E284 - Boric acid

At a glance

• Name: Boric acid (also called boracic or orthoboric acid)
• E‑number: E284
• Former role: Preservative, especially in certain fish roe products like caviar
• Current status: Not widely permitted as a food additive; check your local rules
• Taste/impact: Minimal flavor at low levels; used for antimicrobial effect rather than taste
• Typical replacements: Salt and cold storage; approved preservatives such as sorbic acid, potassium sorbate, and sodium benzoate
• Label names: “Boric acid,” “boracic acid,” or “E284”

Why is boric acid added to food?

Boric acid was historically used to slow spoilage by inhibiting the growth of bacteria, yeasts, and molds, especially in delicate foods such as caviar and other fish roe products. Its role was preservation rather than flavoring or nutrition.¹

In modern regulations, only additives specifically authorized can be used in foods; boric acid is not on the European Union’s Union list of permitted food additives, so it is not authorized for use as a food additive in the EU.²

What foods contain boric acid?

Historically, the best known use was in preserved sturgeon caviar and other fish roe where low-temperature storage and added preservatives helped extend shelf life.¹ Today, in jurisdictions where it is not authorized as a food additive (such as the European Union), properly labeled retail foods should not list boric acid (E284) as an ingredient.²

What can replace boric acid?

Producers typically use a combination of cold chain management, salt, hygienic processing, and permitted preservatives. Common preservative alternatives include:

• Sorbic acid and potassium sorbate for mold and yeast control²
• Sodium benzoate in suitable product categories²
• pH control with acids such as citric acid where appropriate²

Always check local regulations because permitted additives and use levels vary by food category and country.²

How is boric acid made?

Industrial boric acid is typically produced from borate minerals (such as borax) by reacting them with strong acids or with carbon dioxide under controlled conditions. These processes convert sodium borates into purified boric acid crystals for industrial applications.³

Is boric acid safe to eat?

Boric acid is not generally used as a food ingredient today because its safety margin for oral exposure is limited, especially when considering total dietary boron intake from all sources.¹ In the European Union, only additives on the Union list may be used; boric acid (E284) is not listed and therefore is not authorized as a food additive.²

Symptoms reported after excessive oral exposure include nausea, vomiting, diarrhea, and, in severe cases, effects on the kidneys and other organs.⁴ Risk assessments for boron (the element in boric acid) have proposed conservative tolerable intakes, reflecting the need to limit exposure from all sources.¹

Does boric acid have any benefits?

Boric acid does not provide nutritional value. Boron, the element in boric acid, is not recognized as an essential nutrient for humans, and there is no Recommended Dietary Allowance (RDA). Some research explores possible roles of boron in bone and mineral metabolism, but evidence is not sufficient to establish essentiality; public-health guidance focuses instead on staying below safe upper intake levels.⁵

Who should avoid boric acid?

• Pregnant or breastfeeding individuals should avoid unnecessary exposure to boron compounds because safety margins are narrow and conservative upper intake levels apply.⁵
• Infants and young children are more vulnerable to excessive exposures, so boron-containing preservatives are inappropriate in their foods.⁴
• People with kidney problems should be especially cautious, since the kidneys help clear boron from the body and reduced function could increase susceptibility to adverse effects.⁴

Myths & facts

• “It’s natural, so it’s safe.” Natural origin does not guarantee safety. Many naturally occurring substances are not suitable as food additives at meaningful doses.⁴
• “It was used in the past, so it’s fine to use now.” Regulatory standards evolve with new evidence. In the EU, boric acid (E284) is not authorized as a food additive under current rules.²
• “Boric acid and borax are the same thing.” They are closely related boron compounds, but not identical; both were historically considered for preservation, and both have been reevaluated for safety.¹

Boric acid in branded foods

You are unlikely to see E284 on ingredient lists in regions where it is not authorized, such as the European Union.² If present in markets that allow it, look for “boric acid,” “boracic acid,” or “E284” on the label and verify local regulations before purchase.

References

Footnotes

1. Scientific Opinion on the re-evaluation of boric acid (E 284) and sodium tetraborate (E 285) as food additives — European Food Safety Authority (EFSA). https://www.efsa.europa.eu/en/efsajournal/pub/3407 ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Commission Regulation (EU) No 1129/2011 establishing a Union list of food additives — European Union (EUR-Lex). https://eur-lex.europa.eu/eli/reg/2011/1129/oj ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

3. Mineral Commodity Summaries: Boron — U.S. Geological Survey (USGS). https://pubs.usgs.gov/periodicals/mcs2023/mcs2023-boron.pdf ↩

4. Toxicological Profile for Boron — Agency for Toxic Substances and Disease Registry (ATSDR), U.S. Department of Health and Human Services. https://www.atsdr.cdc.gov/ToxProfiles/tp26.pdf ↩ ↩² ↩³ ↩⁴

5. Boron Fact Sheet for Health Professionals — National Institutes of Health, Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Boron-HealthProfessional/ ↩ ↩²