Sodium tetraborate (borax) is the preservative the food industry lists as E285. 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).
- The key finding, from EFSA: Boron is the toxicologically active species; group ADI 0.16 mg boron/kg bw/day; children's P95 exposure from additive use 0.56 mg boron/kg bw/day, the highest of any population group; authorised in the EU only as a preservative for sturgeon eggs (caviar) (10.2903/j.efsa.2013.3407)
- Flagged for young children. Set only where EFSA’s own exposure assessment shows toddlers or children exceeding or approaching the ADI, or where a regulator used explicitly child-specific language. For a child under 6 it moves up one class, to high risk.
- Where you meet it. None of the 10,000 packaged foods scanned most on Open Food Facts list it. Nine in ten of those foods are sold in Europe (counted 26 Sep 2026).
- 3 citations from EFSA, the FDA and Open Food Facts, each one below.
What borax 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. borax 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.
See what is in your own cupboard
Scan a packaged food and Sito names the additives in it, then scores the product out of 100 for your child's age.
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
Boron is the toxicologically active species; group ADI 0.16 mg boron/kg bw/day; children's P95 exposure from additive use 0.56 mg boron/kg bw/day, the highest of any population group; authorised in the EU only as a preservative for sturgeon eggs (caviar). -
FDA
eCFR search of 21 CFR — no direct food-additive/GRAS listing for borax or sodium tetraborate (food-contact sections only)
Not an approved food preservative in the US. -
Open Food Facts
additives taxonomy node en:e285
Mapped to the same EFSA 2013 re-evaluation; no OFF exposure-exceedance flags — the child figure comes from the EFSA opinion.
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 borax (E285) 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: Boron is the toxicologically active species; group ADI 0.16 mg boron/kg bw/day; children's P95 exposure from additive use 0.56 mg boron/kg bw/day, the highest of any population group; authorised in the EU only as a preservative for sturgeon eggs (caviar) (EFSA, 10.2903/j.efsa.2013.3407).
What is E285?
E285 is the E number for Sodium tetraborate, a preservative. It is also called borax. Open Food Facts tags it en:e285.
Next to it on the label
The E numbers either side of E285 in our table, then the closest preservatives by number.
- Potassium nitrate (E252), high risk, flagged for young children
- Propionic acid (E280), low risk
- Sodium propionate (E281), low risk
- Calcium propionate (E282), low risk
- Boric acid (E284), moderate risk, flagged for young children
- Carbon dioxide (E290), no risk identified