Sodium phosphates are three chemical compounds, sodium salts of phosphoric acid. 

They come in the form of crystalline whitish powder.

What they are used for and where

Food

They are included in the list of European food additives as E339 acidity regulators and chelating agents as primary functions, but can also act as raising agents, thickeners, emulsifiers and stabilisers.

• E339 (i) Monosodium phosphate   CAS   7558-80-7
• E339 (ii) Disodium phosphate   CAS    7558-79-4
• E339 (iii) Trisodium phosphate   CAS   7601-54-9

Safety

The Panel on Food Additives and Flavourings added to Food (FAF) provided a scientific opinion re-evaluating the safety of phosphates (E 338–341, E 343, E 450–452) as food additives. The Panel considered that (1). The Panel considered that phosphates have low acute oral toxicity and there is no concern regarding genotoxicity and carcinogenicity. The Panel calculated a group Acceptable Daily Intake (ADI) for phosphates expressed as phosphorus of 40 mg/kg body weight (bw) per day and concluded that this ADI is protective for the human population (1).

Cosmetics

Anti-sebum.  Controls and reduces emissions from the sebaceous glands, which are responsible for greasy, enlarged pores in the skin, where it occurs, particularly on the forehead, cheeks, nose and hair. Adjuvant in the treatment of acne.

Buffering agent. It is an iingredient that can bring an alkaline or acid solution to a certain pH level and prevent it from changing, in practice a pH stabiliser that can effectively resist instability and pH change.

Deodorant agent. When substances that give off an unpleasant odour are included in cosmetic formulations (typical examples are methyl mercaptan and hydrogen sulphide derived from garlic), deodorants attenuate or eliminate the unpleasant exhalation.

Other uses

• Cleaning : degreaser, removes stains
• Water : softener
• Toothpastes : whitener

Sodium phosphates, studies

Monosodium Phosphate

Molecular Formula   H₂NaO₄P   NaH₂PO₄

Molecular Weight  119.976 g/mol

CAS  7601-54-9   13472-35-0 / 7558-80-7 / 7632-05-5 

EC Number   231-449-2 / 231-558-5 

Synonyms:

• Ortofosfato trisodico
• Fosfato di sodio
• diidrogenofosfato di sodio
• disodium hydrogen phosphate
• phosphoric acid, sodium salt
• sodium biphosphate
• sodium dihydrogen orthophosphate
• phosphoric acid, disodium salt, dodecahydrate

References_____________________________________________________________________

(1) EFSA Panel on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Engel KH, Fowler P, Frutos Fernandez MJ, Fürst P, Gürtler R, Husøy T, Mennes W, Moldeus P, Oskarsson A, Shah R, Waalkens-Berendsen I, Wölfle D, Aggett P, Cupisti A, Fortes C, Kuhnle G, Lillegaard IT, Scotter M, Giarola A, Rincon A, Tard A, Gundert-Remy U. 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. EFSA J. 2019 Jun 12;17(6):e05674. doi: 10.2903/j.efsa.2019.5674.