Flour, wheat, corn, and other non-rice, HMTc Standard

How limits are set

The standard for each analyte is the strictest maximum level set by any credible government regulator, among them the European Union, Codex Alimentarius, the US FDA, Australia/New Zealand, the Gulf states (GSO), and the national authorities of every jurisdiction that regulates the product, converted into Flour: wheat, corn, and other non-rice’s own as-sold basis. It is a lookup of sovereign law, carrying at most one disclosed basis conversion where the law is written in another basis, and an explicit read-across where no government regulates the exact product. A certified product sits at or below every applicable sovereign limit at once.

Where no government regulates the exact product for an analyte, the standard does not go blank or invent a number: the limit is read across from the nearest government value for an analogous product, so a certified product still sits at or below a real sovereign limit. The ratchet tightens these after publication as surveillance warrants.

Master Limit Table

All values in ppb (µg/kg), as-sold basis. 8 of 11 analytes carry a firm ceiling; the remaining 3 are toxic species bounded by their parent totals (species ≤ total, measured on every lot), so every analyte carries an enforceable ceiling. A brand meeting every value on a like-for-like basis qualifies for the mark.

Tier 1 (Pb, iAs, Hg, MeHg, Cd) are zero-tolerance toxics with no established safe threshold. Tier 2 (tAs, Cr, Cr-VI, Ni, Sn, Al) carry a 150% transitional allowance under the program’s Status A–E framework. Inorganic arsenic (iAs) is the arsenic species that binds on rice: rice hyperaccumulates arsenic, and every government that regulates it does so by product form (milled 150, parboiled/husked/rice-flour 250, rice products 300, rice drinks 30). Non-rice cereals do not hyperaccumulate arsenic, so iAs is not-material there and total arsenic (tAs) carries the government cereal ceiling instead. Mercury is limited as total mercury (tHg); methylmercury (MeHg), which no government regulates in grain, is bounded by the total-mercury ceiling. Hexavalent chromium (Cr-VI) is controlled by reflex speciation on total chromium, not an invented number. Tin (Sn) is material only for canned product, which routes to the canned-goods category. Aluminium (Al) has no government grain maximum in any jurisdiction.

Derivation

The full derivation for Flour: wheat, corn, and other non-rice. 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: measured but with no standalone number, controlled by packaging control or by the total-metal screen, not an invented value. &sup5; a toxic species governed by and bounded by its parent total (for example inorganic arsenic ≤ total arsenic): the species can never exceed the total, so the total ceiling is the species ceiling. The total metal is measured on every lot and the species is established at baseline; no separate species ceiling is published. On ongoing lots the species is speciated whenever the total exceeds its limit.

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.

Risk Flag

On the published occurrence literature to date, Flour, wheat, corn, and other non-rice shows no systematic gap between typical market levels and the limit, the limit being the strictest government maximum for the product (Method v2.0). Certification is decided on a product’s own tested result, not on a distribution; an individual lot or supplier can still exceed a limit.

See the cross-category summary of the ingredients that most often struggle.

Cite this standard

Pendergrass, K. “Flour: wheat, corn, and other non-rice.” In Heavy Metal Tested & Certified (HMTc) Grains, Cereals, and Rice Products 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.