Boric acid (E284)

Boric acid is the preservative the food industry lists as E284. In our table it is moderate risk: it takes 15 points off the additive subscore, a third of a product's score (about 5 of the 100).

What Boric acid does to a score

A packaged food's additive subscore starts at 100 and loses points for each additive on the label; that subscore is a third of the final score. Boric acid takes 15 points off the additive subscore, a third of a product's score (about 5 of the 100), and a child under 6 sees it one class higher again. Scan the pack in Sito and the score you get is the one for your own child's age, with this additive named in the reasons. How we score has the whole method.

What the sources found

Every classification in our table comes from the citations below, and nothing else. Each finding is our one-line summary of what the source concluded, with the source and reference beside it.

• EFSA 10.2903/j.efsa.2013.3407 (EFSA Journal 2013;11(10):3407)
  Group ADI 0.16 mg boron/kg bw/day established (NOAEL 9.6 mg boron/kg bw/day from a rat developmental study, uncertainty factor 60); male reproductive system adversely affected in rats, mice and dogs; boric acid and sodium tetraborate do not raise concern for genotoxicity. Exposure from the additive use at the highest mean: children 0.04 mg boron/kg bw/day. At the 95th percentile for consumers only: children 0.56 vs adolescents 0.37, adults 0.13, elderly 0.15 — children highest, 3.5x the ADI, the basis of the child flag. The Panel concluded regular exceedance of the ADI is unlikely given the caviar-only authorisation.
• EU law Commission Regulation (EC) No 790/2009 (1st ATP to CLP Regulation (EC) No 1272/2008), index 005-007-00-2 (boric acid) and 005-011-00-4 (disodium tetraborate); Commission Delegated Regulation (EU) 2021/849
  Boric acid and disodium tetraborate carry the EU harmonised classification Repr. 1B, H360FD ('may damage fertility; may damage the unborn child'). Regulation (EU) 2021/849 deleted the boron-specific concentration limits, so the generic 0.3% limit for Repr. 1B applies since 2022-12-17. A hazard classification of the substance, not a food rule — CLP labelling does not apply to food sold to the final consumer — but it is the named regulatory reflection of the developmental hazard that keeps this row at mid rather than low. The same substances have been on the REACH Candidate List as SVHCs since 2010-06-18.
• EU law Regulation (EC) No 1333/2008 Annex II, food category 09.3 (fish roe): E 284 boric acid, maximum 4 000 mg/kg (expressed as boric acid), only sturgeons' eggs (caviar)
  The single EU-authorised food use, in force: preservative in sturgeon caviar at up to 4,000 mg/kg expressed as boric acid. An authorisation, not a ban.
• FDA eCFR search of 21 CFR — boric acid appears only in indirect/food-contact sections (§176.180, §178.2010, §178.3130, §175.105); no direct food-additive or GRAS listing
  Not permitted as a direct food preservative in the US.
• Open Food Facts additives taxonomy node en:e284
  Cross-check: OFF maps E284 to the same 2013 EFSA re-evaluation; it records no exposure-exceedance flags, so this row's higher-concern-for-young-children flag comes from the EFSA table directly, not from OFF.

Why this class

IARC Group 2B; or an EFSA re-evaluation that flagged genotoxicity data gaps, found safety could not be assessed on the available data, or cut the ADI citing child exposure; or an EU harmonised classification of the substance as a reproductive or developmental hazard; or an EU withdrawal of one authorised food use while others remain; or an OEHHA/Proposition 65 listing; or membership of the Southampton-six colourants.

Our confidence in this row's classification is medium. Medium or low does not mean the evidence is weak; it means something about the row is still being pinned down, usually a regulatory status confirmed from one source rather than two.

Questions parents ask

Is Boric acid (E284) safe for kids?

Moderate risk. In Sito it takes 15 points off the additive subscore, a third of a product's score (about 5 of the 100). It is flagged for young children, so for a child under 6 it moves up one class, to high risk: 30 points off the additive subscore. The finding we rely on: Group ADI 0.16 mg boron/kg bw/day established (NOAEL 9.6 mg boron/kg bw/day from a rat developmental study, uncertainty factor 60); male reproductive system adversely affected in rats, mice and dogs; boric acid and sodium tetraborate do not raise concern for genotoxicity. Exposure from the additive use at the highest mean: children 0.04 mg boron/kg bw/day. At the 95th percentile for consumers only: children 0.56 vs adolescents 0.37, adults 0.13, elderly 0.15, children highest, 3.5x the ADI, the basis of the child flag. The Panel concluded regular exceedance of the ADI is unlikely given the caviar-only authorisation (EFSA, 10.2903/j.efsa.2013.3407 (EFSA Journal 2013;11(10):3407)).

What is E284?

E284 is the E number for Boric acid, a preservative. Open Food Facts tags it en:e284.

Next to it on the label

The E numbers either side of E284 in our table, then the closest preservatives by number.

• Sodium nitrate (E251), high risk, flagged for young children
• Potassium nitrate (E252), high risk, flagged for young children
• Propionic acid (E280), low risk
• Sodium propionate (E281), low risk
• Calcium propionate (E282), low risk
• borax (E285), moderate risk, flagged for young children