Sodium hydroxide

E number E524INS 524CAS 1310-73-2

Listed as an acidity regulator by Canada, Codex and the US.

Listed as acidity regulators (CA, US, Codex) · colours (US) · flavour enhancers (US) · flour treatment agents (US) · dough strengtheners (US) · flavouring agents and adjuvants (US) · oxidising and reducing agents (US) · starch-modifying agents (CA) · processing aids (US)
Chemical structure of Sodium hydroxide, from PubChem compound 14798
Structure from PubChem CID 14798 (National Library of Medicine, public domain). A depiction of one compound: where a listing covers a family, or a substance has no single structure, this page shows none.

Sodium hydroxide, or lye, is a strongly alkaline processing aid. It gives pretzels their crust and colour, cures olives, and produces hominy from maize; it is normally neutralised or washed out.

Where it is and isn’t permitted

Status of Sodium hydroxide by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
Australia and New ZealandFood Standards Australia New ZealandPermitted, with conditions

2 food categories

highest permitted level 2,000 mg/L

Show every food category
  • 13.1 Infant formula products — 2,000 mg/LApplies in Australia; New Zealand has not adopted Standard 2.9.1 (infant formula products) and applies its own infant formula standard.
  • 13.5 Food for special medical purposes — GMPNote: Permitted for use as an acidity regulator.
Food Standards Code, Schedule 15, S15—5and 1 further provisionretrieved 2026-10-17
CanadaHealth CanadaPermitted, with conditions

no numerical limit (good manufacturing practice)

10 permitted uses

Show every permitted use
  • In: Frozen crustaceans; Frozen molluscs. Purpose: To facilitate the removal of extraneous matter and to reduce moisture loss during cooking. Limit: To be used in a solution with sodium chloride (salt) and calcium oxide. Residue of sodium hydroxide not to exceed 70 ppm in the food. — Health Canada, List of Permitted Food Additives with Other Purposes of Use (List 8), item S.14
  • In: Calorie-reduced margarine; Margarine. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(a)
  • In: Cocoa products as defined in Volume 4 of the Food Compositional Standards Document. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. If used singly, the amount of sodium hydroxide in neutralizing value, calculated from its weight, not to exceed the neutralizing value of 5% anhydrous potassium carbonate by weight of the cocoa product, calculated on a fat-free basis. If used in any combination with other acidity regulators, the total combined amount of these acidity regulators in neutralizing value, calculated from their respective weight, not to exceed the neutralizing value of 5% anhydrous potassium carbonate by weight of the cocoa product, calculated on a fat-free basis. This total combined amount does not include any of citric acid, phosphoric acid or tartaric acid that may be added up to their respective maximum levels of use set out in this list. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(b)
  • In: Frozen egg-white; Liquid egg-white. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. Amendment notices: NOM/ADM-0012. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(c)
  • In: Gelatin. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(d)
  • In: Ice cream mix; Ice milk mix; (Naming the flavour) partly skimmed milk; Pumping pickle, cover pickle and dry cure used in the curing of preserved meat or preserved meat by-product; (Naming the flavour) skim milk. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. Amendment notices: NOM/ADM-0122. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(e)
  • In: Infant formula. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(f)
  • In: Unstandardized foods. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(g)
  • In: (Naming the variety) whey cheese. Purpose: Acidity regulator. Limit: Good Manufacturing Practice. Amendment notices: M-FAA-25-06. — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10), item S.13(h)
  • In: Starch used in the manufacture of modified starch. Purpose: Starch-modifying agent. Limit: Good Manufacturing Practice. — Health Canada, List of Permitted Starch-Modifying Agents (List 13), item S.5
Health Canadaand 9 further provisionsretrieved 2026-10-17
European UnionEuropean Commission / EFSAPermitted, with conditions

76 food categories

highest permitted level 70,000 mg/l

Show every food category
  • 1.10 Milk-based drinks and similar products intended for young children* — quantum satisquantum satis. only for pH adjustment.
  • 1.3 unflavoured fermented milk products heat-treated after fermentation — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 1.4 flavoured fermented milk products including heat-treated products — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 1.6.3 other creams — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 1.7.1 unripened cheese excluding products falling in category 16Permitted as a member of Group I, Additives. except mozzarella.
  • 1.7.5 processed cheese — several limitsPermitted as a member of Group I, Additives. except E 425 ML = 10000 mg/kg; E 620 to E 625, ML =10000 mg/kg individually or in combination, expressed as glutamic acid;E 626 to E 635, ML = 500 mg/kg individually or in combination, expressedas guanylic acid.
  • 1.7.6 cheese products (excluding products falling in category 16) — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 1.8 Dairy analogues, including beverage whiteners — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 1.9 Edible caseinates — quantum satisquantum satis.
  • 10.2 processed eggs and egg products — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML =10000 mg/kg individually or in combination, expressed as glutamic acid;E 626 to E 635, ML = 500 mg/kg individually or in combination, expressedas guanylic acid.
  • 11.2 Other sugars and syrups — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.1.2 salt substitutes — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.2.2 Seasonings and condiments — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.3 Vinegars and diluted acetic acid (diluted with water to 4-30 % by volume) — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.4 Mustard — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.5 Soups and broths — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.6 Sauces — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.7 Salads and savoury-based sandwich spreads — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.8 Yeast and yeast products — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 12.9 Protein products excluding products covered in category 1 8 — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 13.1.3 Processed cereal-based foods and baby foods as defined by Regulation (EU) No 609/2013 — quantum satisquantum satis. only processed cereal based foods and baby foods, only for pH adjustment.
  • 13.1.5.1 Foods for special medical purposes as defined by Regulation (EU) No 609/2013, intended for infants — quantum satisquantum satis. only for pH adjustment.
  • 13.2 Foods for special medical purposes as defined by Regulation (EU) No 609/2013 (excluding products from food category 13.1.5.) — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 13.3 Total diet replacement for weight control food as defined by Regulation (EU) No 609/2013 — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 14.1.2 Fruit juices as defined by Directive 2001/112/EC and vegetable juicesPermitted as a member of Group I, Additives. only vegetable juices.
  • 14.1.3 Fruit nectars as defined by Directive 2001/112/EC and vegetable nectars and similar productsPermitted as a member of Group I, Additives. only vegetable nectars, E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.1.4 Flavoured_drinksPermitted as a member of Group I, Additives. E 420, E 421, E 953, E 965, E 966 and E 967 may not be used E 968 may not be used except where specifically provided for in this food category.
  • 14.1.5.2 otherPermitted as a member of Group I, Additives. excluding unflavoured leaf tea; including flavoured instant coffee; E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used in drinks.
  • 14.2.3 Cider and perryPermitted as a member of Group I, Additives. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.4 Fruit wine and made winePermitted as a member of Group I, Additives. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.5 MeadPermitted as a member of Group I, Additives. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.6 Spirit drinks as defined in Regulation (EU) 2019/787Permitted as a member of Group I, Additives. except whisky or whiskey; E 420, E421, E 953, E 965, E 966, E 967 and E 968 may not be used except in liqueurs.
  • 14.2.7.1 Aromatised winesPermitted as a member of Group I, Additives. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.7.2 Aromatised wine-based drinksPermitted as a member of Group I, Additives. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.7.3 Aromatised wine-product cocktailsPermitted as a member of Group I, Additives. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.8 Other alcoholic beverages including mixtures of alcoholic beverages with non-alcoholic beverages and other alcoholic beverages based on distilled alcohol with alcoholic strength by volume less than 15 %Permitted as a member of Group I, Additives. E 420, E421, E 953, E 965, E 966, E 967 and E 968 may not be used.
  • 15.1 Potato- cereal- flour- or starch-based snacks — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 15.2 Processed nuts — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 16 Desserts excluding products covered in category 1 3 and 4 — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 17.1 food supplements supplied in a solid form excluding food supplements for infants and young children’,Permitted as a member of Group I, Additives. E 410, E 412, E 415, E 417 and E 425 may not be used to produce dehydrated food supplements intended to rehydrate on ingestion.
  • 17.2 food supplements supplied in a liquid form excluding food supplements for Infants and young children — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 18 Processed foods not covered by categories 1 to 17 — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 18.1 Processed foods not covered by categories 18.2 and 18.3, excluding foods for infants and young children — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 18.2 Meal replacement for weight control as referred to in Commission Regulation (EU) No 432/2012 — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 18.3 Food specially produced to reduce the gluten content of gluten-containing ingredients or substitute the gluten-containing ingredientsPermitted as a member of Group I, Additives. Including dry pasta.
  • 2.2.2 Other fat and oil emulsions including spreads as defined by Regulation (EC) No 1234/2007 and liquid emulsions — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 2.3 Vegetable oil pan spray — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 3 edible ices — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 4.2.1 dried fruit and vegetablesPermitted as a member of Group I, Additives. E 410, E 412, E 415 and E 417 may not be used to produce dehydrated foods intended to rehydrate on ingestion.
  • 4.2.2 fruit and vegetables in vinegar oil or brine — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 4.2.4.1 fruit and vegetable preparations excluding compote — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 4.2.5 jam jellies and marmalades and similar products — quantum satisquantum satis.
  • 4.2.5.2 Jam, jellies and marmalades and sweetened chestnut puree as defined by Directive 2001/113/EC — quantum satisquantum satis.
  • 4.2.5.3 other similar fruit or vegetable spreads — quantum satisquantum satis.
  • 4.2.5.4 nut butters and nut spreads — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 4.2.6 processed potato products — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 5.1 Cocoa and chocolate products as covered by Directive 2000/36/ECPermitted as a member of Group I, Additives. only energy-reduced or with no added sugars.
  • 5.1 Cocoa and chocolate products as covered by Directive 2000/36/EC — 70,000 mg/kgPermitted as a member of Hydroxides. ML = 70000 mg/kg. E 170, E 500 - 504, E 524 - 528 and E 530: 7 % on dry matter, without fat, expressed as potassium carbonates.
  • 5.2 Other confectionery including breath freshening micro-sweetsPermitted as a member of Group I, Additives. The substances listed under numbers E 400, E 401, E 402, E 403, E 404, E 406, E 407, 407a, E 410, E 412, E 413, E 414, E 415, E 417, E 418, E 425 and E 440 may not be used in jelly mini-cups, defined, for the purpose of this Regulation, as jelly confectionery of a firm consistence, contained in semi rigid mini-cups or mini-capsules, intended to be ingested in a single bite by exerting pressure on the mini-cups or mini-capsule to project the confectionery into the mouth; E 410, E 412, E 415 E 417 may not be used to produce dehydrated foods intended to rehydrate on ingestion. E425 may not be used in jelly confectionery.
  • 5.3 chewing gum — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 5.4 Decorations, coatings and fillings, except fruit-based fillings covered by category 4.2.4 — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 6.2.2 starches — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 6.3 breakfast cereals — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 6.4.2 Dry pasta — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 6.4.4 Potato GnocchiPermitted as a member of Group I, Additives. except fresh refrigerated potato gnocchi.
  • 6.4.5 fillings of stuffed pasta (ravioli and similar) — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 6.5 Noodles — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 6.6 Batters — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 6.7 pre-cooked or processed cereals — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 7.1 Bread and rollsPermitted as a member of Group I, Additives. except products in 7.1.1 and 7.1.2.
  • 7.2 Fine bakery wares — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 8.3.1 Non-heat-treated processed meat — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 8.3.2 Heat-treated meat productsPermitted as a member of Group I, Additives. except foie gras, foie gras entier, blocs de foie gras, Libamáj, libamáj egészben, libamáj tömbben.
  • 8.3.3 Casings and coatings and decorations for meat — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 9.2 Processed fish and fishery products including molluscs and crustaceans — several limitsPermitted as a member of Group I, Additives. ML = quantum satis; except E 425 ML = 10000 mg/kg; E 620 to E 625, ML = 10000 mg/kg individually or in combination, expressed as glutamic acid; E 626 to E 635, ML = 500 mg/kg individually or in combination, expressed as guanylic acid.
  • 9.3 fish roePermitted as a member of Group I, Additives. only processed fish roe.
Regulation (EC) No 1333/2008and 75 further provisionsretrieved 2026-10-18
Great BritainFood Standards Agency / Food Standards ScotlandPermitted, with conditions

73 food categories

highest permitted level 70,000 mg/kg or mg/l

Show every food category
  • 1.3 Unflavoured fermented milk products, heat-treated after fermentation — quantum satisPermitted as a member of Group I. quantum satis.
  • 1.4 Flavoured fermented milk products including heat-treated products — quantum satisPermitted as a member of Group I. quantum satis.
  • 1.6.3 Other creams — quantum satisPermitted as a member of Group I. quantum satis.
  • 1.7.1 Unripened cheese excluding products falling in category 16 — quantum satisPermitted as a member of Group I. quantum satis. except mozzarella.
  • 1.7.5 Processed cheese — quantum satisPermitted as a member of Group I. quantum satis.
  • 1.7.6 Cheese products (excluding products falling in category 16) — quantum satisPermitted as a member of Group I. quantum satis.
  • 1.8 Dairy analogues, including beverage whiteners — quantum satisPermitted as a member of Group I. quantum satis.
  • 1.9 Edible caseinates — quantum satisquantum satis.
  • 10.2 Processed eggs and egg products — quantum satisPermitted as a member of Group I. quantum satis.
  • 11.2 Other sugars and syrups — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.1.2 Salt substitutes — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.2.2 Seasonings and condiments — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.3 Vinegars and diluted acetic acid (diluted with water to 4-30 % by volume) — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.4 Mustard — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.5 Soups and broths — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.6 Sauces — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.7 Salads and savoury based sandwich spreads — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.8 Yeast and yeast products — quantum satisPermitted as a member of Group I. quantum satis.
  • 12.9 Protein products, excluding products covered in category 1.8 — quantum satisPermitted as a member of Group I. quantum satis.
  • 13.1.3 Processed cereal-based foods and baby foods for infants and young children as defined by Commission Directive 2006/125/EC — quantum satisquantum satis. only processed cereal-based foods and baby foods, only for pH adjustment.
  • 13.1.4 Other foods for young children — quantum satisquantum satis. only for pH adjustment.
  • 13.1.5.1 Dietary foods for infants for special medical purposes and special formulae for infants — quantum satisquantum satis. only for pH adjustment.
  • 13.2 Dietary foods for special medical purposes defined in Directive 1999/21/EC (excluding products from food category 13.1.5) — quantum satisPermitted as a member of Group I. quantum satis.
  • 13.3 Dietary foods for weight control diets intended to replace total daily food intake or an individual meal (the whole or part of the total daily diet) — quantum satisPermitted as a member of Group I. quantum satis.
  • 13.4 Foods suitable for people intolerant to gluten as defined by Commission Regulation (EC) No 41/2009 — quantum satisPermitted as a member of Group I. quantum satis. including dry pasta.
  • 14.1.2 Fruit juices as defined by Directive 2001/112/EC and vegetable juices — quantum satisPermitted as a member of Group I. quantum satis. only vegetable juices.
  • 14.1.3 Fruit nectars as defined by Directive 2001/112/EC and vegetable nectars and similar products — quantum satisPermitted as a member of Group I. quantum satis. only vegetable nectars, E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.1.4 Flavoured drinks — quantum satisPermitted as a member of Group I. quantum satis. E 420, E 421, E 953, E 965, E 966 and E 967 may not be used E 968 may not be used except where specifically provided for in this food category.
  • 14.1.5.2 Other — quantum satisPermitted as a member of Group I. quantum satis. excluding unflavoured leaf tea; including flavoured instant coffee; E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used in drinks.
  • 14.2.3 Cider and perry — quantum satisPermitted as a member of Group I. quantum satis. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.4 Fruit wine and made wine — quantum satisPermitted as a member of Group I. quantum satis. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.5 Mead — quantum satisPermitted as a member of Group I. quantum satis. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.6 Spirit drinks as defined in Regulation (EC) No 110/2008 — quantum satisPermitted as a member of Group I. quantum satis. except whisky or whiskey; E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used except in liqueurs.
  • 14.2.7.1 Aromatised wines — quantum satisPermitted as a member of Group I. quantum satis. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.7.2 Aromatised wine-based drinks — quantum satisPermitted as a member of Group I. quantum satis. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.7.3 Aromatised wine-product cocktails — quantum satisPermitted as a member of Group I. quantum satis. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 14.2.8 Other alcoholic drinks including mixtures of alcoholic drinks with non-alcoholic drinks and spirits with less than 15 % of alcohol — quantum satisPermitted as a member of Group I. quantum satis. E 420, E421, E 953, E965, E 966, E 967 and E 968 may not be used.
  • 15.1 Potato-, cereal-, flour- or starch-based snacks — quantum satisPermitted as a member of Group I. quantum satis.
  • 15.2 Processed nuts — quantum satisPermitted as a member of Group I. quantum satis.
  • 16 Desserts excluding products covered in categories 1, 3 and 4 — quantum satisPermitted as a member of Group I. quantum satis.
  • 17.1 Food supplements supplied in a solid form, excluding food supplements for infants and young children — quantum satisPermitted as a member of Group I. quantum satis. E 410, E 412, E 415, E 417 and E 425 may not be used to produce dehydrated food supplements intended to rehydrate on ingestion.
  • 17.2 Food supplements supplied in a liquid form, excluding food supplements for infants and young children — quantum satisPermitted as a member of Group I. quantum satis.
  • 18 Processed foods not covered by categories 1 to 17, excluding foods for infants and young children — quantum satisPermitted as a member of Group I. quantum satis.
  • 2.2.2 Other fat and oil emulsions including spreads as defined by Regulation (EC) No 1234/2007 and liquid emulsions — quantum satisPermitted as a member of Group I. quantum satis.
  • 2.3 Vegetable oil pan spray — quantum satisPermitted as a member of Group I. quantum satis.
  • 3 Edible ices — quantum satisPermitted as a member of Group I. quantum satis.
  • 4.2.1 Dried fruit and vegetables — quantum satisPermitted as a member of Group I. quantum satis. E 410, E 412, E 415 E 417 may not be used to produce dehydrated foods intended to rehydrate on ingestion.
  • 4.2.2 Fruit and vegetables in vinegar, oil, or brine — quantum satisPermitted as a member of Group I. quantum satis.
  • 4.2.4.1 Fruit and vegetable preparations excluding compote — quantum satisPermitted as a member of Group I. quantum satis.
  • 4.2.5.2 Jam, jellies and marmalades and sweetened chestnut puree as defined by Directive 2001/113/EC — quantum satisquantum satis.
  • 4.2.5.3 Other similar fruit or vegetable spreads — quantum satisquantum satis.
  • 4.2.5.4 Nut butters and nut spreads — quantum satisPermitted as a member of Group I. quantum satis.
  • 4.2.6 Processed potato products — quantum satisPermitted as a member of Group I. quantum satis.
  • 5.1 Cocoa and chocolate products as covered by Directive 2000/36/EC — quantum satisPermitted as a member of Group I. quantum satis. only energy-reduced or with no added sugar.
  • 5.1 Cocoa and chocolate products as covered by Directive 2000/36/EC — 70,000 mg/kg or mg/lAuthorised under E 524-528, Hydroxides. ML = 70000. Note (*): E 170, E 500-504, E 524-528 and E 530: 7 % on dry matter, without fat, expressed as potassium carbonates (1): The additives may be added individually or in combination.
  • 5.2 Other confectionery including breath refreshening microsweets — quantum satisPermitted as a member of Group I. quantum satis. The substances listed under numbers E 400, E 401, E 402, E 403, E 404, E 406, E 407, 407a, E 410, E 412, E 413, E 414, E 415, E 417, E 418, E 425 and E 440 may not be used in jelly mini-cups, defined, for the purpose of this Regulation, as jelly confectionery of a firm consistence, contained in semi rigid mini-cups or mini-capsules, intended to be ingested in a single bite by exerting pressure on the mini-cups or mini-capsule to project the confectionery into the mouth; E 410, E 412, E 415 E 417 may not be used to produce dehydrated foods intended to rehydrate on ingestion. E425 may not be used in jelly confectionery.
  • 5.3 Chewing gum — quantum satisPermitted as a member of Group I. quantum satis.
  • 5.4 Decorations, coatings and fillings, except fruit based fillings covered by category 4.2.4 — quantum satisPermitted as a member of Group I. quantum satis.
  • 6.2.2 Starches — quantum satisPermitted as a member of Group I. quantum satis.
  • 6.3 Breakfast cereals — quantum satisPermitted as a member of Group I. quantum satis.
  • 6.4.2 Dry pasta — quantum satisPermitted as a member of Group I. quantum satis. only gluten free and/or pasta intended for hypoproteic diets in accordance with Directive 2009/39/EC.
  • 6.4.4 Potato gnocchi — quantum satisPermitted as a member of Group I. quantum satis. except fresh refrigerated potato gnocchi.
  • 6.4.5 Fillings of stuffed pasta (ravioli and similar) — quantum satisPermitted as a member of Group I. quantum satis.
  • 6.5 Noodles — quantum satisPermitted as a member of Group I. quantum satis.
  • 6.6 Batters — quantum satisPermitted as a member of Group I. quantum satis.
  • 6.7 Pre-cooked or processed cereals — quantum satisPermitted as a member of Group I. quantum satis.
  • 7.1 Bread and rolls — quantum satisPermitted as a member of Group I. quantum satis. except products in 7.1.1 and 7.1.2.
  • 7.2 Fine bakery wares — quantum satisPermitted as a member of Group I. quantum satis.
  • 8.3.1 Non-heat-treated meat products — quantum satisPermitted as a member of Group I. quantum satis.
  • 8.3.2 Heat-treated meat products — quantum satisPermitted as a member of Group I. quantum satis. except foie gras, foie gras entier, blocs de foie gras, Libamáj, libamáj egészben, libamáj tömbben.
  • 8.3.3 Casings and coatings and decorations for meat — quantum satisPermitted as a member of Group I. quantum satis.
  • 9.2 Processed fish and fishery products including mollusks and crustaceans — quantum satisPermitted as a member of Group I. quantum satis.
  • 9.3 Fish roe — quantum satisPermitted as a member of Group I. quantum satis. only processed fish roe.
Assimilated Regulation (EC) No 1333/2008and 72 further provisionsretrieved 2026-10-18
JapanConsumer Affairs AgencyPermitted, with conditions
Designated additive: Appended Table 1, item 234, 水酸化ナトリウム（別名カセイソーダ） (“Sodium Hydroxide (Caustic Soda)” in the unofficial English translation). …

Designated additive: Appended Table 1, item 234, 水酸化ナトリウム（別名カセイソーダ） (“Sodium Hydroxide (Caustic Soda)” in the unofficial English translation). Standards for use — Specifications and Standards for Foods, Food Additives, etc. (MHW Notification No. 370 of 1959), Part II (Food Additives), F (Standards for use), entry 水酸化ナトリウム: (1) [must be removed or broken down before the food is finished] “水酸化ナトリウムは、最終食品の完成前に中和し、又は除去しなければならない。” The Japanese is the standard as published. There is no official English translation of the Notification; the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications for this additive, in the same Notification, are not imported and are not shown here; nor are the general rules in F 添加物一般, which apply to every additive.

Regulations for Enforcement of the Food Sanitation Act (MHW Ordinance No. 23 of 1948), Appended Table 1retrieved 2026-10-18
South KoreaMinistry of Food and Drug SafetyPermitted, with conditions
Designated food additive: Standards and Specifications for Food Additives, Part III, 1. …

Designated food additive: Standards and Specifications for Food Additives, Part III, 1. 일반식품첨가물 (general food additives), 수산화나트륨 (“Sodium Hydroxide”, the English the Code prints beside it); the Code marks it as also usable as a processing aid; 2. 가공보조제 (processing aids), 수산화나트륨 (“Sodium Hydroxide”, the English the Code prints beside it); the Code marks it as also usable as a general food additive. Main use (주용도) of 수산화나트륨: 산도조절제. Standard for use (사용기준) of 수산화나트륨: (1) [must be neutralised or removed before the final food is complete] “수산화나트륨은 최종식품 완성 전에 중화 또는 제거하여야 한다.” Main use (주용도) of 수산화나트륨: 제조용제. The Korean is the standard as published. There is no official English translation of the current Code (the English version on MFDS’s website is the 2020 edition and has no legal effect); the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications (Part IV) are not imported, nor are the general standards in Part II, which apply to every additive.

Standards and Specifications for Food Additives (식품첨가물의 기준 및 규격), MFDS Notification, Part III (Standards for use, by item)retrieved 2026-10-18
United StatesFood and Drug AdministrationPermitted21 CFR 184.1763retrieved 2026-10-17
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

8 food categories

highest permitted level 2,000 mg/kg

Show every food category and its notes
  • 01.1.2 Other Fluid Milk (plain) — GMP
    • Note 410 Excluding lactose reduced milks.
  • 01.2.1.2 Fermented milks (plain), heat-treated after fermentation — GMP
  • 01.8.2 Dried whey and whey products, excluding whey cheeses — GMP
    • Note XS331 Excluding products conforming to the Standard for Dairy Permeate Powders (CXS 331-2017).
  • 02.2.1 Butter — GMP
  • 13.1.1 Infant formulae — 2,000 mg/kg
    • Note 55 Within the limits for sodium, calcium, and potassium specified in the Standard for Infant Formula and Formulas for Special Medical Purposes Intended for Infants (CXS 72-1981): singly or in combination with other sodium, calcium, and/or potassium salts.
    • Note 551 Maximum use level is expressed as mg additive/L of food.
  • 13.1.2 Follow-up formulae — GMP
    • Note 316 For use in follow-up formula for older infants: within the limit for sodium specified in the standard for Follow-up Formula for older infants and product for young children (CXS 156-1987); singly or in combination with other sodium containing additives.
    • Note 551 Maximum use level is expressed as mg additive/L of food.
  • 13.1.3 Formulae for special medical purposes for infants — 2,000 mg/kg
    • Note 55 Within the limits for sodium, calcium, and potassium specified in the Standard for Infant Formula and Formulas for Special Medical Purposes Intended for Infants (CXS 72-1981): singly or in combination with other sodium, calcium, and/or potassium salts.
    • Note 551 Maximum use level is expressed as mg additive/L of food.
  • 13.2 Complementary foods for infants and young children — GMP
    • Note 320 Within the limit for sodium listed in the Codex Standard for Processed Cereal-based Foods for Infants and Young Children (CODEX STAN 74-1981) for foods corresponding to that standard : singly or in combination with other sodium containing additives.
    • Note XS73 Excluding products conforming to the Standard for Canned Baby Foods (CODEX STAN 73-1981).
CXS 192-1995 Table Three, INS 524and 8 further provisionsretrieved 2026-09-07

How much is permitted

A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.

Australia and New Zealand2,000 mg/kg1 numeric limit, 1 GMP
Canada—9 GMP, 1 no quantity stated
European Union70,000 mg/kg1 numeric limit, 46 several limits, 7 quantum satis, 22 no quantity stated
Great Britain70,000 mg/kg1 numeric limit, 72 quantum satis
Japan—1 no quantity stated
South Korea—1 no quantity stated
United States—1 no quantity stated
Codex Alimentarius2,000 mg/kg2 numeric limit, 7 GMP

What it is made from

Manufactured by the electrolysis of brine. It is corrosive as supplied and is handled as a processing aid rather than an ingredient.

  • Vegan
  • Vegetarian

Compare other additives on the dietary indexes.

CAS registry number
1310-73-2
InChIKey
HEMHJVSKTPXQMS-UHFFFAOYSA-M
PubChem
CID 14798

The two specifications, compared

The European Union sets identity and purity by regulation; JECFA publishes its own through FAO, advisory until a country adopts it. Both documents are below in full. These are the parameters each puts a number on.

ParameterEuropean UnionJECFA
Assayno less than 98 %stated in prose
Leadno more than 0.5 mg/kgno more than 2 mg/kg
Arsenicno more than 3 mg/kg—
Mercuryno more than 1 mg/kg—

One parameter differs between the two documents. A difference is not a disagreement about safety: the two are revised on their own cycles, and an assay or a drying loss can be measured against a different preparation of the substance, which is why only the contaminant ceilings are marked. Within the EU the EU's figure is the one that binds.

How the EU defines it

The legal specification an additive must meet to be sold as this E number in the EU — what it is, how it may be made, and the purity it must reach. From Commission Regulation (EU) No 231/2012.

E 524 Sodium hydroxide

Synonyms: Caustic soda; Lye

Assay, identification and purity criteria

Description and assay

Einecs
215-185-5
Chemical name
Sodium hydroxide
Chemical formula
NaOH
Molecular weight
40,0
Assay
Content of solid forms not less than 98,0 % of total alkali (as NaOH). Content of solutions accordingly, based on the stated or labelled percentage of NaOH
Description
White or nearly white pellets, flakes, sticks, fused masses or other forms. Solutions are clear or slightly turbid, colourless or slightly coloured, strongly caustic and hygroscopic and when exposed to the air they absorb carbon dioxide, forming sodium carbonate

Identification

Test for sodium
Passes test
pH
Strongly alkaline (1 % solution)
Solubility
Very soluble in water. Freely soluble in ethanol

Purity criteria

Water insoluble and organic matter
A 5 % solution is completely clear and colourless to slightly coloured
Carbonate
Not more than 0,5 % (as Na₂CO₃)
Arsenic
Not more than 3 mg/kg
Lead
Not more than 0,5 mg/kg
Mercury
Not more than 1 mg/kg

Commission Regulation (EU) No 231/2012, Annex, E 524

How JECFA defines it

The international specification for identity and purity, prepared by the Joint FAO/WHO Expert Committee on Food Additives and published by FAO. It is a different document from any above, written by a different body and revised on its own cycle; it is advisory, and a country adopts it or does not.

INS 524 Sodium Hydroxide

Synonyms: Caustic soda; Lye; Sodium hydrate

Assay, identification and purity criteria

Description and assay

Specification history
Prepared at the 19th JECFA (1975), published in NMRS 55B (1976) and in FNP 52 (1992). Metals and arsenic specifications revised at the 59th JECFA (2002). An ADI not limited' was established at the 9th JECFA (1965)
SYNONYMS DEFINITION Chemical names C.A.S. number Chemical formula Formula weight Assay DESCRIPTION FUNCTIONAL USES Solubility (Vol. 4) Test for alkali Test for sodium (Vol. 4) Water insoluble substances Carbonate
Caustic soda, lye, sodium hydrate, INS No. 524 Sodium hydroxide 1310-73-2 NaOH 40.00 Not less than 95.0% of total alkali calculated as NaOH White or nearly white pellets, flakes, sticks, fused masses or other forms Alkali Very soluble in water; freely soluble in ethanol A 1 in 100 solution of the sample is strongly alkaline Passes test 1 g of the sample dissolves completely in 20 ml of water and gives a clear and colourless solution Not more than 3% as sodium carbonate Each ml of 1 N sulfuric acid required between the phenolphthalein and methyl orange end-points in the Method of assay is equivalent to 106.0 mg of Na 2 CO 3

Purity criteria

Lead (Vol. 4)
Not more than 2 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.” .
METHOD OF
Dissolve about 1.5 g of the sample, accurately weighed, in 40 ml of recently boiled and cooled water, cool to 15 o , add phenolphthalein TS and titrate
ASSAY
with 1 N sulfuric acid. At the discharge of the pink colour, record the volume of acid required, then add methyl orange TS and continue to titrate to a persistent pink colour. Record the total volume of acid required for the titration. Each ml of 1 N sulfuric acid is equivalent to 40.00 mg of total alkali, calculated as NaOH.

FAO JECFA Monograph 1 (2006)

Authorised in other additives, enzymes, flavourings and nutrients

These authorisations are not for use in food. They let this substance be used inside another additive, a food enzyme, a flavouring or a nutrient preparation — often as a carrier — and it reaches food only as part of that product. Annex III to Regulation (EC) No 1333/2008.

PartMay be used inMaximum levelCitation
Annex III, Part 2: Food additives other than carriers in food additivesAll food additive preparationsAuthorised as a member of Table 1 of Part 6, listed as "Table 1" Note (1): Except enzymes authorised as food additives.quantum satisRegulation (EC) No 1333/2008, Annex III, Part 2, via Table 1 of Part 6
Annex III, Part 3: Food additives including carriers in food enzymesFood enzymesNote (1): Including enzymes authorised as food additives.In enzyme preparation: quantum satis In final food except beverages: quantum satis In beverages: quantum satisRegulation (EC) No 1333/2008, Annex III, Part 3
Annex III, Part 4: Food additives including carriers in food flavouringsAll flavouringsAuthorised as a member of Table 1 of Part 6, listed as "Table 1"quantum satisRegulation (EC) No 1333/2008, Annex III, Part 4, via Table 1 of Part 6
Annex III, Part 5, Section A: Food additives added in nutrients except in nutrients intended to be used in foodstuffs listed in Part E, point 01.10, of Annex II and foodstuffs for infants and young children listed in Part E, point 13.1, of Annex IIAll nutrientsquantum satisRegulation (EC) No 1333/2008, Annex III, Part 5, Section A

Every name it appears under

84 recorded names. A label may use any of them.

E number

  • E524

INS number

  • 524

CAS registry number

  • 1310-73-2
  • 81133-20-2

As it appears in regulation

  • Sodium hydroxide

Other names

  • Aetznatron
  • Ascarite
  • Ascarite II
  • Caswell No. 773
  • Caustic soda
  • Caustic soda, bead
  • Caustic soda, dry
  • Caustic soda, liquid
  • Collo-Grillrein
  • Collo-Tapetta
  • E 524
  • EPA Pesticide Chemical Code 075603
  • Fuers Rohr
  • HSDB 229
  • Hydroxide, Sodium
  • Hydroxyde de sodium
  • hydroxyl sodium
  • INS-524
  • Lewis-red devil lye
  • Liquid-plumr
  • Lye
  • NaOH
  • Natrii hydroxydum
  • Natrium causticum
  • Natrium-hydroxid, reinstes
  • Natriumhydroxid
  • Natriumhydroxyde
  • Plung
  • Promoter 3308b
  • Rohrputz
  • Rohrreiniger Rofix
  • Soda asbestos
  • Soda lye
  • Soda, caustic
  • Soda, hydrate
  • Soda, kaustische
  • Sodio(idrossido di)
  • sodium hydoxide
  • Sodium hydrate
  • sodium hydroxid
  • Sodium hydroxide
  • Sodium Hydroxide (0.1M in water (0.1N))
  • Sodium hydroxide (Na(OH))
  • Sodium hydroxide (Na2(OH)2)
  • Sodium hydroxide dimer
  • Sodium hydroxide pearls
  • Sodium hydroxide, flake
  • Sodium hydroxide, pellets
  • Sodium hydroxide, solid
  • Sodium hydroxide; NaOH
  • sodium hyroxide
  • Sodium(hydroxyde de)
  • sodiumhydroxid
  • sodiumhydroxide
  • soude caustique
  • Stamperprep
  • Tosoh pearl
  • UN 1823 (solid)
  • White caustic

Systematic names

  • Sodium;hydroxide

Hazard reference values

Values set by assessing bodies. A body that has not set a value is not listed here.
TypeValuePopulationAssessed byOpinion
ADInot limited—JECFA1965

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated rather than machine-read, and none has been written for this substance yet.

Common questions

Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.

What is E 524?
E 524 is Sodium hydroxide. Sodium hydroxide, or lye, is a strongly alkaline processing aid. It gives pretzels their crust and colour, cures olives, and produces hominy from maize; it is normally neutralised or washed out.
What is Sodium hydroxide used for in food?
It is listed as an acidity regulator — the role Canada, Codex and the US assign it. This page shows every function each regulator records, with the citation for each.
Where is Sodium hydroxide permitted?
Of the seven regulators this site reads, Australia and New Zealand, Canada, the EU, Great Britain, Japan, South Korea, the US and the Codex standard permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
Is Sodium hydroxide vegan?
Yes. Sodium hydroxide is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.

Sources for this page

  • anz retrieved 2026-10-17
  • ca retrieved 2026-10-17
  • eu retrieved 2026-10-18
  • gb retrieved 2026-10-18
  • jp retrieved 2026-10-18
  • kr retrieved 2026-10-18
  • ecfr retrieved 2026-10-17
  • gsfa retrieved 2026-09-07
  • euspecs retrieved 2026-10-18
  • jecfaspecs retrieved 2026-09-23

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable: a JSON record of this additive is given on request —how to ask for access.

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