Canned tomatoes

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.

FSA/Fera measured this ingredient or non-infant-specific food composite in Table 6 of the FS102048 survey. Exact concentration values remain in progress until Table 6 is parsed into structured ingredient rows with less-than and semi-quantitative flags preserved. fsa2016-infant-food-formula-metals-survey

Why this commodity accumulates heavy metals

Canned tomatoes present a metal risk profile dominated by the interaction between tomato acidity and tinplate packaging rather than by high intrinsic accumulation in the tomato fruit itself. Fresh tomatoes are among the lower-accumulating common vegetables for Pb and Cd: the fruit tissue is physically separated from soil contact, the tomato plant does not prioritize metal translocation to fruit, and Pb in particular shows limited phloem mobility, reducing its accumulation in developing fruit even when root-zone concentrations are elevated. Cd accumulation in tomato fruit is detectable but generally low relative to leafy vegetables or root crops. However, tomato sauce and crushed tomatoes are characteristically acidic (pH 3.5 to 4.5), and this acidity creates the dominant contamination pathway in canned form. When acidic tomato product contacts unlacquered tinplate can walls, electrochemical corrosion releases inorganic tin ions into the product. This reaction proceeds continuously in storage, accumulating Sn in the tomato matrix over the product’s shelf life. Studies documented in the canned-food literature confirm that tomato products in unlacquered cans reach some of the highest Sn concentrations observed in commercially sold canned foods Harper et al. 2005, Schafer et al. 1984. FSA/Fera included canned tomatoes in their UK dietary survey fsa2016-infant-food-formula-metals-survey.

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.

Routing

This node is linked from the ingredient index and source routing list.

Contamination Profile State

The machine-readable contamination profile is in_progress. Ingredient-level values belong here once parsed; finished-product values belong on the relevant product-category page.

Ranges by source, region, and variety

The FSA/Fera FS102048 survey measured canned tomatoes as part of a non-infant food composite study in the UK fsa2016-infant-food-formula-metals-survey; exact tabulated values from Table 6 remain in progress pending structured extraction. For intrinsic tomato-fruit metals, the general literature finds Pb typically below 10 ppb and Cd typically below 20 ppb on a fresh-weight basis in non-contaminated growing conditions, with iAs, tHg, and Al also at low levels. The Sn content is the dominant variable and is determined by can type rather than tomato variety or growing region. Published European surveillance and the ATSDR tin profile document Sn concentrations in canned tomatoes and tomato products in unlacquered cans ranging from the tens to hundreds of mg/kg depending on storage time and temperature Harper et al. 2005. Lacquered cans reduce Sn to trace levels. Geographic variation in tomato fruit metals follows soil and irrigation-water quality in the production region (Italy, Spain, California, Turkey are major commercial origins); this variation is secondary to the can-type effect on Sn.

Processing effects

Tomato processing for canning (crushing, heating, acidification, sterilization) does not increase intrinsic tomato-metal concentrations, though it does concentrate metals modestly relative to whole fresh tomatoes on a mass-per-volume basis when water is reduced for purees or pastes. More concentrated tomato products (paste, passata at 6:1 or higher reduction) carry proportionally higher intrinsic Cd and Pb on a per-gram basis. The primary processing effect is the initiation and continuation of Sn migration once the acidic tomato matrix contacts the can wall during and after retorting. Highly reduced tomato products (paste) in contact with unlacquered cans may accumulate Sn faster on a per-gram basis because the lower water content may concentrate the dissolved Sn relative to the food matrix.

Ingredient-derivative risk

Canned tomatoes are a ubiquitous ingredient in retail and food service sauces, soups, pizzas, stews, and condiments. When canned tomatoes are used as an ingredient in a further-processed product (for example, pizza sauce packaged in its own can or jar), the Sn already migrated into the tomatoes is carried forward, and any additional acidic-container contact in the finished product packaging adds further Sn. Products with long thermal processing times or high tomato-fraction inclusion are particularly susceptible. Tomato paste, a concentrate derived from fresh or canned tomatoes, carries a higher intrinsic Cd and Pb per gram than whole canned tomatoes, and its acidity is even more aggressive toward unlacquered tin.

Mitigation options

Sourcing levers

Specifying lacquered-can sourcing from all tomato product suppliers is the single highest-impact lever, eliminating the dominant Sn migration pathway. For intrinsic tomato metals, sourcing from agricultural regions with documented low soil Pb and Cd and clean irrigation water (non-wastewater) reduces the baseline; Cd and Pb in fresh tomatoes are typically low and this lever is of secondary importance relative to can specification.

Agronomic levers

No quantified data on this lever in the current corpus; section will be expanded when relevant evidence is ingested. Fresh tomato Pb and Cd are already low in standard agricultural settings; agronomic interventions provide marginal additional benefit relative to can-type specification.

Processing levers

Specifying lacquered cans is the processing-system lever. For tomato paste and puree, processing that minimizes contact time between reduced tomato and unlacquered metal surfaces (including processing equipment) reduces incidental metal contamination from stainless steel equipment surfaces, where acidic tomato can leach Ni and Cr from equipment alloys during prolonged high-temperature contact.

Formulation levers

Substituting glass-jarred or aseptic-packaged (Tetra Pak or similar) tomatoes for tinplate-canned tomatoes eliminates the Sn migration source entirely. These packaging alternatives are commercially standard and widely available; the substitution is a formulation decision without product-performance trade-offs for most applications.

Testing and QC levers

ICP-MS measurement of Sn in finished canned product, stratified by can type (lacquered versus unlacquered) and by storage duration, provides the most useful QC data. For products using tomato as a major ingredient, testing the tomato input for Cd and Pb provides baseline documentation even if values are expected to be low.

Packaging and storage levers

Lacquered (“enamel-lined”) tinplate cans are the critical packaging specification for this commodity given the high acidity of tomato products. The benefit of lacquering is greater here than for most other canned foods because of the pH-driven acceleration of tin corrosion in tomato matrices. Storage at cool temperatures (below 20°C) and strict shelf-life management reduce cumulative Sn accumulation in unlacquered-can stock. FIFO inventory rotation limits the proportion of product approaching maximum Sn levels Schafer et al. 1984.

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) wet weight. For Pb in vegetables (including tomatoes), the EU limit is 0.10 mg/kg (100 ppb) wet weight. For Cd in vegetables other than leafy or root vegetables, the EU limit is 0.050 mg/kg (50 ppb) wet weight. The Codex Alimentarius general standard for contaminants sets a Sn limit of 250 mg/kg for canned solid foods and 150 mg/kg for canned tomatoes specifically in some national applications. No FDA action level for Sn in canned tomatoes is currently operative; FDA Closer to Zero fda-closer-to-zero addresses Pb in foods for young children rather than 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]*.

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.