1,4-Heptonolactone
A cyclic acid derived from heptonic acid, once used as an acidity regulator. It holds an E-number but is not on the current UK or EU positive list of permitted food additives.
E370 is not currently authorised for use in food in the UK or EU. Its presence in any food product would be unlawful under the positive-list system. No safety evaluation has been completed by EFSA or the FSA that would clear it for use.
What is it?
1,4-Heptonolactone is the cyclic ester (lactone) formed when heptonic acid cyclises. It is a water-soluble, slightly acidic compound. It was assigned an E-number during earlier European food additive cataloguing work but was not included in the current consolidated positive list drawn up under EU Regulation 1333/2008.
What does it do?
As an acidity regulator it would lower or buffer pH in a food system, releasing acid slowly as the lactone ring opens in the presence of water. This is the same general mechanism used by glucono-delta-lactone (E575), but E370 was never widely adopted commercially.
Where you will see it
E370 has no currently authorised food uses in the UK or EU. Historically it was referenced as a potential acidulant, but it is not found in mainstream food products on the UK market. Because it is not on the positive list, manufacturers cannot legally add it to food. You would not expect to see '1,4-heptonolactone' or 'E370' on any UK product ingredient label.
What the science says
Regulatory status: not authorised
Under the EU and UK positive-list system, only food additives explicitly listed in Annex II of Regulation 1333/2008 (assimilated into UK law post-Brexit) may be used in food. E370 does not appear in Annex II. An E-number alone does not confer permission; it is simply a numbering code. Because E370 was never granted authorisation under the consolidated positive list, no maximum permitted level, no acceptable daily intake, and no approved food categories exist for it.
The EU positive list for food additives (Annex II to Regulation 1333/2008) does not include E370. Under the positive-list system, any additive absent from Annex II is not permitted for use in food in the EU or, post-Brexit, in Great Britain under retained/assimilated law.
The UK FSA approved additives list, derived from the assimilated EU Regulation 1333/2008, sets out the only additives that may legally be used in food placed on the market in Great Britain. E370 is not included.
Toxicological data
EFSA has not published a full safety evaluation of 1,4-heptonolactone as a food additive. The Scientific Committee on Food (SCF) catalogued it historically, but no formal opinion establishing an ADI or confirming safety was issued. The absence of a completed safety dossier is part of why it was not carried onto the positive list.
No EFSA food additive re-evaluation opinion for E370 has been published as part of the systematic re-evaluation programme (Regulation EU 257/2010). The compound was not included in the re-evaluation schedule because it lacks current authorisation.
Where it stands with the regulators
Who should be careful
Because E370 is not currently permitted in UK or EU food, no authorised use exists and no population group should expect to encounter it as an intentionally added ingredient. If you see 'E370' or '1,4-heptonolactone' listed on a product label, that would indicate a potential compliance issue worth raising with the FSA.
The honest read
E370 sits in a small category of E-numbers that were catalogued historically but never made it through the modern authorisation process. The number exists; the permission does not. This is not an additive that has been evaluated, cleared and then restricted. It simply was not put forward with a sufficient safety dossier to earn a place on the positive list. The practical upshot is that you will not encounter it in legitimately sold UK food.
Related additives
Common questions
Is E370 banned in the UK?
E370 is not on the UK or EU positive list of permitted food additives, which means it cannot legally be added to food. It was never formally authorised under the consolidated rules set out in EU Regulation 1333/2008, now assimilated into UK law. 'Not permitted' is the accurate description.
Does having an E-number mean an additive is approved for use?
No. An E-number is a reference code assigned during cataloguing, not a stamp of approval. Only additives that appear in Annex II of Regulation 1333/2008 (the positive list) may legally be used in food. E370 has a number but no current authorisation.
What foods contain E370?
None, under current UK and EU law. E370 is not an authorised food additive, so no food category has a permitted level for it. It should not appear as an ingredient in any product legally on sale in the UK.
Is E370 vegan?
1,4-Heptonolactone is a synthetic organic compound with no animal-derived ingredients. However, the question of vegan status is academic given that it is not a permitted food additive and should not be present in UK food products.
Sources
- EU Regulation 1333/2008 on food additives, consolidated text (Annex II positive list)
- UK Food Standards Agency: Approved additives and E numbers
- EFSA food additives re-evaluation programme overview
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