Sodium Tetraborate (Borax) E285
antimicrobial — Primarily mineral.
Sodium tetraborate decahydrate
CAS: 1303-96-4
Factual Regulatory Reference
This database provides factual regulatory information compiled from official government sources. It does not constitute medical, nutritional, or safety advice. Regulatory status varies by country and is subject to change. Always refer to your local regulatory authority for the most current information.
What Is Sodium Tetraborate (Borax)?
Sodium tetraborate (borax) is the sodium salt form of boron, authorized in the EU only for use in caviar as a preservative (maximum 4 g/kg as boric acid). Like boric acid (E284), it functions by inhibiting microbial growth but raises concerns about kidney toxicity and reproductive effects at higher exposures. EFSA's 2013 review established a TDI of 0.16 mg/kg body weight for boron compounds. Many countries prohibit its use in food entirely, and in the EU its application is strictly limited to caviar only.
? Did You Know?
Sodium Tetraborate (Borax) occurs naturally in Dried lake beds and Mineral deposits. Many people consume it daily without realizing it's also a listed food additive.
Beyond food, Sodium Tetraborate (Borax) is also used in cosmetics, medicine, industrial applications, household products. Its versatility makes it one of the most multi-purpose chemical compounds in everyday life.
Regulatory Analysis
Sodium tetraborate (borax, E285) and boric acid (E284) are regulated as part of the same boron compounds group by EFSA, sharing a single TDI of 0.16 mg/kg body weight established in 2013. Unlike E284, E285 is prohibited even in the EU for food use — only boric acid carries the caviar exemption. The regulatory significance of E285 lies partly in its historical context: borax was widely used in early 20th-century food preservation until animal toxicity data prompted global bans. Its continued illegal use in some imported Asian food products — noted by multiple food safety agencies — has kept it under active enforcement surveillance. No jurisdiction has found the benefit-risk calculation to favor food authorization, making E285 a case where regulatory convergence arose from consistent toxicological findings.
Detailed Regulatory Assessment
European Union (EFSA)
Not authorized for use in foods
United States (FDA)
Not approved for use in food
Japan (MHLW)
Not permitted in food
Acceptable Daily Intake (ADI)
International Standard (JECFA)
mg/kg body weight per day
European Standard (EFSA)
Everyday Perspective
For a 60kg adult, this limit is roughly equivalent to consuming:
Natural Occurrence
A naturally occurring mineral salt with antimicrobial properties. Historically used as a food preservative but now banned in most countries due to toxicity concerns.
Manufacturing
Mined from natural deposits and purified, or synthesized from boric acid and sodium carbonate.
Applications Beyond Food
Restricted or banned in many regions
Historically used but now restricted
Cleaning agent, flux for soldering, fire retardant
Laundry booster, cleaning agent, slime-making (craft use)