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

Standard

The Heavy Metal Tested & Certified standard for non-rice flour — wheat, corn, and other cereal flours — stated as sold. Non-rice cereals do not hyperaccumulate arsenic, so inorganic arsenic is controlled by reflex speciation while total arsenic carries the government cereal ceiling; every limit is the strictest maximum level any credible government sets for the product.

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.

AnalyteHMTc limitBinding basis
Lead (Pb)100strictest government ML (CU)
Inorganic arsenic (iAs)bounded≤ total tAs, measured every lot (see note)
Total arsenic (tAs)200strictest government ML (Paraguay)
Mercury, total (tHg)20strictest government ML (Hong Kong)
Methylmercury (MeHg)bounded≤ total tHg, measured every lot (see note)
Cadmium (Cd)100strictest government ML (EU)
Total chromium (Cr)1000strictest government ML (China)
Hexavalent chromium (Cr-VI)bounded≤ total Cr, measured every lot (see note)
Nickel (Ni)800strictest government ML (EU)
Tin (Sn)250000government read-across (Singapore)
Aluminium (Al)100000government read-across (China)

Every claim analyte is equal at the gate. A product is certified only when every analyte is at or below 100% of its published government floor or disclosed read-across; above the limit, on any metal, it is not certified and carries no mark. 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.

AnalyteEUFDAAU/NZGSOChinaIndiaMercosurIsraelPanamaPhilippinesParaguayThailandVietnamCUHong KongCOHMTcBinds
Lead (Pb)—10000—200—200200200200200200200200100200—100CU
Inorganic arsenic (iAs)————————————————bounded&sup5;species ≤ tAs
Total arsenic (tAs)——1000———2001000——200———500—200Paraguay
Mercury, total (tHg)——————————————20—20Hong Kong
Methylmercury (MeHg)————————————————bounded&sup5;species ≤ tHg
Cadmium (Cd)100—100100—100100100—100100100100100100100100EU
Total chromium (Cr)————1000———————————1000China
Hexavalent chromium (Cr-VI)————————————————bounded&sup5;species ≤ Cr
Nickel (Ni)800———————————————800EU
Tin (Sn)————————————————250000²read-across
Aluminium (Al)————————————————100000²read-across

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.

1 study in the certified-market pool measured lead in Flour across 346 certified-market samples. The pooled distribution centres on a median of 11 ppb and reaches 47 ppb at the 95th percentile. Pompa 2021.

1 study · 346 samples · median 11 ppb · P95 47 ppb

HMTc sets 100 ppb (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 53 ppb, against a government ceiling of 100 ppb. Why lead is limited →

1 study in the certified-market pool measured cadmium in Flour across 346 certified-market samples. The pooled distribution centres on a median of 23 ppb and reaches 77 ppb at the 95th percentile. Pompa 2021.

1 study · 346 samples · median 23 ppb · P95 77 ppb

HMTc sets 100 ppb (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 99 ppb, against a government ceiling of 100 ppb. Why cadmium is limited →

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. (2026). Flour — wheat, corn, and other non-rice: HMTc standard (Standard No. 10.83138/hmtc.std.3.flour-non-rice). Institute of Contaminant Standards. https://doi.org/10.83138/hmtc.std.3.flour-non-rice

© 2026 Institute of Contaminant Standards / Heavy Metal Certified. All rights reserved.

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.