Root and tuber vegetables — HMTc Standard

How every number on this page is set

CELL RESOLUTION RULE, applied uniformly across all eight rows. (R1) Where a credible sovereign government writes a maximum level for this product form in this row's native basis, the cell is the strictest such value and is tagged regulatory-alignment. (R2) Where the exact cell is unregulated but a credible sovereign writes a maximum level for the SAME commodity in an adjacent form or basis, the cell is a disclosed read-across from that named row, taken at face value only where face value is the conservative (stricter) direction. (R3) Where no sovereign instrument reaches the commodity at all, the cell is a CONTROL: testing is mandatory, an escalation rule is published, and no number is invented. Aluminium is a control in all eight rows because no jurisdiction regulates aluminium as a produce contaminant. Hexavalent chromium is a substantiated not-material determination wherever a total-chromium parent is published for the row and a control wherever it is not; it is never a published number. Methylmercury is a substantiated not-material determination in all eight rows, bounded by the published total-mercury ceiling, because terrestrial produce has no aquatic methylation compartment. TAXONOMY LUMPING IS DISCLOSED, NOT SILENTLY RESOLVED: several sovereign instruments split classes that this taxonomy carries as a single row (fruiting versus bulb versus brassica versus legume vegetables inside non-root-vegetables; temperate versus tropical roots and tubers inside root-tuber-vegetables; table olives versus pickled cucumbers versus fermented brassicas inside pickled-fermented-vegetables; pome, stone, citrus and berry fruit inside fresh-fruit). Because one published HMTc value must be met by every product in the row, each such row binds the strictest value applicable to any member, which is materially stricter than law for the looser members. Every collapsed split is named in that row's scope_note, and the recommended taxonomy splits are recorded as outstanding items rather than resolved by picking a looser residual-class value, which would let HMTc certify a lot that is unlawful in a market of sale.

Master Limit Table

All values in ppb (µg/kg), as-sold basis. 6 of 11 analytes carry a firm ceiling; the remainder are governed by mandatory control or reflex-speciation screening with no standalone number, itemised in the derivation below. A brand meeting every firm value on a like-for-like basis, and passing every control, qualifies for the mark.

Tier 1 (Pb, iAs, Hg, MeHg, Cd) are zero-tolerance toxics with no established safe threshold. Tier 2 (tAs, Cr-VI, Ni, Sn, Al, Cr) carry a 150% transitional allowance under the program’s Status A–E framework.

Derivation — every government’s number, side by side

The full derivation for Root and tuber vegetables. Each row lists every government maximum level in force worldwide, converted to the as-sold basis; the HMTc limit is the strictest of them, and the last column names which sovereign law binds. A blank cell means that government sets no limit for this analyte in this product.

All values µg/kg (ppb), as-sold basis. ² no government regulates this analyte for this exact product form: the value is a disclosed read-across from the nearest applicable government maximum, and the derivation names the instrument it comes from. It is never taken from occurrence data. After publication the standards ratchet may tighten it, using certified-lot results only. ³ not material in this matrix: controlled by reflex speciation or packaging control, not a standalone number. &sup4; no sovereign maximum exists for this analyte in this product, but a credible exposure pathway does — it is screened on every lot under ALARA against the tightest analogous reference, not assigned an invented number.

Occurrence and derivation rationale

For each analyte on the panel: what the peer-reviewed and survey literature measured in this category, cited one way to the Heavy Metal Index, and the Method v2.0 reasoning behind the certification limit — including, where no government sets a number, why the program sets one anyway. Occurrence figures are literature findings; the derivation is the certifier's.

Cite this standard

Pendergrass, K. “Root and tuber vegetables.” In Heavy Metal Tested & Certified (HMTc) Fruits, Vegetables, and Produce standard, version 1.0. Institute of Contaminant Standards (ICS), 2026. DOI: registration pending.

The literature baseline for every analyte is maintained independently at the Heavy Metal Index. This certification standard applies those findings; the two are kept editorially separate by design.