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E239PreservativeElevated concern

Hexamethylene Tetramine

In plain words

The short version

A formaldehyde-releasing antimicrobial — restricted to traditional provolone cheese in EU.

Why we flag it

It's allowed, but comes with clearer cautions — such as reactions in sensitive people, stricter limits, or contested safety. The Safety section below explains why.

01Origin

Where it comes from

Manufactured by condensation of formaldehyde with ammonia. The 1859 Butlerov synthesis is one of the earliest organic-chemistry textbook reactions. Long history as a pharmaceutical (urinary antiseptic) and an industrial product (solid fuel tablets).

02Usage

How it's used

Permitted in the EU only for traditional provolone cheese, where its slow formaldehyde release suppresses Listeria and Clostridium during long ageing without affecting the characteristic flavor. Maximum residue 25 mg/kg as formaldehyde. Banned for general food preservation.

03Safety

Safety profile

ADI of 0–0.4 mg/kg body weight (as formaldehyde, JECFA). Formaldehyde is a probable human carcinogen — the food exposure from provolone is well below population-thresholds for the inhalational route that drives the carcinogen classification, but the narrow EU permission reflects the tension.

04Properties

Physical & chemical properties

White crystalline powder with mild ammonia odor. Soluble in water. Sublimes at moderate temperature.

05Regulation

Regulation worldwide

Permitted in the EU only for traditional provolone. Banned for general food use in most jurisdictions including the US.

Educational information only. Not medical or dietary advice.