Canned corn
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.
| Dimension | Status | What’s there (auditable counts) | What’s missing |
|---|---|---|---|
| D1 Analyte coverage (tier: occasional) | OK | 5/10 HMTc analytes, total n=14 | labeled data-gaps: iAs, Al, Sn |
| D2 Regional coverage | OK | 5 jurisdictions, top PS 25% | — |
| D3 Anthropogenic evidence | GAP | 1 drinking-water; no supply-chain link | link a supply-chain/ hub page |
| D4 Background mechanism | GAP | section present, 0 drivers, 1 upstream source(s) | drivers[] empty |
| D5 Pooling depth | THIN | Pb THIN, Cd THIN, tAs THIN, tHg THIN, Ni THIN, Cr THIN, U THIN | Pb: needs 1 more study(ies); Cd: needs 1 more study(ies); tAs: needs 1 more study(ies); tHg: needs 1 more study(ies); Ni: needs 1 more study(ies); Cr: needs 1 more study(ies); U: needs 1 more study(ies) |
| D6 Speciation | OK | iAs, tAs, tHg declared | — |
| D7 Basis declaration | GAP | 0/10 populated cells declare a basis token | 10 populated cell(s) lack a basis token: Pb, Cd, iAs, tAs, tHg, Ni, Al, Cr, Sn, U |
| D8 Provenance integrity | GAP | 13 claims checked, 13 supported; 2 citations, 0 orphan, 1 foreign | 1 foreign citation(s) not naming canned-corn: fda2022-tds-elements-fy2018-fy2020 |
| D9 Mitigation | OK | 1 cited lever(s), 0 mitigation/ link(s) | — |
| D10 Regulatory coverage | OK | 2 rule link(s), 6 metal(s) covered | unmapped analytes: Ni, Cr, U |
| D11 Standards-readiness | NOT-READY | priority: Pb, Cd, tAs, tHg, Ni, Cr, U; pairing 0 paired, 7 single, 0 unpaired | Pb: THIN, needs 1 more study(ies); Cd: THIN, needs 1 more study(ies); tAs: THIN, needs 1 more study(ies); tHg: THIN, needs 1 more study(ies); Ni: THIN, needs 1 more study(ies); Cr: THIN, needs 1 more study(ies); U: THIN, needs 1 more study(ies); basis: 10 populated cell(s) lack a basis token: Pb, Cd, iAs, tAs, tHg, Ni, Al, Cr, Sn, U |
| Principle balance | flag | consumer-protection 1.00, contamination-reduction 1.00, brand-value 0.00, legal-defensibility 0.50, scale 0.25 | spread 1.00 — starved: brand-value |
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 55, “Corn, canned, drained solids.” fda2022-tds-elements-fy2018-fy2020
Why this commodity accumulates heavy metals
Canned corn (maize) presents a two-pathway metal risk: a low intrinsic pathway from the corn grain itself, and a secondary packaging pathway from the tinplate can. Corn (Zea mays) is among the lowest-accumulating major cereal crops for heavy metals. Its kernel anatomy, particularly the thick pericarp and the relatively impermeable protein matrix of the endosperm, limits uptake and storage of Pb and Cd compared to wheat, rice, or brassica vegetables. Soil cadmium levels have a modest effect on corn grain Cd, but maize is classified as a low Cd accumulator at typical agricultural soil concentrations. Lead uptake from soil into corn grain is also low. The dominant heavy metal concern for canned corn therefore shifts to tin (Sn) migration from the tinplate can interior. Tinplate food cans are manufactured from tin-coated steel; in unlacquered (unlined) cans, the acidic or mildly acidic environment of the food product in contact with the tin coating drives electrochemical corrosion that releases inorganic tin ions into the food. Corn in brine (which is mildly acidic) in contact with unlacquered tinplate can accumulate Sn over shelf life. Storage time and temperature amplify this effect Harper et al. 2005.
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.
| Analyte | Coverage | Typical (ppb) | p95 (ppb) | Confidence | Key sources |
|---|---|---|---|---|---|
| Pb | n=2 | 0 | 0 | low | 1, 2 |
| Cd | n=2 | 0.2–2.0 | 2.1 | low | 1, 2 |
| iAs | data gap | — | — | — | — |
| tAs | n=2 | 0.7–4.7 | 4.9 | low | 1 |
| tHg | n=2 | 0 | 0 | low | 1 |
| Ni | n=2 | 0–44 | 49.5 | low | 1 |
| Al | data gap | — | — | — | — |
| Cr | n=2 | 0 | 0 | low | 1 |
| Sn | data gap | — | — | — | — |
| U | n=2 | 0 | 0 | low | — |
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 “Corn, canned, drained solids” (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.
| Metal | n | min | p10 | p50 | p90 | p95 | max | Schema |
|---|---|---|---|---|---|---|---|---|
| Cd | 3 | 0 | 0.22 | 1.1 | 1.98 | 2.09 | 2.2 | in profile |
| Cr | 3 | 0 | 0 | 0 | 0 | 0 | 0 | in profile |
| Ni | 3 | 0 | 0 | 0 | 44 | 49.5 | 55 | in profile |
| Pb | 3 | 0 | 0 | 0 | 0 | 0 | 0 | in profile |
| U | 3 | 0 | 0 | 0 | 0 | 0 | 0 | in profile |
| tAs | 3 | 0 | 0.72 | 3.6 | 4.72 | 4.86 | 5 | in profile |
| tHg | 3 | 0 | 0 | 0 | 0 | 0 | 0 | in profile |
Ranges by source, region, and variety
The FDA FY2018-FY2020 Total Diet Study reports Cd in canned corn (drained solids) at a median of 1.1 ppb (range 0 to 2.2 ppb, n=3) and total arsenic at a median of 3.6 ppb (range 0 to 5 ppb) FDA 2022. Nickel ranged from 0 to 55 ppb. Pb, Cr, U, and tHg were at or below the reporting limit. These values reflect a low-intrinsic-contamination profile for the corn grain itself. Sn data are not in the TDS FY2018-FY2020 dataset for this food; the ATSDR tin profile documents that unlacquered canned vegetables can accumulate 50 to 200 mg/kg (50,000 to 200,000 ppb) Sn after extended storage, while lacquered cans maintain much lower levels Harper et al. 2005. Geographic and varietal variation in corn grain metals is minimal relative to the can-type driven Sn range.
Processing effects
Canning involves blanching the corn prior to thermal processing; this step may reduce some water-soluble metals. The thermal sterilization step (retorting) does not reduce metal concentrations but does not increase them in the corn matrix. The primary processing-relevant effect is the interaction between the product matrix and the can interior over time: Sn migration is slow at refrigerator temperatures but accelerates at ambient and warm temperatures and with extended storage. Draining and rinsing canned corn before consumption reduces the Sn and other metal content in the aqueous fraction (brine) but does not remove metals already incorporated into the corn kernel tissue. The drained-solids TDS measurement already excludes brine.
Ingredient-derivative risk
Canned corn is used directly as a component in mixed vegetables, soups, salads, and retail products. Its metal contribution to blended products is dominated by the corn-grain fraction for most metals, and by any Sn migration from the can for tin. When canned corn is processed into corn-based products (corn salsas, corn chowders packaged in their own cans), the Sn exposure risk compounds if an additional canning step is involved.
Mitigation options
Sourcing levers
Sourcing corn from regions with documented low soil-Cd and low soil-Pb reduces the grain-derived metal load, though the baseline is already low for this crop. For the canned product specifically, can specification (lacquered versus unlacquered) is the highest-impact sourcing decision.
Agronomic levers
No quantified data on this lever in the current corpus; section will be expanded when relevant evidence is ingested. Soil pH management benefits other crops more than maize given maize’s inherently low metal uptake.
Processing levers
Draining and rinsing canned corn before use reduces dissolved metals (including Sn) present in the brine fraction. This is a practical consumer-level step with no quantified magnitude in the current corpus for Sn specifically.
Formulation levers
Substituting fresh, frozen, or glass-jarred corn for tinplate-canned corn eliminates the Sn migration pathway entirely. This is a high-impact formulation lever for products in which canned corn is used at meaningful inclusion rates.
No quantified data on this lever in the current corpus; section will be expanded when relevant evidence is ingested.
Testing and QC levers
ICP-MS measurement of Sn in finished canned product, particularly from lots with longer projected shelf life or higher storage temperatures, is the most relevant QC test for this commodity. For grain-derived metals (Cd, Pb, As), the low baseline concentrations in corn make this a lower priority than for wheat or rice ingredients.
Packaging and storage levers
Lacquered (“enamel-lined”) tinplate cans substantially reduce Sn migration compared to unlacquered cans, because the polymer coating interposes a barrier between the metal can wall and the food product. Specifying lacquered cans in purchasing contracts is the single most effective intervention for Sn in canned corn. Storing finished cans at lower temperatures (below 20°C) and minimizing shelf life reduces cumulative Sn migration. Product rotation (FIFO inventory management) limits the proportion of product approaching maximum shelf-life Sn levels Harper et al. 2005.
Regulatory limits that apply
The EU eu2023-contaminants-maximum-levels sets a maximum level for Sn in canned solid foods of 200 mg/kg (200,000 ppb); in canned beverages the limit is 100 mg/kg. No specific EU maximum level for Pb or Cd in canned corn as a distinct category is established beyond the general vegetable limits (Pb 0.10 mg/kg, Cd 0.050 mg/kg for vegetables). The Codex Alimentarius general standard for contaminants sets an international Sn limit of 250 mg/kg for canned foods (solid content). The FDA does not currently have a specific action level for Sn in canned vegetables; FDA Closer to Zero fda-closer-to-zero focuses on Pb in foods for young children and does not address Sn.
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]*.
| # | Citation | Year | Type | Used on this page for |
|---|---|---|---|---|
| 1 | FDA 2022. FY2018-FY2020 TDS Elements Analytical Results, FDA Total Diet Study | 2022 | Government dataset | FDA TDS FY2018–FY2020 multi-element occurrence distributions for Corn, canned, drained solids (n=3); detectable concentrations for Cd, Ni, tAs |
| 2 | EL et al. 2020. Aluminum exposure from food in the population of Lebanon, Toxicology Reports | 2020 | Peer-reviewed | LB Al occurrence in Ninety-seven food items collected May–September 2018 from the Beirut retail market (105 sampled; 8 discarded for turbidity), comprising… (n=97) |
| 3 | Al et al. 2018. Environmental exposure assessment of cadmium, lead, copper and zinc in different Palestinian canned foods, Agriculture & Food Security 7:50 | 2018 | Peer-reviewed | Cd and Pb in canned corn samples from the Palestinian market with one Pb exceedance among four brands |
| 4 | Trandafir et al. 2012. Determination of Tin in Canned Foods by Inductively Coupled Plasma-Mass Spectrometry, Polish Journal of Environmental Studies | 2012 | Peer-reviewed | RO/EU Sn occurrence in 14 canned food products (4 pineapple brands, mandarin oranges, fruit cocktail, small whole carrots, mushrooms, 2 peeled-tomato-in-juice brands,… (n=14) |
| 5 | Harper et al. 2005. Toxicological Profile for Tin and Tin Compounds, U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry | 2005 | Government report | Inorganic tin migration from tinplate can coatings; ATSDR toxicological reference for Sn speciation, MRLs, and canned-food Sn release mechanisms relevant to canned corn |
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.
| Commit | Date | Description |
|---|---|---|
| b0f3d38 | 2026-06-12 | batch | corpus rescreen b04 old terminal skips |