E339III - Trisodium phosphate

At a glance

This quick summary explains what trisodium phosphate does in foods.

• Names: Trisodium phosphate, tribasic sodium phosphate, E339iii
• What it does: pH control (buffer), emulsifier, stabiliser, sequestrant (binds metal ions), thickener, humectant
• Common places: Processed cheese and cheese spreads; allowed as a processing aid on poultry
• Chemistry: Na3PO4; often used as the anhydrous or hydrate forms
• Label check: Look for “trisodium phosphate” or “sodium phosphate”
• Regulatory status: Permitted in the U.S. and EU within good manufacturing practice and overall phosphate limits

Why is Trisodium phosphate added to food?

Manufacturers use it to control acidity (as a buffer), keep proteins and fats mixed (as an emulsifying salt), stabilize texture, and bind metal ions that can cause off-flavors or discoloration. In the EU, phosphates, including E339iii, are authorized for these technological functions, and their overall intake is assessed as a group.¹

What foods contain Trisodium phosphate?

You are most likely to see it in processed cheese and cheese spreads, where phosphate salts act as emulsifying agents to create a smooth, sliceable melt.² In meat and poultry plants, trisodium phosphate is also listed by the U.S. Department of Agriculture as safe and suitable for certain antimicrobial processing uses on carcasses and parts, which can reduce surface bacteria; as a processing aid it does not remain in significant amounts in the final prepared product.³

What can replace Trisodium phosphate?

Substitutes depend on the job it performs:

• For emulsifying in processed cheese: other phosphates such as sodium phosphates, diphosphates, or polyphosphates are commonly used.
• For buffering and tartness: citric acid or sodium citrates are typical alternatives.
• For general pH adjustment: sodium carbonates can help, depending on the recipe.
• For stabilizing texture: hydrocolloids such as carrageenan or lecithins may be options.

How is Trisodium phosphate made?

Food-grade trisodium phosphate is produced by neutralizing food-grade phosphoric acid with sodium hydroxide or sodium carbonate, then crystallizing and drying to achieve the anhydrous or hydrated forms that meet identity and purity specifications in the EU.⁴

Is Trisodium phosphate safe to eat?

In the United States, sodium phosphate, tribasic is affirmed by the Food and Drug Administration (FDA) as Generally Recognized As Safe (GRAS) when used in accordance with good manufacturing practice.⁵ In Europe, the European Food Safety Authority (EFSA) evaluated phosphates as a group and set an acceptable daily intake (ADI) of 40 mg phosphorus per kg body weight per day from all phosphate additives; typical use of trisodium phosphate in foods contributes only a portion of this total.¹

Does Trisodium phosphate have any benefits?

From a food-technology standpoint, it helps processed cheese melt smoothly and stay uniform instead of separating.² In meat and poultry plants, approved uses of trisodium phosphate as an antimicrobial processing aid can help reduce surface bacteria on poultry, supporting food safety programs.³

Who should avoid Trisodium phosphate?

People who must limit phosphorus—such as individuals with chronic kidney disease—are often advised to watch for phosphate additives in general, because they are readily absorbed and can raise phosphorus intake.⁶ If you follow a low-sodium diet, remember that phosphate additives containing sodium also contribute to total sodium on the label; choosing lower-sodium options can help manage overall intake.

Myths & facts

• “It’s a heavy-duty cleaner, so it can’t be safe in food.” Food-grade trisodium phosphate is highly purified and used in very small amounts that are regulated; FDA affirms it as GRAS under good manufacturing practice.⁵
• “It’s only a preservative.” It can help preserve quality, but its main roles are pH control, emulsifying, and stabilising texture.¹
• “It always stays in meat or poultry.” When used as an approved processing aid on poultry, it is applied and then rinsed per regulations, so it is not intended to remain at significant levels in the finished product.³

Trisodium phosphate in branded foods

You’ll usually find it listed as “trisodium phosphate” or “sodium phosphate.” It most often appears in:

• Processed cheese slices and spreads
• Some cheese-containing sauces and ready meals
• Poultry processed with antimicrobial dips or sprays at the plant (processing aid; may not appear on retail labels)

To check your own products, read the ingredient list and look for “phosphate” terms, or contact the manufacturer for details about processing aids.

References

Footnotes

1. Re-evaluation of phosphates (E 338–341, E 343, E 450–452) as food additives — EFSA Journal (2019). https://www.efsa.europa.eu/en/efsajournal/pub/5674 ↩ ↩² ↩³

2. Pasteurized process cheese food; identity — 21 CFR 133.169. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-133/section-133.169 ↩ ↩²

3. Safe and Suitable Ingredients Used in the Production of Meat, Poultry, and Egg Products — USDA FSIS Directive 7120.1. https://www.fsis.usda.gov/policy/fsis-directives/7120.1 ↩ ↩² ↩³

4. Commission Regulation (EU) No 231/2012 (additive specifications, including E339) — EUR-Lex. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩

5. Sodium phosphate, tribasic; affirmed as GRAS — 21 CFR 182.1778. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-182/subpart-B/section-182.1778 ↩ ↩²

6. Phosphorus Fact Sheet for Health Professionals — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Phosphorus-HealthProfessional/ ↩