Potassium Phosphate E340


  • What is potassium phosphate E340?

Potassium phosphate (E340) is a food allergen that that belongs to the class of acidifying, sequestering, stabilizing, leavening, buffering, and neutralizing substances. It is an inorganic antioxidant by nature.

 In what forms does potassium phosphate appear?

Potassium phosphate appears in 3 forms:

  • E 340 (I) – Monopotassium phosphate;
  • E 340 (II) – Dipotassium phosphate;
  • E 340 (III) – Tripotassium phosphate.
  • Additive E 340 I has the following synonyms: monopotassium phosphate, monopotassium monophosphate, acid potassium phosphate, potassium dihydrogen phosphate, or potassium dihydrogen monophosphate. Its chemical name is potassium dihydrogen phosphate, potassium dihydrogen orthophosphate, or potassium dihydrogen monophosphate. The molecular formula is KH2PO4, and its molar mass, M, is 136.09 g/mol.

Industrially, it is obtained by mixing an appropriate quantity of phosphoric acid with a solution of potassium hydroxide or potassium carbonate.[1]

It is found in the form of colorless, tetragonal crystals, crystalline powder, or white granules. It is an odorless and hygroscopic substance.

It is easily soluble in water (33g per 100 ml of water at 25°C) with hydrolysis but is insoluble in ethanol.

The melting point is 253°C, and the pH of a 1% aqueous solution ranges from 4.2 to 4.8. It is stable in the presence of air, but when heated to 400°C, it first transforms into pyrophosphate and then into metaphosphate.1 , [2]


Additive E 340 II has the following synonyms: dipotassium monophosphate, secondary potassium phosphate, dipotassium acid phosphate, dipotassium orthophosphate, or dibasic potassium phosphate. Its chemical name is dipotassium hydrogen monophosphate, dipotassium hydrogen phosphate, or dipotassium hydrogen orthophosphate.

Its chemical formula is K2HPO4, and the molecular mass is M = 174.18 g/mol.

Industrially, it is obtained by treating phosphoric acid with potassium carbonate or potassium hydroxide. Dipotassium orthophosphate is found in the form of white crystals or colorless paste, as well as white crystals or white powder.

It is a highly hygroscopic substance, even deliquescent (it absorbs water vapor from the air to form a solution).

It is soluble in water (89g/100ml of water), and the pH of a 1% aqueous solution ranges from 8.7 to 9.4.

It is insoluble in ethanol, and upon calcination, it transforms into pyrophosphate.

The food additive must contain no less than 98% of the active substance after drying at 105°C for four hours, with dehydration losses not exceeding 2%.[3]

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  • Additive E 340 III has the following synonyms: tripotassium phosphate, orthophosphate tripotassium. Its chemical name is monopotassium tripotassium phosphate, tripotassium phosphate, or orthophosphate tripotassium. It is found in an anhydrous state as K3PO4 with a molecular mass of M = 212.27 or hydrated with n molecules of water as K3PO4.nH2O, where n can be 1 or 3..

It is industrially obtained by treating phosphoric acid with an excess of potassium hydroxide.

It is in the form of colorless or white crystals or granules, odorless, and hygroscopic. Available hydrate forms include the monohydrate and the trihydrate.

It is soluble in water but insoluble in ethanol. It undergoes strong hydrolysis, resulting in an alkaline solution. The pH of a 1% aqueous solution ranges from 11.5 to 12.3.

It is an odorless, highly hygroscopic, and even deliquescent substance. It should contain a minimum of 97% K3PO4 calculated based on the ignited substance (at 800°C for 30 minutes), and the content of insoluble substances should not exceed 0.2% based on the dried substance. It also contains between 30.5% and 34.0% P2O5 calculated based on the ignited substance. 1, [4], [5]


  • The need for the use of additives E340 (I, II, III)

Additives E340 (I, II, III) are used in food products for their roles as follows:

  • Buffering and Neutralizing Agents: As buffer substances, the mixture in different proportions of monopotassium orthophosphate and dipotassium orthophosphate maintains the constant pH of the environment in which they are incorporated.


  • Sequestrants: They have the role of binding heavy metals in some food products, forming complex combinations (chelates), which inhibit the catalytic action of these elements.


By sequestering metallic ions (copper, iron, lead), they prevent their prooxidant action, thus inhibiting the rancidity reaction of fats (oils, butter, etc.). This extends their storage duration and preserves the aroma of products containing emulsified fats or oils, preventing the development of a rancid taste and odor (in confectionery and pastry products). In butter or margarine, their original aroma is also preserved.

  • Antioxidants: Additives E340 play a synergistic role when used together with antioxidants such as BHA, BHT, propyl gallate, ascorbic acid, and isoascorbic acid.
  • Stabilizers, etc.


In some food products, dipotassium and tripotassium orthophosphates act as neutralizers of their acidity (they have a basic pH). Additives E340 also solubilize, emulsify, and stabilize proteins, especially when making processed cheeses.


  • Which foods contain food additives E340 (I, II, III)? Maximum permissible usage limits.


The current legislation provides for the use of food additives E340 (I, II, III) either separately or in combination with E339 (I, II, III), E341 (I, II, III), E343, E450, E451, and E452 in the following food products, with the maximum permissible usage limits:în băuturi aromate nealcoolice în doza de 700mg/l;

  • In non-alcoholic flavored beverages at a dose of 700mg/l.;
  • In energy drinks and prepared water at 0.5g/l.
  • In vegetable protein beverages at 20g/l.
  • In alcoholic beverages (excluding wine and beer) at 1g/l.
  • In coffee-based drinks for automatic machines at 2g/l.
  • In UHT milk at 1g/l.
  • In partially desiccated milk with up to 28% solids content at 1g/l.
  • In partially desiccated milk with more than 28% solids content at 1.5g/l.
  • In skimmed milk powder at 2.5 g/kg.
  • In pasteurized, sterilized (UHT) cream at 5g/kg.
  • In cream and vegetable fats at 5g/kg.
  • In melted cheese and similar products with melted cheese at 20g/kg.
  • In fresh cheese (excluding Mozzarella) at 2g/kg.
  • In chocolate and malt-based milk beverages at 2g/l.
  • In butter and sour cream preparations at 2g/kg.
  • In meat products, it is used in doses of 5g/kg.
  • In unprocessed, refrigerated or frozen fish fillets at 5g/kg.
  • In unprocessed or processed mollusks and crustaceans, refrigerated or frozen, at 5g/kg.
  • In canned crustacean products at 1g/kg.
  • In fish and crustacean paste and spreadable fatty products (excluding butter) in cans at 5g/kg.
  • In confectionery products at 5g/kg, in sugar for icing at 10g/kg, in flavored syrups for ice creams and similar products at 3g/kg.
  • In chewing gum “qs,” mixtures and dessert powders at 7g/kg, in desserts at 3g/kg, in candied fruits and fruit preparations at 800mg/kg.
  • In processed and prepared potatoes, refrigerated, or frozen at 5g/kg.
  • In snacks at 1.5g/kg.
  • In liquid eggs at 10g/kg.
  • In tea and herbal infusion at 2g/kg.
  • In cider and pear brandy at 2g/l.
  • They can also be added to dietary supplements “qs,” in salt and its substitutes at 10g/kg.
  • In cleaning agents for installations at 30g/kg or in dispensers at 50g/kg.
  • In food ice at 1g/kg.
  • In bakery and pastry products, the additives are used for fine pastry products at 20g/kg.
  • In flour at 2,5 g/kg.
  • In flour with leavening agents at 20g/kg.
  • In dough at 5g/kg.
  • In pasta at 2g/kg, as well as in aqueous emulsions for pastry molds.
  • In sauces at 5 g/kg
  • In soups and broths at 3g/kg
  • In chewing gum „qs”
  • In powdered food products at 10g/kg.
  • In breakfast cereals at 5g/kg.
  • In snacks at 5g/kg [6]
  • In special dietary foods for infants, for special medical purposes, and special formulas for infants at 100mg/kg.
  • In processed grain-based foods and foods for young children, the maximum level of phosphates when used as food additives, other than supporting substances, in food additives is 40,000 mg/kg individually or in combination in the preparation (expressed as P2O5) and can be used in coloring preparations.
  • In food additives, including supporting substances, in food enzymes, the maximum level at which potassium phosphates can be added in enzymatic preparation is 50,000 mg/kg (individually or in combination, expressed as P2O5).[7]


  • Are there any side effects associated with the consumption of food additives E340?


Phosphates represent essential constituents of the human body; therefore, it is necessary for the consumed foods to contain these substances. The phosphate content in the blood remains constant due to the continuous exchange with the mineral substances of the skeleton. This exchange is regulated by the parathyroid hormone. The calcium ion in the blood plays an important role as it regulates the amount of hormone that enters the bloodstream. Some experiments conducted on rats have demonstrated that when the diet has a high phosphate content, they suffer from parathyroid hypertrophy, kidney stones, and aortic calcifications.


Other experiments have shown that excessive phosphate consumption can hinder the assimilation of other mineral substances (in the long term, it can disrupt the natural balance of calcium and phosphorus in the body). It has also been observed that higher consumption can lead to hyperactivity and digestive problems. 1, [8]


The toxicity of phosphates was first assessed by the Scientific Committee of the EU for Food, and then by JECFA (the Joint FAO/WHO Expert Committee on Food Additives), which regulates the use of food additives. It concluded that establishing a daily acceptable intake (DAI) of 30 mg/kg body weight was not suitable for phosphates “because phosphorus is an essential nutrient and an unavoidable component of food.” Therefore, it was decided to establish a “maximum tolerable daily intake” (MTDI) rather than a DAI.

The MTDI established was 70 mg/kg body weight/day (expressed as phosphorus) for the mixture of phosphates and polyphosphates, both naturally present in foods and ingested as food additives.[9] [10]


  • Conclusions and Legislative Regulations – E340


Potassium phosphates are regulated at the European level by Regulation (EU) No 1129/2011, and at the national level, there is a standard (dated July 12, 2002) regarding food additives intended for use in food products for human consumption. This standard sets maximum permitted limits for each category of food product where they can be used.6


Additives E340 (I, II, III), potassium phosphates, can be found in many food products, which is why it is essential to carefully account for the amount of phosphorus ingested throughout the day to avoid exceeding the recommended dose.



[1] Elena Olanescu, Aditivii alimentari-necesitate și risc, Editura SemnE, 2005, Bucuresți, pag. 164-168;

[2] https://www.fao.org/fileadmin/user_upload/jecfa_additives/docs/Monograph1/Additive-336.pdf

[3] https://www.fao.org/fileadmin/user_upload/jecfa_additives/docs/Monograph1/Additive-162.pdf

[4] Regulamentul (UE) nr. 231/2012 al Comisiei din 9 martie 2012 de stabilire a specificațiilor pentru aditivii alimentari enumerați în anexele II și III la Regulamentul (CE) nr. 1333/2008 al Parlamentului European și al Consiliului Text cu relevanță pentru SEE, EUR-Lex – 32012R0231 – EN – EUR-Lex (europa.eu) (EUR-Lex – 32012R0231 – EN – EUR-Lex (europa.eu),

[5] https://www.fao.org/fileadmin/user_upload/jecfa_additives/docs/Monograph1/Additive-480.pdf

[6]  NORMĂ din 12 iulie 2002 privind aditivii alimentari destinați utilizării în produsele alimentare pentru consum uman) Publicat în  Monitorul Oficial nr. 722 bis din 3 octombrie 2002

[7] https://eur-lex.europa.eu/legal-content/RO/TXT/PDF/?uri=CELEX:02008R1333-20160525&from=FR

[8] https://www.scridoc.com/2020/02/e340-fosfati-de-potasiu-in-ce-alimente_74.html

[9]  Re-evaluation of food additives: call for data (15.2.2012). E 340 Potassium phosphates. Submitted to EFSA on August 2012.

[10] Re-evaluation of phosphoric acid–phosphates – di-, tri- and polyphosphates (E 338–341, E 343, E 450–452) as food additives and the safety of proposed extension of use, https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2019.5674.

Translated from Romanian by: Andra Nițu

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