E230 - Biphenyl

At a glance

• What it is: a hydrocarbon made of two benzene rings; also called diphenyl
• What it does: helps prevent mold growth on citrus peels during shipping
• Where it shows up: imported oranges, lemons, and other citrus sold as whole fruit
• Label names: E230, biphenyl, diphenyl
• Typical exposure: very low if you discard the peel; it is not common in processed foods

Why is Biphenyl added to food?

Biphenyl is used as a fungistat—a substance that slows mold growth—on the surface of citrus fruits. It helps fruit arrive at markets in good condition after long transport and storage. In the U.S., the Food and Drug Administration (FDA) lists biphenyl as Generally Recognized as Safe (GRAS) for use as a fungistat in citrus fruit packaging materials when used under good manufacturing practice.¹ EFSA (the European Food Safety Authority) has also evaluated biphenyl in the context of citrus surface treatments.²

What foods contain Biphenyl?

You would most likely encounter biphenyl on whole citrus fruits such as oranges, lemons, limes, and grapefruits treated after harvest to prevent mold. Residues, when present, are largely confined to the peel; the edible pulp contains much lower levels.² It is not typically used in beverages, bakery goods, or other processed foods.²

Related citrus preservatives include orthophenyl phenol (E231) and sodium orthophenyl phenol, which have served similar roles as surface treatments for fruit.²

What can replace Biphenyl?

Several approaches can substitute for biphenyl, depending on the product and logistics:

• Other preservatives: sorbic acid, potassium sorbate, and sodium benzoate are widely used preservatives in many foods (though not always for citrus surface treatment).
• Physical methods: good temperature control, lower humidity, and improved airflow limit mold growth during storage.
• Coatings: fruit waxes such as carnauba wax or shellac can help reduce moisture loss and spoilage; these are not fungistats on their own but may be part of a broader post-harvest program.

How is Biphenyl made?

Biphenyl is a basic petrochemical. Industrially, it is produced from benzene feedstocks by processes that couple two benzene rings to form the C12H10 structure. It may also appear as a byproduct in certain petroleum and coke-oven operations.³

Is Biphenyl safe to eat?

Regulators have assessed biphenyl’s use as a post‑harvest citrus preservative. In the U.S., its use as a fungistat in citrus fruit packaging materials is permitted under GRAS status when applied according to good manufacturing practice, which includes controls that limit consumer exposure.¹ EFSA’s review notes that residues from surface treatments largely remain in the peel, meaning exposure from eating the flesh of citrus is low.² International expert committees (JECFA, a joint FAO/WHO body) have also evaluated biphenyl in this context.⁴

As with any surface treatment, washing and peeling reduce potential intake. If you plan to use zest or peel in recipes, look for fruit labeled as untreated or intended for culinary peel use, or remove waxes and surface residues before using the peel.²

Does Biphenyl have any benefits?

Yes. The main benefit is reduced food waste: by holding mold in check, biphenyl helps more citrus arrive fresh after long shipping and storage. This can improve availability outside harvest seasons and extend market life.²

Who should avoid Biphenyl?

• People who regularly eat citrus peel (zest, candied peel, marmalades using peel): Choose untreated fruit or remove surface residues thoroughly before use.²
• Anyone advised by a healthcare professional to limit exposure to certain post‑harvest treatments should follow that guidance.
• If you have concerns, select organic or explicitly “untreated” citrus, or verify post‑harvest handling with your grocer.

Note: Biphenyl (E230) is not the same as polychlorinated biphenyls (PCBs). PCBs are chlorinated industrial chemicals with very different properties and uses.

Myths & facts

• Myth: “Biphenyl soaks into the fruit, so peeling doesn’t help.” Fact: Residues from surface treatments are mainly in the peel; the pulp has much lower levels.²

• Myth: “Biphenyl is a flavoring.” Fact: It is used as a surface preservative (fungistat), not for flavor.¹

• Myth: “Biphenyl is the same as PCBs.” Fact: Biphenyl is an unchlorinated hydrocarbon; PCBs are chlorinated derivatives with different regulatory status and health profiles.

Biphenyl in branded foods

You will rarely see “E230,” “biphenyl,” or “diphenyl” on ingredient lists because it is applied to whole fruit surfaces rather than mixed into recipes. If used, it may be noted on produce stickers, box labels, or retailer signage for imported citrus. For peels destined for culinary use, check for “untreated” or ask your retailer how the fruit was handled.

References

Footnotes

1. Food Additive Status List — FDA. https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩ ↩² ↩³

2. Re‑evaluation of diphenyl (E 230), 2‑phenylphenol (E 231) and sodium 2‑phenylphenate (E 232) — EFSA Journal 2012;10(4):2634. https://www.efsa.europa.eu/en/efsajournal/pub/2634 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

3. Biphenyl — PubChem (NIH). https://pubchem.ncbi.nlm.nih.gov/compound/7237 ↩

4. Biphenyl and diphenyl oxide — WHO/FAO JECFA Monograph. http://www.inchem.org/documents/jecfa/jecmono/v05je21.htm ↩