Bielecka upper range, with the Blair 410 µg/kg Southwest outlier held out of the percentile.

Chromium is reported as total chromium at low confidence; no peanut-kernel hexavalent-chromium measurement exists in the corpus, and no Cr-VI value is inferred from the total. The total-chromium distribution rests on Chen et al. 2022 (province means 234 to 293 µg/kg by ICP-MS), Ćwieląg-Drabek et al. 2025 (peanut mean approximately 230 µg/kg, 4 percent below the quantification limit), Belew et al. 2024 (Ethiopia, mean 145 µg/kg, range 10 to 500 µg/kg), and Alatise et al. 2025 (Nigeria, peanut 720 µg/kg). The typical band of <50 to 290 µg/kg runs from the FDA left-censored floor to the upper Chinese provincial mean; the 95th-percentile anchor of 720 µg/kg is the Nigerian market value. Legume composites that pool peanut with soybean (Wu 2024, legume Cr to 2,600 µg/kg) are soybean-driven and are not adopted as a peanut percentile.

Ranges by source, region, and variety

Peanut Cd concentrations vary substantially by growing region. Sandy, acidic soils with elevated natural Cd, common in parts of West and Central Africa and certain South American growing zones, produce peanuts with higher Cd than peanuts grown on managed US or Argentine soils. US production, concentrated in Virginia, Georgia, Texas, and the Carolinas, generally shows lower Cd than African or some Asian production, but within-US variance by field and season is not negligible. Chinese peanut production covers diverse soil geographies; without origin-specific testing, Chinese peanuts represent an unknown Cd distribution. Runner, Virginia, Spanish, and Valencia types do not show consistent cultivar-level differences in Cd accumulation in the available literature; growing region soil chemistry dominates within-group variance.

Nickel occurrence in peanuts is less origin-dependent than Cd; the EFSA 2020 Ni assessment documents peanuts as a high-Ni food group across European monitoring data regardless of geographic origin, consistent with Ni being a normal soil constituent present in bioavailable form across a wide range of agricultural soils (efsa-nickel-contam-2020). Ni in peanuts therefore does not respond to origin-based sourcing interventions as strongly as Cd.

The FDA TDS FY2018-FY2020 data for dry-roasted salted peanuts (TDS Food 48, n=3) shows Cd at 35-45 ppb (median approximately 42 ppb) and Ni at 400-550 ppb, reflecting US market peanuts predominantly from US-grown sources (fda2022-tds-elements-fy2018-fy2020).

Processing effects

Dry roasting at 160-175 degrees Celsius does not appreciably volatilise inorganic metals (Pb, Cd, Ni). Moisture loss during roasting means dry roasted peanut metal concentrations are slightly higher on a wet-weight basis than raw peanut concentrations from the same lot. Blanching (skin removal post-roasting) removes the seed coat; the seed coat constitutes a small mass fraction, and its contribution to the whole-nut metal burden is minor. Salting (dry surface application) does not add significant heavy metals at standard application levels.

Ingredient-derivative risk

Roasted whole peanuts represent the base form. Peanut butter (see peanut-butter) is a concentrated paste form that carries the same metal profile as the source peanuts. Defatted peanut flour and defatted peanut meal, produced as co-products of peanut oil extraction, concentrate metals above whole-peanut levels because the oil fraction (which is metal-free after refining) is removed while the metal-bearing protein and fibre matrix remains; defatted peanut flour is therefore a higher-risk derivative than whole peanuts or peanut butter on a per-unit-mass basis. Refined peanut oil contains negligible heavy metals after industrial refining (solvent extraction, degumming, bleaching, deodorisation) because metals partition to the aqueous and solid phases.

Mitigation options

Sourcing levers

Specifying peanut origin to prefer US Southeast or Argentine production over unverified African or Asian origin, supported by Cd testing of incoming lots, is the highest-impact sourcing lever for cadmium reduction. For nickel, origin specification does not reduce risk as reliably; lot-level testing is the preferred lever. Codex and EU Cd MLs for peanuts provide a minimum compliance threshold; brand QA programs may adopt tighter internal specifications given the sensitivity of peanut Cd to soil origin.

Agronomic levers

Soil liming in peanut fields to raise pH above 6.5 reduces soil Cd bioavailability and plant uptake. Avoiding application of Cd-contaminated phosphate fertilizers is a preventive measure for growers. These levers are most accessible in contracted supply chains where the buyer has influence over field management.

Processing levers

No validated commercial-scale metal-reduction processing step for whole peanuts is documented in the current corpus. Blanching provides marginal seed-coat removal. The most effective processing lever documented is avoiding co-production of defatted peanut flour in applications where Cd load is a concern, since the defatting step concentrates metals into the meal fraction.

Formulation levers

In composite products (snack mixes, granola bars, protein powders) where peanuts contribute a large share of dietary Ni, substituting a portion of peanut inclusion with seeds or other nuts that are lower in Ni per serving reduces the Ni contribution. For Cd, peanut contribution in multi-ingredient products is diluted by the overall ingredient mix, and the formulation lever is relevant primarily in high-peanut-fraction products.

Testing and QC levers

Lot-level ICP-MS testing of incoming peanuts or peanut-derived ingredients for Cd and Ni is the most direct control. Given that TDS data show consistent Cd detectability at 35-45 ppb and Ni at 400-550 ppb, both analytes are reliably above typical LODs and warrant routine monitoring in quality programmes. Third-party laboratory testing with chain-of-custody documentation provides audit-defensible evidence.

Packaging and storage levers

No quantified data on this lever in the current corpus; section will be expanded when relevant evidence is ingested.

Regulatory limits that apply

Under EU Regulation (EU) 2023/915 (eu2023-contaminants-maximum-levels), the maximum level for cadmium in groundnuts (peanuts) intended for direct human consumption is 0.10 mg/kg fresh weight, and the ML for lead in peanuts for direct human consumption is 0.10 mg/kg (eu-2023-915-cadmium). Codex Alimentarius has adopted a Cd ML for groundnuts intended for further processing that differs from the direct-consumption ML; the relevant Codex document is codex-cadmium-mls. The 17th Session of the Codex Committee on Contaminants in Foods (2024) reviewed trace metal limits for nuts and legumes including peanuts (codex-cccf17-2024). No US FDA action level for Cd or Ni in peanuts applies under the current regulatory framework; FDA Closer to Zero (fda-closer-to-zero) does not currently list peanuts as a priority category. EFSA’s 2020 Ni risk assessment (efsa-nickel-contam-2020) identifies peanuts as a high-Ni food and uses European peanut occurrence data in chronic exposure modelling, providing the regulatory toxicology basis for evaluating Ni exposure from peanut consumption.

FDA TDS FY2018-FY2020 Evidence

The normalized row-level data for this TDS food is stored in data/evidence/fda_tds_fy2018_2020_element_results_samples.csv, with per-food/per-analyte summaries in data/evidence/fda_tds_fy2018_2020_summary_by_food_analyte.csv. Concentrations are retained as FDA reported them, with the reporting-limit column preserved separately; reported zeroes are not rewritten as <LOD unless a source explicitly says to do so. fda2022-tds-elements-fy2018-fy2020

Routing

This node is linked from the ingredient index and the FDA TDS source routing table.

Contamination Profile State

The machine-readable contamination profile is in_progress for analytes measured in the TDS file and pending for profile metals not measured by this source. Ingredient-level values belong here once cross-source synthesis is reviewed; product-category values belong on the relevant product page.

FDA TDS FY2018-FY2020 Occurrence Values

FDA Total Diet Study FY2018-FY2020 reports prepared/composite-food concentration distributions for this ingredient as TDS food “Peanuts, dry roasted, salted” (fda2022-tds-elements-fy2018-fy2020). Values are in ppb-equivalent on the basis FDA reported. The full sample-level data are stored in data/evidence/fda_tds_fy2018_2020_element_results_samples.csv; per-analyte distributions in data/evidence/fda_tds_fy2018_2020_summary_by_food_analyte.csv. These distributions count as one source under persistent-wiki-ingest-rule synthesis discipline; numerical values stay in body scratch until a second independent source is integrated.

Sources

Auto-generated from source-page frontmatter. The “Used on this page for” column is populated by the orchestrator’s POPULATE-SOURCE-LEGEND action; pending entries appear as *[awaiting synthesis]*.

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.