Lima beans

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 42, “Lima beans, immature, frozen, boiled.” fda2022-tds-elements-fy2018-fy2020

Why this commodity accumulates heavy metals

Lima beans (Phaseolus lunatus), also known as butter beans, are a large-seeded legume with a contamination profile that parallels other pulses in its core pathways while differing in some quantitative characteristics due to seed size and starch content. As with lentils and other legumes, cadmium is the metal of primary concern: legumes accumulate Cd from soil through root uptake because the same mobilization chemistry that makes soil nutrients bioavailable to legume root systems also enhances divalent cation uptake. The seed coat of lima beans, as with other pulse crops, carries a higher Cd concentration than the starchy cotyledon interior, so whole dried lima beans have higher Cd than dehulled or split forms. However, the large seed size relative to lentils means that the cotyledon constitutes a larger fraction of total seed mass, which dilutes the overall Cd concentration per gram compared with smaller pulses. Lead in lima beans reaches the edible portion primarily through atmospheric deposition and post-harvest handling; root uptake of Pb is limited by its soil binding characteristics. Nickel in legumes is bioavailable and is the analyte that dominates in the FDA FY2018-FY2020 TDS data, where lima beans (immature, frozen, boiled) showed Ni ranging from 910 to 930 ppb across both samples, a conspicuously high value consistent with legumes’ general affinity for Ni from soil fda2022-tds-elements-fy2018-fy2020.

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.

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 “Lima beans, immature, frozen, boiled” (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.

Ranges by source, region, and variety

The FDA FY2018-FY2020 Total Diet Study measured lima beans (TDS Food 42, “Lima beans, immature, frozen, boiled”) with only n=2 composites; both showed Ni at 910 and 930 ppb respectively, U at values of 0 and 2 ppb at the range endpoints, and Cd, Pb, Cr, tAs, and tHg at or below the reporting limit 1. The n=2 sample count severely limits distributional inference from the TDS for this commodity; the Ni values are consistent with the general pulse literature identifying legumes as dietary Ni contributors, but whether Cd is genuinely at the reporting limit in this matrix or whether the sample count is too small to represent the population variance cannot be determined from two composites. US-grown lima beans, produced primarily in California, are from agricultural soils that are generally well-characterized; imported lima beans from other growing regions would carry geographic soil-metal variability not captured in the TDS. The “immature, frozen” format captured by the TDS reflects the market form most commonly consumed in the US; dried mature lima beans would have different moisture content and thus different metal concentrations on a wet-weight basis.

Processing effects

The frozen boiled form measured in the TDS represents a commercially prepared product that has undergone blanching before freezing. Blanching (brief exposure to hot water or steam) removes some surface-soluble metals from immature bean pods but affects the interior seed minimally for metals already absorbed into plant tissue. Cooking (boiling) of frozen or dried lima beans in water provides an opportunity for metal leaching into the cooking water; discarding cooking water reduces the metal burden of the edible bean. Soaking dried lima beans before cooking, as is common practice for mature dried beans, and discarding soak water has the same effect documented for lentils: Cd and Ni in the soak water carry away a fraction of the total metal content. Canned lima beans are subject to Sn migration from tin-lined cans, as documented for canned pulses generally; this pathway is not captured by the TDS data for the frozen boiled form.

Ingredient-derivative risk

Lima bean flour and lima bean protein concentrates are not mainstream commercial ingredients at present but would carry metal profiles proportional to the source bean, with Ni being the analyte of most concern given the TDS data. Canned lima beans represent a different format from the frozen form characterized here; the Sn pathway would be relevant for the canned form if unlacquered tin-plate is used. Mature dried lima beans (larger seed, fully developed starchy cotyledon) may differ somewhat in metal concentration from the immature frozen form measured in the TDS.

Mitigation options

Sourcing levers

Sourcing from producers with documented soil Cd monitoring provides the primary lever for Cd. Geographic origin documentation enables assessment of whether Ni-rich soils (a common property of legume-growing regions with high clay content) contribute to elevated Ni. US California-origin lima beans from known agricultural regions provide traceability.

Agronomic levers

Soil pH management above 6.5 reduces Cd bioavailability. Selection of lima bean varieties with lower Ni accumulation is a potential lever that has not been systematically characterized in the current corpus.

Processing levers

Soaking dried lima beans in water (for mature dried forms) and discarding soak water reduces Cd and Ni content. Blanching before freezing (applied commercially) provides a partial surface-metal reduction. Cooking in ample water and discarding cooking water reduces the metal burden further.

Formulation levers

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

Testing and QC levers

Given the high Ni values (910 to 930 ppb) in the TDS data, Ni testing of incoming lots is warranted for products where Ni is a concern. EFSA’s nickel risk assessment identifies legumes as dietary Ni contributors, and the TDS values for lima beans are at the upper end of the range seen for legumes. Cd testing is also appropriate given the general pulse Cd accumulation pathway; the absence of detectable Cd in the two TDS composites should be verified against additional sources before treating lima beans as low-Cd.

Packaging and storage levers

Frozen lima beans in plastic pouches are not subject to Sn migration. Canned lima beans would require lacquer-lined can specifications to reduce the Sn migration pathway.

Regulatory limits that apply

EU Regulation 2023/915 sets a maximum level for Cd in dried legumes (pulses) of 0.10 mg/kg wet weight eu-2023-915-cadmium; this limit is applicable to dried lima beans as placed on the market. For fresh or frozen lima beans, the applicable Cd limit would follow the vegetable framework rather than the pulse framework; the EU typically applies 0.10 mg/kg for fresh pulses with pods consumed. The Pb limit for dried legumes is 0.10 mg/kg wet weight eu2023-contaminants-maximum-levels. No specific regulatory limit for Ni in legumes exists in current EU or US regulatory frameworks, though EFSA has established a tolerable daily intake for Ni of 13 µg/kg body weight per day based on sensitized individuals as the most sensitive population 1. Codex Alimentarius sets a maximum of 0.10 mg/kg for Cd in pulses codex-cadmium-mls.

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.