E231 - Orthophenyl phenol

At a glance

• What it is: a man‑made preservative (also called 2‑hydroxybiphenyl)
• What it does: fights mold and bacteria, especially on surfaces
• Where it shows up: niche uses such as certain food‑contact materials; direct use in foods is restricted and regulated
• Safety: regulated with identity and purity limits; permitted only in specific uses and amounts set by law

Why is Orthophenyl phenol added to food?

Manufacturers use Orthophenyl phenol (OPP) as an antimicrobial preservative. It works by disrupting microbial cell membranes, which helps prevent spoilage, especially on surfaces where mold can take hold. In the European Union (EU), OPP is listed as E231 and has formal identity and purity specifications, reflecting its status as a tightly controlled additive rather than a broad, everyday ingredient.¹

In practice, OPP is more often seen in specialized roles (for example, in some food‑contact applications) than as something mixed into recipes. Its sodium salt, sometimes used in similar contexts, is regulated separately.¹

What foods contain Orthophenyl phenol?

You are unlikely to find Orthophenyl phenol on a long list of packaged food ingredients. Instead, it shows up in niche, regulated uses where surface protection is important or where the substance functions upstream in the supply chain. In the United States, for example, OPP is permitted as a “slimicide” (an antimicrobial used to control slime‑forming microorganisms) in the manufacture of paper and paperboard intended to contact food, under defined conditions.² That means the compound is controlled in the processing environment rather than added to the food itself.

Regulators in different regions also manage possible residues from antimicrobial or pesticide uses through tolerance systems, which set strict limits on how much may remain on or in foods.³

What can replace Orthophenyl phenol?

Depending on the food and purpose, manufacturers may choose other, widely used preservatives and antioxidants, such as:

• sorbic acid or potassium sorbate for yeast and mold control in many foods
• sodium benzoate for acidic drinks and condiments
• extracts of rosemary as an antioxidant to slow rancidity

The best alternative depends on the food’s pH, moisture, packaging, and desired shelf life.

How is Orthophenyl phenol made?

Orthophenyl phenol is produced synthetically. In the EU, its composition, purity, and allowable impurities are defined in a legally binding specification, which helps ensure a consistent ingredient profile regardless of manufacturer.¹ Chemically, it is the molecule 2‑hydroxybiphenyl, a small aromatic compound composed of two linked benzene rings with a single hydroxy (–OH) group.⁴

Is Orthophenyl phenol safe to eat?

Safety depends on how, where, and how much is used. Two layers of control are common:

• Identity and purity specifications that set what the additive must be (and what it must not contain in excess). In the EU, these are set in a dedicated regulation for food additive specifications.¹
• Use‑specific rules that restrict applications and limit potential consumer exposure (for example, by confining the substance to processing aids in food‑contact materials in the U.S., or by setting residue tolerance systems that cap what can appear on food).²³

When used as permitted, consumer exposure is expected to remain low and within regulatory limits. People concerned about preservatives can minimize exposure by peeling or washing produce where appropriate and by checking product labels.

Does Orthophenyl phenol have any benefits?

Yes. Its main benefit is reducing spoilage from molds and bacteria on surfaces. This can help:

• keep products fresher during transport and storage
• reduce food waste caused by surface mold or quality loss
• support food safety by slowing microbial growth in vulnerable spots

Who should avoid Orthophenyl phenol?

Most people do not need to avoid Orthophenyl phenol when it is used within legal limits. However:

• Individuals who prefer to avoid certain preservatives for personal or dietary reasons can choose products that do not use them.
• Anyone with a known sensitivity to phenolic disinfectants or preservatives should follow their healthcare provider’s advice and check labels.

Myths & facts

• Myth: “If it has an E‑number, it’s unsafe.” Fact: An E‑number means the additive has been evaluated and is regulated for specific uses in the EU.¹
• Myth: “This preservative is always in the food itself.” Fact: Many uses are on surfaces or in processing steps and food‑contact materials, with strict rules to limit consumer exposure.²³

Orthophenyl phenol in branded foods

You are unlikely to see Orthophenyl phenol listed on many everyday ingredient panels. If present, it tends to appear in tightly controlled uses close to the surface of a product or in materials that contact food during processing and packaging. For practical guidance, look for any handling statements on fresh produce, follow washing or peeling advice on labels, and contact the manufacturer if you need details about preservatives used in coatings or packaging.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — Laying down specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³ ↩⁴ ↩⁵

2. 21 CFR 176.300 — Slimicides used in the manufacture of paper and paperboard in contact with food. U.S. eCFR. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-176/section-176.300 ↩ ↩² ↩³

3. 40 CFR Part 180 — Tolerances and exemptions for pesticide chemical residues in food. U.S. eCFR. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-E/part-180 ↩ ↩² ↩³

4. 2-Phenylphenol — PubChem, National Institutes of Health. https://pubchem.ncbi.nlm.nih.gov/compound/2-Phenylphenol ↩