E343I - Monomagnesium phosphate

At a glance

• Other names: magnesium dihydrogen phosphate, monobasic magnesium phosphate, E343i
• What it does: stabiliser and thickener; also acts as a pH buffer within the phosphate family
• Typical uses: powdered mixes, dairy-style products, processed cheese systems and sauces, and other foods where texture and pH control matter
• Dietary notes: inorganic, vegan- and vegetarian-friendly, gluten-free
• Heat and storage: generally heat-stable and effective over common food-processing conditions

Why is Monomagnesium phosphate added to food?

Food makers use monomagnesium phosphate to steady texture and control acidity. In recipes, it helps proteins and water stay evenly mixed, keeps emulsions from breaking, and provides mild buffering so pH does not swing too much during processing or storage. These functions are typical for phosphates used as stabilisers and acidity regulators in many foods.¹

What foods contain Monomagnesium phosphate?

In the European Union, phosphates as a group (including E343) are authorised in a wide range of food categories under specific conditions. Examples include some processed cheeses, dairy analogues, powdered soups and beverages, bakery mixes, and certain meat and fish products where stabilisation, emulsification, or pH control are needed.² Actual use depends on the recipe and local rules, so the best way to know is to check the ingredient list for “monomagnesium phosphate” or “E343”.

What can replace Monomagnesium phosphate?

Possible alternatives depend on the job it performs in your product:

• For pH control and buffering: sodium phosphates, potassium phosphates, or organic acids such as citric acid and its salts like sodium citrates
• For stabilising proteins and emulsions in processed cheese and sauces: monocalcium phosphate, diphosphates, triphosphates, or polyphosphates
• For thickening and texture: hydrocolloids such as carrageenan, xanthan gum, or pectins

How is Monomagnesium phosphate made?

Food‑grade monomagnesium phosphate is produced by carefully neutralising purified phosphoric acid with a magnesium source (for example magnesium oxide, hydroxide, or carbonate), followed by crystallisation, drying, and milling. Its identity and purity must meet the specifications laid out in EU rules for food additives (including limits for impurities and defined assay ranges).³

Is Monomagnesium phosphate safe to eat?

The European Food Safety Authority (EFSA) re‑evaluated phosphate additives and set a group acceptable daily intake (ADI) of 40 mg/kg body weight per day, expressed as phosphorus, for phosphoric acid and its salts, including E343. EFSA also noted that total dietary exposure to phosphates can be high in some groups, such as children with high consumption of phosphate-containing foods, and recommended managing overall intake.¹ As with all phosphates, safety depends on total phosphorus from both naturally occurring foods and additives in the diet.¹

Does Monomagnesium phosphate have any benefits?

This additive can contribute small amounts of magnesium and phosphorus, both essential nutrients. Magnesium supports normal muscle and nerve function and many enzyme reactions,⁴ while phosphorus is a key part of bones, teeth, and energy metabolism.⁵ However, monomagnesium phosphate is added for its technological effects, not as a major nutrient source, so the amounts present in foods are usually modest.

Who should avoid Monomagnesium phosphate?

• People with chronic kidney disease or those advised to follow a low‑phosphorus diet should monitor total phosphorus intake, including from phosphate additives.⁶
• Individuals with impaired kidney function may also need to limit magnesium to avoid excessive blood levels; consult a healthcare professional.⁴
• Anyone with a known sensitivity to phosphate additives should read labels and choose alternatives as advised by their clinician.

Myths & facts

• Myth: “All phosphate additives are the same.” Fact: There are many phosphate salts (sodium, potassium, calcium, magnesium; simple and condensed forms) and they behave differently in foods.
• Myth: “Phosphates are unnatural.” Fact: Phosphorus naturally occurs in many staple foods; additives are purified, food‑grade salts used to achieve specific functions.⁵
• Myth: “Phosphates always act as leavening agents.” Fact: Some phosphates do, but monomagnesium phosphate is mainly used as a stabiliser, thickener, and pH buffer.

Monomagnesium phosphate in branded foods

On ingredient lists, look for “monomagnesium phosphate,” “magnesium dihydrogen phosphate,” or “E343”. You may see it in processed cheese and cheese‑style spreads, shelf‑stable sauces, powdered beverages and soups, non‑dairy creamers, and certain bakery or meat products that need stable texture and controlled pH. If you are managing phosphorus intake, compare similar products and choose items with fewer phosphate additives.

References

Footnotes

1. Re‑evaluation of phosphoric acid–phosphates–di‑, tri‑ and polyphosphates (E 338–341, E 343, E 450–452) as food additives — European Food Safety Authority. https://www.efsa.europa.eu/en/efsajournal/pub/5674 ↩ ↩² ↩³

2. Regulation (EC) No 1333/2008 on food additives (authorised uses and categories) — EUR-Lex. https://eur-lex.europa.eu/eli/reg/2008/1333/oj ↩

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

4. Magnesium Fact Sheet for Health Professionals — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/ ↩ ↩²

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

6. Chronic Kidney Disease: Eating Right for Kidney Health (phosphorus guidance) — National Institute of Diabetes and Digestive and Kidney Diseases (NIH). https://www.niddk.nih.gov/health-information/kidney-disease/chronic-kidney-disease-ckd/eating-nutrition ↩