How every number on this page is 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 Oyster and shiitake mushrooms (cultivated Pleurotus and Lentinula — cadmium accumulators)’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. 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.
| Analyte | Tier | HMTc limit | Binding basis |
|---|---|---|---|
| Lead (Pb) | Tier 1 | 300 | strictest government ML (EU) |
| Inorganic arsenic (iAs) | Tier 1 | 60 | strictest government ML (Israel) |
| Total arsenic (tAs) | Tier 2 | 300 | strictest government ML (Mercosur) |
| Mercury, total (tHg) | Tier 1 | 30 | strictest government ML (Israel) |
| Methylmercury (MeHg) | Tier 1 | control | mandatory control — no government ML; screened every lot (see note) |
| Cadmium (Cd) | Tier 1 | 150 | strictest government ML (EU) |
| Hexavalent chromium (Cr-VI) | Tier 2 | n/m | not material — controlled analyte (see note) |
| Nickel (Ni) | Tier 2 | 400 | government read-across (EU) |
| Tin (Sn) | Tier 2 | n/m | not material — controlled analyte (see note) |
| Aluminium (Al) | Tier 2 | control | mandatory control — no government ML; screened every lot (see note) |
| Total chromium (Cr) | Tier 2 | control | mandatory control — no government ML; screened every lot (see note) |
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 Oyster and shiitake mushrooms (cultivated Pleurotus and Lentinula — cadmium accumulators). 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.
| Analyte | EU | GSO | Mercosur | Israel | Morocco | Paraguay | Thailand | CH | CO | BA | HK | HMTc | Binds |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lead (Pb) | 300 | 300 | 300 | — | 300 | 300 | 300 | 300 | 300 | 300 | 300 | 300 | EU |
| Inorganic arsenic (iAs) | — | — | — | 60 | — | — | — | — | — | — | — | 60 | Israel |
| Total arsenic (tAs) | — | — | 300 | 1000 | — | 300 | — | — | — | — | — | 300 | Mercosur |
| Mercury, total (tHg) | — | — | — | 30 | — | — | — | — | — | — | — | 30 | Israel |
| Methylmercury (MeHg) | — | — | — | — | — | — | — | — | — | — | — | control&sup4; | screened |
| Cadmium (Cd) | 150 | — | 200 | — | — | 200 | — | — | — | 150 | 500 | 150 | EU |
| Hexavalent chromium (Cr-VI) | — | — | — | — | — | — | — | — | — | — | — | n/m³ | controlled |
| Nickel (Ni) | — | — | — | — | — | — | — | — | — | — | — | 400² | read-across |
| Tin (Sn) | — | — | — | — | — | — | — | — | — | — | — | n/m³ | controlled |
| Aluminium (Al) | — | — | — | — | — | — | — | — | — | — | — | control&sup4; | screened |
| Total chromium (Cr) | — | — | — | — | — | — | — | — | — | — | — | control&sup4; | screened |
All values µg/kg (ppb), as-sold basis. ² no government sets this analyte for this exact product form: the value is read across from the nearest government limit for an analogous product, or — where the Binds column reads occurrence or precautionary — taken from measured occurrence data or set as a precautionary near-neighbour value; the ratchet tightens it as surveillance warrants. 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.
Cite this standard
Pendergrass, K. “Oyster and shiitake mushrooms (cultivated Pleurotus and Lentinula — cadmium accumulators).” In Heavy Metal Tested & Certified (HMTc) Edible Fungi 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.