E239 - Hexamethylene tetramine

At a glance

• What it is: a synthetic preservative also called hexamine or methenamine.
• What it does: helps prevent spoilage by slowly releasing antimicrobial formaldehyde in acidic conditions.
• Where it’s used: in the EU, only certain Provolone cheeses may use it, and only at very low levels.
• Label names: “hexamethylenetetramine,” “hexamine,” “methenamine,” or “E239.”
• Dietary notes: not made from animal products.

Why is Hexamethylene tetramine added to food?

Food makers use E239 to control spoilage bacteria and some molds in specific cheeses that develop in acidic conditions. In acid, hexamethylenetetramine splits and releases a small amount of formaldehyde, which is the actual antimicrobial agent in the food matrix.¹ This controlled release helps protect the food while keeping levels low.

What foods contain Hexamethylene tetramine?

Rules in the European Union allow E239 only in Provolone cheese, and only up to a very small maximum level that is calculated as residual formaldehyde in the final product.² Outside this narrow use, it is uncommon to find E239 on ingredient lists of modern foods in regulated markets.

If you are checking a label, look for “hexamethylenetetramine,” “hexamine,” “methenamine,” or “E239.”

²

What can replace Hexamethylene tetramine?

Depending on the product and process, makers may use other preservative strategies instead of E239, such as:

• Natural antimicrobials for cheese like nisin or natamycin.
• Weak-acid preservatives such as sorbic acid and potassium sorbate.
• Preservatives for acidic foods like sodium benzoate.
• Enzymes in cheese like lysozyme.
• Process controls such as salt, low moisture, and acidity management with citric acid.

How is Hexamethylene tetramine made?

Hexamethylenetetramine is produced by reacting ammonia with formaldehyde in water, followed by crystallization and drying to give a stable, cage-like molecule.¹ In the EU, it must also meet official purity criteria set for food additives before it can be used.³

Is Hexamethylene tetramine safe to eat?

Regulators manage safety by allowing E239 only for a single use (certain Provolone cheeses) and by setting a strict maximum level expressed as residual formaldehyde in the finished cheese.² This approach reflects the fact that the preservative effect comes from a small amount of released formaldehyde in acidic foods, while limiting consumer exposure.¹

As with all approved additives, products using E239 must comply with these legal limits; foods on the market that meet them are considered acceptable for the general population in those jurisdictions.²

Does Hexamethylene tetramine have any benefits?

• It helps certain traditional cheeses resist spoilage and surface defects during maturation.
• It can extend shelf life in specific, legally allowed applications, reducing food waste.

Who should avoid Hexamethylene tetramine?

• People who know they are sensitive to formaldehyde may wish to avoid E239-treated foods, since the additive can release small amounts of formaldehyde under acidic conditions.⁴
• Anyone following a no-added-preservatives diet can choose cheeses labeled without E-numbers or preservatives.

If you have asthma, severe chemical sensitivities, or other respiratory conditions, discuss any concerns about formaldehyde exposure with a healthcare professional.⁴

Myths & facts

• “It’s the same as adding formaldehyde directly.” Not exactly. E239 is a separate compound that can release small amounts of formaldehyde in acidic foods; its use is strictly limited and controlled.
• “It’s common in cheese.” False. In the EU, it is allowed only in certain Provolone cheeses and at very low levels.
• “It’s banned everywhere.” No. Some jurisdictions allow very limited uses with strict maximum levels.

Hexamethylene tetramine in branded foods

E239 is rare on modern labels. If present, it will appear as “hexamethylenetetramine,” “hexamine,” “methenamine,” or “E239.” You are most likely to see it, if at all, on certain Provolone cheeses. If you prefer to avoid it, choose cheeses with short, additive-free ingredient lists.

References

Footnotes

1. Hexamethylenetetramine (Compound Summary) — PubChem, National Institutes of Health. https://pubchem.ncbi.nlm.nih.gov/compound/Hexamethylenetetramine ↩ ↩² ↩³

2. Regulation (EC) No 1333/2008 on food additives — Annex II (Union list, conditions of use). EUR-Lex. https://eur-lex.europa.eu/eli/reg/2008/1333/oj ↩ ↩² ↩³ ↩⁴

3. Commission Regulation (EU) No 231/2012 laying down specifications for food additives. EUR-Lex. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩

4. Toxicological Profile for Formaldehyde — Agency for Toxic Substances and Disease Registry (ATSDR). https://www.atsdr.cdc.gov/toxprofiles/tp111.pdf ↩ ↩²