Silicon dioxide

E number E551INS 551CAS 7631-86-9

Listed as an anticaking agent by Canada, Codex and the US.

Listed as anticaking agents (CA, US, Codex) · colours (US) · antioxidants (US) · emulsifiers (US) · humectants (US) · antifoaming agents (Codex) · flavouring agents and adjuvants (US) · carriers (Codex) · formulation aids (US) · lubricants and release agents (US)
Chemical structure of Silicon dioxide, from PubChem compound 24261
Structure from PubChem CID 24261 (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.

Silicon dioxide is an anticaking agent in powdered products such as spice blends, powdered drinks, grated cheese and salt, where it absorbs moisture and keeps particles separate.

Where it is and isn’t permitted

Status of Silicon dioxide 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

56 food categories

highest permitted level 10 mg/L

Show every food category
  • 0 Preparations of food additives — GMP
  • 1.1.1 Liquid milk (including buttermilk) — GMPOnly UHT goats milk.
  • 1.1.2 Liquid milk products and flavoured liquid milk — GMP
  • 1.2.2 Fermented milk products and rennetted milk products — GMP
  • 1.3 Condensed milk and evaporated milk — GMP
  • 1.4.1 Cream, reduced cream and light cream — GMPOnly UHT creams and creams receiving equivalent or greater heat treatments.
  • 1.4.2 Cream products (flavoured, whipped, thickened, sour cream etc) — GMP
  • 1.5 Dried milk, milk powder, cream powder — GMP
  • 1.6 Cheese and cheese products — GMP
  • 10.2 Liquid egg products — GMP
  • 10.3 Frozen egg products — GMP
  • 10.4 Dried or heat coagulated egg products — GMP
  • 11.1.1 Rainbow sugar — GMP
  • 11.3.1 Dried honey — GMP
  • 11.4 Tabletop sweeteners — GMP
  • 12.1.1 Salt — GMP
  • 12.1.2 Reduced sodium salt mixture — GMP
  • 12.1.3 Salt substitute — GMP
  • 12.5 Yeast and yeast products — GMP
  • 12.6 Vegetable protein products — GMP
  • 13.1 Infant formula products — 10 mg/LMay only be added as part of a nutrient preparation. Applies in Australia; New Zealand has not adopted Standard 2.9.1 (infant formula products) and applies its own infant formula standard.
  • 13.3 Formulated meal replacements and formulated supplementary foods — GMP
  • 13.4 Formulated supplementary sports foods — GMP
  • 13.5 Food for special medical purposes — GMP
  • 14.1.1.2 Carbonated, mineralised and soda waters — GMP
  • 14.1.2.1 Fruit and vegetable juices — GMPFor juice separated by other than mechanical means only.
  • 14.1.2.2 Fruit and vegetable juice products — GMP
  • 14.1.3 Water based flavoured drinks — GMP
  • 14.1.4 Formulated Beverages — GMP
  • 14.1.5 Coffee, coffee substitutes, tea, herbal infusions and similar products — GMP
  • 14.2.3 Wine based drinks and reduced alcohol wines — GMP
  • 14.2.4.1 Fruit wine products and vegetable wine products — GMP
  • 14.2.5 Spirits and liqueurs — GMP
  • 14.3 Alcoholic beverages not included in item 14.2 — GMP
  • 2.1 Edible oils essentially free of water — GMP
  • 2.2.1.2 Butter products — GMP
  • 2.2.1.3 Margarine and similar products — GMP
  • 2.2.2 Oil emulsions (<80% oil) — GMP
  • 20 Foods not included in items 0 to 14 — GMP
  • 3 Ice cream and edible ices — GMP
  • 4.1.3 Fruits and vegetables that are peeled, cut, or both peeled and cut — GMP
  • 4.3 Processed fruits and vegetables — GMP
  • 5.1 Chocolate and cocoa products — GMP
  • 5.2 Sugar confectionery — GMP
  • 5.4 Icings and frostings — GMP
  • 6.3 Processed cereal and meal products — GMP
  • 6.4 Flour products (including noodles and pasta) — GMP
  • 7 Breads and bakery products — GMP
  • 8.2 Processed meat, poultry and game products in whole cuts or pieces — GMP
  • 8.3 Processed comminuted meat, poultry and game products, other than products listed in item 8.3.2 — GMP
  • 8.3.2 Sausage and sausage meat containing raw, unprocessed meat — GMP
  • 8.4 Edible casings — GMP
  • 8.5 Animal protein products — GMP
  • 9.2 Processed fish and fish products — GMP
  • 9.3 Semi preserved fish and fish products — GMP
  • 9.4 Fully preserved fish including canned fish products — GMP
Food Standards Code, Schedule 15, S15—5and 55 further provisionsretrieved 2026-10-17
CanadaHealth CanadaPermitted, with conditions

highest permitted level 5,000 %

10 permitted uses

Show every permitted use
  • In: Cayenne pepper; Chili pepper; Chili powder; Paprika; Red pepper. Purpose: Anticaking agent. Limit: 2.0%. — Health Canada, List of Permitted Anticaking Agents (List 1), item S.1(a)
  • In: Celery pepper; Celery salt. Purpose: Anticaking agent. Limit: 5,000 ppm. — Health Canada, List of Permitted Anticaking Agents (List 1), item S.1(b)
  • In: Foods sold in tablet form. Purpose: Anticaking agent. Limit: Good Manufacturing Practice. — Health Canada, List of Permitted Anticaking Agents (List 1), item S.1(c)
  • In: Garlic salt; Onion salt. Purpose: Anticaking agent. Limit: If used singly, the amount not to exceed 1.0%. If used in any combination with other anticaking agents, the total combined amount not to exceed 2.0%, provided that the amount of silicon dioxide does not exceed 1.0%. — Health Canada, List of Permitted Anticaking Agents (List 1), item S.1(d)
  • In: Icing sugar. Purpose: Anticaking agent. Limit: Not to be used with starch in accordance with paragraph 15.1.5(b) of Volume 15 of the Food Compositional Standards Document. If used singly, the amount not to exceed 1.5%. If used in any combination with other anticaking agents, the total combined amount not to exceed 1.5%. — Health Canada, List of Permitted Anticaking Agents (List 1), item S.1(e)
  • In: Salt. Purpose: Anticaking agent. Limit: If used singly, the amount not to exceed 1.0%, or 2.0% in the case of fine grained salt. If used in any combination with other anticaking agents, the total combined amount not to exceed 1.0%, or 2.0% in the case of fine grained salt. This total combined amount does not include any of propylene glycol, potassium ferrocyanide or sodium ferrocyanide that may be added up to their respective maximum levels of use set out in this list. — Health Canada, List of Permitted Anticaking Agents (List 1), item S.1(f)
  • In: Unstandardized dry mixes. Purpose: Anticaking agent. Limit: Good Manufacturing Practice. — Health Canada, List of Permitted Anticaking Agents (List 1), item S.1(g)
  • In: Colouring agent formulations. Purpose: Colour stabilizer. Limit: Good Manufacturing Practice. Amendment notices: NOM/ADM-0041. — Health Canada, List of Permitted Food Additives with Other Purposes of Use (List 8), item S.2(a)
  • In: Edible vegetable oil-based cookware coating emulsions. Purpose: Suspending agent. Limit: 2.0%. — Health Canada, List of Permitted Food Additives with Other Purposes of Use (List 8), item S.2(b)
  • In: Modified sugar. Purpose: To increase dissolution rate. Limit: 2,000 ppm. Amendment notices: MFAA-2601. — Health Canada, List of Permitted Food Additives with Other Purposes of Use (List 8), item S.2(c)
Health Canadaand 9 further provisionsretrieved 2026-10-17
European UnionEuropean Commission / EFSAPermitted, with conditions

19 food categories

highest permitted level 30,000 mg/kg

Show every food category
  • 1.7.2 ripened cheese — 10,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 10000 mg/kg. only sliced or grated cheese hard and semi-hard cheese. Note 1: The additives may be added individually or in combination.
  • 1.7.5 processed cheese — 10,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 10000 mg/kg. Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 1.7.6 cheese products (excluding products falling in category 16) — 10,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 10000 mg/kg. only sliced or grated hard and semi-hard products Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 1.8 Dairy analogues, including beverage whiteners — 10,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 10000 mg/kg. only sliced or grated cheese analogues and processed cheese analogue; beverage whiteners Period of application: from 1 February 2014.
  • 11.1 Sugars and syrups as defined by directive 2001/111/ec — 10,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 10000 mg/kg. only dried powdered foods Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 11.4.2 table-top sweeteners in powder form — 10,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 10000 mg/kg. Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 11.4.3 table-top sweeteners in tablets — quantum satisPermitted as a member of Silicon dioxide - silicates. quantum satis.
  • 12.1.1 Salt — 10,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 10000 mg/kg. Period of application: from 1 February 2014.
  • 12.1.2 salt substitutes — 20,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 20000 mg/kg. Period of application: from 1 February 2014.
  • 12.2.2 Seasonings and condiments — 30,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 30000 mg/kg. only seasoning Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 13.1 foods for infants and young childrenin nutrient preparations.
  • 13.1.3 Processed cereal-based foods and baby foods as defined by Regulation (EU) No 609/2013 — 2,000 mg/kgML = 2000 mg/kg. only dry cereals.
  • 17.1 food supplements supplied in a solid form excluding food supplements for infants and young children’, — quantum satisPermitted as a member of Silicon dioxide - silicates. quantum satis. Period of application: from 1 February 2014.
  • 17.2 food supplements supplied in a liquid form excluding food supplements for Infants and young children — quantum satisPermitted as a member of Silicon dioxide - silicates. quantum satis. Period of application: from 1 February 2014.
  • 2.2.2 Other fat and oil emulsions including spreads as defined by Regulation (EC) No 1234/2007 and liquid emulsions — 30,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 30000 mg/kg. only tin greasing products Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 2.3 Vegetable oil pan spray — 30,000 mg/kgPermitted as a member of Silicon dioxide - silicates. ML = 30000 mg/kg. only tin greasing products Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 5.2 Other confectionery including breath freshening micro-sweets — quantum satisPermitted as a member of Silicon dioxide - silicates. quantum satis. surface treatment only Period of application: from 1 February 2014. Note 1: The additives may be added individually or in combination.
  • 5.3 chewing gum — quantum satisquantum satis. surface treatment only.
  • 5.4 Decorations, coatings and fillings, except fruit-based fillings covered by category 4.2.4 — quantum satisPermitted as a member of Silicon dioxide - silicates. quantum satis. surface treatment only Period of application: from 1 February 2014.
Regulation (EC) No 1333/2008and 18 further provisionsretrieved 2026-10-18
Great BritainFood Standards Agency / Food Standards ScotlandPermitted, with conditions

19 food categories

highest permitted level 30,000 mg/kg or mg/l

Show every food category
  • 0 All categories of foods — several limitsPermitted as a member of E 551 – 553: Silicon dioxide – silicates. (1) ML 10000: only foods in dried powdered form (i.e. foods dried during the production process, and mixtures thereof), excluding foods listed in Table 1 of Part A of this Annex; (2) quantum satis: only foods in tablet and coated tablet form, excluding the foods listed in Table 1 of Part A of this Annex. Note (1): The additives may be added individually or in combination. Note (57): The maximum level shall apply unless a different maximum level is specified in points 01 to 18 of this Annex in relation to individual foods or categories of foods.
  • 1.7.2 Ripened cheese — 10,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 10000. only sliced or grated cheese hard and semi-hard cheese Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 1.7.5 Processed cheese — 10,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 10000. Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 1.7.6 Cheese products (excluding products falling in category 16) — 10,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 10000. only sliced or grated hard and semi-hard products Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 1.8 Dairy analogues, including beverage whiteners — 10,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 10000. only sliced or grated cheese analogues and processed cheese analogue; beverage whiteners Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 11.1 Sugars and syrups as defined by Directive 2001/111/EC — several limitsPermitted as a member of E 551 – 553: Silicon dioxide – silicates. (1) quantum satis: only foods in tablet and coated tablet form Period of application: from 1 February 2014; (2) ML 10000: only dried powdered foods Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 11.4.2 Table-top sweeteners in powder form — 10,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 10000. Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 11.4.3 Table-top sweeteners in tablets — quantum satisPermitted as a member of E 551 – 553: Silicon dioxide – silicates. quantum satis. Period of application: from 1 February 2014.
  • 12.1.1 Salt — 10,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 10000. Period of application: from 1 February 2014.
  • 12.1.2 Salt substitutes — 20,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 20000. Period of application: from 1 February 2014.
  • 12.2.2 Seasonings and condiments — 30,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 30000. only seasoning Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 13.1.3 Processed cereal-based foods and baby foods for infants and young children as defined by Commission Directive 2006/125/EC — 2,000 mg/kg or mg/lML = 2000. only Dry cereals.
  • 17.1 Food supplements supplied in a solid form, excluding food supplements for infants and young children — quantum satisPermitted as a member of E 551 – 553: Silicon dioxide – silicates. quantum satis. Period of application: from 1 February 2014.
  • 17.2 Food supplements supplied in a liquid form, excluding food supplements for infants and young children — quantum satisPermitted as a member of E 551 – 553: Silicon dioxide – silicates. quantum satis. Period of application: from 1 February 2014.
  • 2.2.2 Other fat and oil emulsions including spreads as defined by Regulation (EC) No 1234/2007 and liquid emulsions — 30,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 30000. only tin greasing products Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 2.3 Vegetable oil pan spray — 30,000 mg/kg or mg/lPermitted as a member of E 551 – 553: Silicon dioxide – silicates. ML = 30000. only tin greasing products Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 5.2 Other confectionery including breath refreshening microsweets — quantum satisPermitted as a member of E 551 – 553: Silicon dioxide – silicates. quantum satis. surface treatment only Period of application: from 1 February 2014. Note (1): The additives may be added individually or in combination.
  • 5.3 Chewing gum — quantum satisquantum satis. surface treatment only.
  • 5.4 Decorations, coatings and fillings, except fruit based fillings covered by category 4.2.4 — quantum satisPermitted as a member of E 551 – 553: Silicon dioxide – silicates. quantum satis. surface treatment only Period of application: from 1 February 2014.
Assimilated Regulation (EC) No 1333/2008and 18 further provisionsretrieved 2026-10-18
JapanConsumer Affairs AgencyPermitted, with conditions
Designated additive: Appended Table 1, item 293, 二酸化ケイ素（別名シリカゲル） (“Silicon Dioxide (Silica Gel)” in the unofficial English translation). …

Designated additive: Appended Table 1, item 293, 二酸化ケイ素（別名シリカゲル） (“Silicon Dioxide (Silica Gel)” 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 二酸化ケイ素: (1) [may be used only for the uses stated] “二酸化ケイ素(微粒二酸化ケイ素を除く。)は、ろ過助剤以外の用途に使用してはならない。” (2) [must be removed or broken down before the food is finished] “二酸化ケイ素(微粒二酸化ケイ素を除く。)は、最終食品の完成前に除去しなければならない。” (3) [must not be used in the foods stated] “微粒二酸化ケイ素は、母乳代替食品及び離乳食品に使用してはならない。” (4) [sets maximum levels of use for the foods stated; sets a combined limit where it is used together with the additives stated] “微粒二酸化ケイ素の使用量は、二酸化ケイ素として、食品の2.0％以下でなければならない。また、ケイ酸カルシウムと併用する場合は、それぞれの使用量の和が食品(特定保健用食品たるカプセル及び錠剤並びに栄養機能食品たるカプセル及び錠剤を除く。)の2.0％以下でなければならない。” 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), 이산화규소 (“Silicon Dioxide”, the English the Code prints beside it); the Code marks it as also usable as a processing aid; 2. 가공보조제 (processing aids), 이산화규소 (“Silicon Dioxide”, the English the Code prints beside it); the Code marks it as also usable as a general food additive. Main use (주용도) of 이산화규소: 고결방지제, 거품제거제. Standard for use (사용기준) of 이산화규소: (1) [may be used only in the foods listed; sets a limit on the amount used] “이산화규소는 아래의 식품에 한하여 사용하여야 한다. 이산화규소의 사용량은 1. 가공유크림(자동판매기용 분말 제품에 한함)：1% 이하(규산마그네슘 또는 규산칼슘과 병용할 때에는 각각의 사용량의 합계가 1% 이하) 2. 분유류(자동판매기용에 한함)：1% 이하(규산마그네슘 또는 규산칼슘과 병용할 때에는 각각의 사용량의 합계가 1% 이하) 3. 식염：2% 이하(규산마그네슘 또는 규산칼슘과 병용할 때에는 각각의 사용량의 합계가 2% 이하) 4. 상기 식품을 제외한 식품과 건강기능식품 : 2% 이하” Main use (주용도) of 이산화규소: 여과보조제. Standard for use (사용기준) of 이산화규소: (1) [must be removed before the final food is complete] “이산화규소는 최종식품 완성 전에 제거하여야 한다.” 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 AdministrationPermitted, with conditions21 CFR 172.480retrieved 2026-10-17
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

13 food categories

highest permitted level 15,000 mg/kg

Show every food category and its notes
  • 01.5.1 Milk powder and cream powder (plain) — GMP
    • Note 544 Except for use in products conforming to the Standard for Milk Products and Cream Powder (CXS 207-1999): bone phosphate (INS 542), calcium carbonate (INS 170(i)), calcium dihydrogen phosphate (INS 341(i)), calcium hydrogen phosphate (INS 341(ii)), calcium silicate (INS 552), magnesium carbonate (INS 504(i)), magnesium dihydrogen phosphate (INS 343(i)), magnesium hydrogen phosphate (INS 343(ii)), magnesium oxide (INS 530), magnesium silicate, synthetic (INS 553(i)), silicon dioxide, amorphous (INS 551), talc (INS 553(iii)), tricalcium phosphate (INS 341(iii)), and trimagnesium phosphate (INS 343(iii)) as anticaking agents only, singly or in combination at 10,000 mg/kg.
    • Note 549 Except for use in products conforming to the Standard for Edible Casein Products (CXS 290-1995): bone phosphate (INS 542), calcium carbonate (INS 170(i)), calcium silicate (INS 552), hydroxypropyldistarch phosphate (INS 1442), magnesium carbonate (INS 504(i)), magnesium oxide (INS 530), magnesium silicate, synthetic (INS 553(i)), microcrystalline cellulose (cellulose gel) (INS 460(i)), powdered cellulose (INS 460(ii)), silicon dioxide, amorphous (INS 551), talc (INS 553(iii)), calcium dihydrogen phosphate (INS 341(i)), calcium hydrogen phosphate (INS 341(ii)), tricalcium phosphate (INS 341(iii)) magnesium dihydrogen phosphate (INS 343(i)), magnesium hydrogen phosphate (INS 343(ii)) and trimagnesium phosphate (INS 343(iii)), as anticaking agents only, singly or in combination at 4,400 mg/kg, noting the total amount of phosphorus shall not exceed 4,400 mg/kg.
  • 01.6.1 Unripened cheese — GMP
    • Note 3 For use in surface treatment only.
    • Note 488 Except for use in products conforming to the Group Standard for Unripened Cheese including Fresh Cheese (CXS 221-2001): silicon dioxide, amorphous (INS 551), calcium silicate (INS 552), magnesium silicate, synthetic (INS 553(i)) and talc (INS 553(iii)) , singly or in combination, as anticaking agents for the surface treatment of sliced, cut, shredded or grated cheese only, at 10,000 mg/kg as silicon dioxide.
    • Note 563 Except for use in products conforming to the Standard for Mozzarella (CXS 262-2006): calcium silicate (INS 552), magnesium silicate, synthetic (INS 553(i)), silicon dioxide, amorphous (INS 551) and talc (INS 553(iii)) for the surface treatment of sliced, cut, shredded or grated low moisture Mozzarella or for the surface treatment of shredded and/or diced high moisture Mozzarella, as anticaking agents only at 10,000 mg/kg, singly or in combination, as silicon dioxide.
    • Note XS273 Excluding products conforming to the Standard for Cottage Cheese (CXS 273-1968).
    • Note XS275 Excluding products conforming to the Standard for Cream Cheese (CXS 275-1973).
  • 01.6.2.1 Ripened cheese, includes rind — GMP
    • Note 459 Except for use at 10,000 mg/kg, singly or in combination: silicon dioxide, amorphous (INS 551), calcium silicate (INS 552), magnesium silicate, synthetic (INS 553(i)) and talc (INS 553(iii)) in products conforming to the Standards for Cheddar (CXS 263-1966), Danbo (CXS 264-1966) Edam (CXS 265-1966), Gouda (CXS 266-1966), Havarti (CXS 267-1966), Samsø (CXS 268-1966), Emmental (CXS 269-1967), Tilsiter (CXS 270-1968), Saint-Paulin (CXS 271-1968) and Provolone (CXS 272-1968), as anticaking agents only: silicates calculated as silicon dioxide.
    • Note 461 For the surface treatment of sliced, cut, shredded or grated cheese for products conforming to the Standards for Cheddar (CXS 263-1966), Danbo (CXS 264-1966) Edam (CXS 265-1966), Gouda (CXS 266-1966), Havarti (CXS 267-1966), Samsø (CXS 268-1966), Emmental (CXS 269-1967), Tilsiter (CXS 270-1968), Saint-Paulin (CXS 271-1968) and Provolone (CXS 272-1968) only as anticaking agents
    • Note 502 Except for use in surface treatment of sliced, cut, shredded or grated cheese only for products conforming to the General Standard for Cheese (CXS 283-1978): silicon dioxide, amorphous (INS 551), calcium silicate (INS 552), magnesium silicate, synthetic (INS 553(i)) and talc (INS 553(iii)) as anticaking agents at 10,000 mg/kg, as silicon dioxide, singly or in combination.
    • Note XS208 Excluding products conforming to the Standard for Cheese in Brine (CODEX STAN 208-1999).
    • Note XS274 Excluding products conforming to the Standard for Coulommiers (CXS 274-1969).
    • Note XS276 Excluding products conforming to the Standard for Camembert (CXS 276-1973).
    • Note XS277 Excluding products conforming to the Standard for Brie (CXS 277-1973).
    • Note XS278 Excluding products conforming to the Standard for Extra Hard Grating Cheese (CXS 278-1978).
  • 01.8.2 Dried whey and whey products, excluding whey cheeses — 10,000 mg/kg
    • Note XS331 Excluding products conforming to the Standard for Dairy Permeate Powders (CXS 331-2017).
  • 11.1.2 Powdered sugar, powdered dextrose — 15,000 mg/kg
    • Note 56 Excluding products where starch is present.
    • Note 465 For products conforming to the Standard for Sugars (CXS 212-1999) as anticaking agents only: Calcium dihydrogen phosphate (INS 341(i)), calcium hydrogen phosphate (INS 341(ii)), tricalcium phosphate (INS 341(iii)), magnesium dihydrogen phosphate (INS 343(i)), magnesium hydrogen phosphate (INS 343(ii), trimagnesium phosphate (INS 343(iii)), magnesium carbonate (INS 504(i)), bone phosphate (INS 542), silicon dioxide, amorphous (INS 551), calcium silicate (INS 552), and magnesium silicate, synthetic (INS 553(i)) singly or in combination but still within prescribed separate individual maximum levels.
  • 12.1.1 Salt — GMP
  • 12.1.2 Salt substitutes — GMP
  • 12.2.1 Herbs and spices — GMP
    • Note 51 For use in herbs only.
    • Note 534 For herbs use is limited to herbs that have been ground or processed into powder only, as an anticaking agent.
    • Note XS326 Excluding products conforming to the Standard for Black, White and Green Peppers (CODEX STAN 326-2017).
    • Note XS351 Excluding products conforming to the Standard for Dried Floral Parts - Saffron (CXS 351-2022).
  • 13.1.1 Infant formulae — 10 mg/kg
    • Note 589 For use as a nutrient carrier in a raw material or other ingredient.
    • Note 551 Maximum use level is expressed as mg additive/L of food.
  • 13.1.2 Follow-up formulae — 10 mg/kg
    • Note 589 For use as a nutrient carrier in a raw material or other ingredient.
    • Note 551 Maximum use level is expressed as mg additive/L of food.
  • 13.1.3 Formulae for special medical purposes for infants — 10 mg/kg
    • Note 589 For use as a nutrient carrier in a raw material or other ingredient.
    • Note 551 Maximum use level is expressed as mg additive/L of food.
  • 13.2 Complementary foods for infants and young children — 2,000 mg/kg
    • Note 318 In dry cereal only.
    • Note 284 For use only as a nutrient carrier in a raw material or other ingredient used to produce the foods conforming to the Standard for canned baby foods (CXS 73-1981) at 10 mg/kg in the food as consumed.
    • Note 304 When used as a nutrient carrier in a raw material or other ingredient used to produce the foods conforming to the Standard for processed cereal-based foods for infants and young children (CXS 74-1981), use level is 10 mg/kg in the food as consumed.
  • 14.1.5 Coffee, coffee substitutes, tea, herbal infusions, and other hot cereal and grain beverages, excluding cocoa — GMP
    • Note 321 For use in powdered mixes only.
CXS 192-1995 Table Three, INS 551and 13 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 Zealand10 mg/kg1 numeric limit, 55 GMP
Canada2,000 mg/kg – 20,000 mg/kg4 numeric limit, 3 GMP, 3 no quantity stated
European Union2,000 mg/kg – 30,000 mg/kg12 numeric limit, 6 quantum satis, 1 no quantity stated
Great Britain2,000 mg/kg – 30,000 mg/kg11 numeric limit, 2 several limits, 6 quantum satis
Japan—1 no quantity stated
South Korea—1 no quantity stated
United States—1 no quantity stated
Codex Alimentarius10 mg/kg – 15,000 mg/kg6 numeric limit, 8 GMP

GRAS notices to the FDA

A GRAS notice is a company’s conclusion that a substance is generally recognised as safe for the use it describes. FDA’s letter responds to that conclusion, for that notifier and that use. It is not a listing in 21 CFR, and it is not counted as a US permission above. The substance and use are as FDA’s inventory words them; this site matched the notice to this page by exact name.

  • GRN No. 298 · Silicon dioxide · Cabot Corporation

    Intended use: Use in a variety of foods and food-packing materials

    FDA’s response (2009-10-09): At the notifier's request, FDA ceased to evaluate this notice

What it is made from

Produced synthetically by precipitation or flame hydrolysis, giving a very fine amorphous powder. This is amorphous silica, which regulators treat separately from crystalline silica.

  • Vegan
  • Vegetarian

Compare other additives on the dietary indexes.

CAS registry number
7631-86-9
InChIKey
VYPSYNLAJGMNEJ-UHFFFAOYSA-N
PubChem
CID 24261

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 99 %stated in prose
Loss on dryingno more than 2.5 %stated in prose
Leadno more than 5 mg/kg—
Arsenicno more than 3 mg/kg—
Mercuryno more than 1 mg/kg—

The two documents state the same figures for every parameter compared here.

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 551 Silicon dioxide

Silicon dioxide is an amorphous substance, which is produced synthetically by either a vapour-phase hydrolysis process, yielding fumed silica, or by a wet process, yielding precipitated silica, silica gel, or hydrous silica. Fumed silica is produced in essentially an anhydrous state, whereas the wet-process products are obtained as hydrates or contain surface absorbed water

Synonyms: Silica; Silicium dioxide

Assay, identification and purity criteria

Description and assay

Einecs
231-545-4
Chemical name
Silicon dioxide
Chemical formula
(SiO₂)ₙ
Molecular weight
60,08 (SiO₂)
Assay
Content after ignition not less than 99,0 % (fumed silica) or 94,0 % (hydrated forms)
Description
White, fluffy powder or granules. Hygroscopic

Identification

Test for silica
Positive

Purity criteria

Loss on drying
Not more than 2,5 % (fumed silica, 105 °C, 2 hours) Not more than 8,0 % (precipitated silica and silica gel, 105 °C, 2 hours) Not more than 70 % (hydrous silica, 105 °C, 2 hours)
Loss on ignition
Not more than 2,5 % after drying (1 000 °C, fumed silica) Not more than 8,5 % after drying (1 000 °C, hydrated forms)
Soluble ionisable salts
Not more than 5,0 % (as Na₂SO₄)
Arsenic
Not more than 3 mg/kg
Lead
Not more than 5 mg/kg
Mercury
Not more than 1 mg/kg

Commission Regulation (EU) No 231/2012, Annex, E 551

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 551 Silicon Dioxide, Amorphous

Silicon dioxide is an amorphous substance, which is produced synthetically by either a thermal process, yielding pyrogenic (fumed) silica, or by a wet process, yielding hydrated silica, precipitated silica and silica gel. Pyrogenic silica is produced in an essentially anhydrous state, whereas the wet process products are obtained as hydrates or contain surface a d sorbed water.

Synonyms: Silica; INS No. 551; Synthetic amorphous silica (SAS); Silicon dioxide

Assay, identification and purity criteria

Description and assay

Specification history
1 out of 3 Prepared at the 84th JECFA and published in FAO JECFA Monographs 20 (2017), superseding tentative specifications prepared at the 80th JECFA (2015) and published in FAO JECFA Monographs 17 (2015). An ADI 'not specified' for silicon dioxide and certain silicates was established at the 29th JECFA (1985).
Chemical names
Silicon dioxide, chemically prepared
C.A.S. number
7631-86-9 112945-52-5 (pyrogenic silica) 112696-00-8 (hydrated silica)
Chemical formula
(SiO 2 ) x
Formula weight
60.08 (SiO 2 )
Assay
Pyrogenic (fumed) silica: Not less than 99% of SiO 2 on the ignited basis Hydrated silica (precipitated silica and silica gel): Not less than 94% of SiO 2 on the ignited basis
DESCRIPTION
Pyrogenic (fumed) silica: A pyrogenic silicon dioxide occurring as a fine, white amorphous powder or granules Hydrated silica (precipitated silica and silica gel): A precipitated, hydrated silicon dioxide occurring as a fine, white amorphous powder or granules 2 out of 3
FUNCTIONAL USES
Anticaking agent, carrier
METHOD OF ASSAY
Accurately weigh an appropriate quantity of the sample, (depending on the moisture content) equivalent to about 0.5 g of dried sample, in a platinum or nickel crucible, add 5 g potassium hydroxide and 2 g boric acid, mix and melt completely using a torch burner and allow to stand at room temperature. Place the reaction product along with crucible into 150 mL hot deionized water in a 250-mL PTFE beaker and dissolve residue by agitation. Wash the crucible with hot deionized water and remove it. Add 50 mL hydrochloric acid and transfer the contents into a 250-mL polypropylene volumetric flask. Wash the beaker three times with hot deionized water. Transfer the washings to the volumetric flask and make up to volume (Solution A). Prepare the test solution by diluting Solution A with 2% hydrochloric acid, to get the readings within the standard curve range. Analyse silica in the test solution by ICP-AES technique (Vol. 4). Set instrument parameters as specified by the instrument manufacturer, use the analytical line for Si (251.611 nm) and construct standard curve using standard solutions 0.1 – 5.0 μg/mL. Read the concentration of Si in test solution (as μg/mL) and calculate the silicon dioxide content of the sample using the formula: SiO2 (%) = (2.139 x C x 250 x DF) / (W x 106) x 100 Where: - C is concentration of Si in the test solution, μg/mL; - DF is dilution factor (dilution of solution A to get test solution); - W is weight of sample on the ignited basis, g

Identification

Test for silicon
Passes test See description under TESTS
Solubility (Vol. 4)
Insoluble in water and insoluble in ethanol
pH (Vol. 4)
Pyrogenic (fumed) silica: 3.0 – 5.0 (5% slurry, 20°) Hydrated silica (precipitated silica and silica gel): 4.0 - 9.0 (5% slurry, 20°)
Test for silicon
Prepare the test solution as shown under method of assay. Analyse silicon in the test solution by ICP-AES technique (Vol. 4). Set instrument parameters as specified by the instrument manufacturer, use the analytical lines for Si (251.611 nm). 3 out of 3

Purity criteria

Loss on drying (Vol. 4)
Pyrogenic (fumed) silica: Not more than 2.5% (105°, 2 h) Hydrated silica (precipitated silica and silica gel): Not more than 8% (105°, 2 h)
Loss on ignition (Vol. 4)
Pyrogenic (fumed) silica: Not more than 2.5% (1000°, 1h on dried sample) Hydrated silica (precipitated silica and silica gel): Not more than 8.5% (1000°, 1 h on dried sample)
Impurities soluble in 0.5M hydrochloric acid
Lead: Not more than 3 mg/kg Arsenic: Not more than 1 mg/kg Determine using a method appropriate to the specified level. See description under TESTS for sample preparation
Test: Impurities soluble in 0.5 M hydrochloric acid
Extract a known quantity of finely ground sample in a closed digestion system with 0.5 M hydrochloric acid (spectroscopic grade) for 30 min. Let solution cool, then filter through a 0.1 μm membrane filter. Wash the filter twice with hot 0.5 M hydrochloric acid and dilute to a known volume with 0.5 M hydrochloric acid.

FAO JECFA Monograph 20 (2017)

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 1: Carriers in food additivesEmulsifiers and coloursquantum satisRegulation (EC) No 1333/2008, Annex III, Part 1
Annex III, Part 2: Food additives other than carriers in food additivesDry powdered colour preparationsNote (1): Except enzymes authorised as food additives.50 000 mg/kg in the preparationRegulation (EC) No 1333/2008, Annex III, Part 2
Annex III, Part 2: Food additives other than carriers in food additivesDry powdered extracts of rosemary (E 392)Note (1): Except enzymes authorised as food additives.30 000 mg/kg in the preparationRegulation (EC) No 1333/2008, Annex III, Part 2
Annex III, Part 2: Food additives other than carriers in food additivesDry powdered preparations of emulsifiersNote (1): Except enzymes authorised as food additives.50 000 mg/kg in the preparationRegulation (EC) No 1333/2008, Annex III, Part 2
Annex III, Part 2: Food additives other than carriers in food additivesDry powdered preparations of polyolsNote (1): Except enzymes authorised as food additives.10 000 mg/kg in the preparationRegulation (EC) No 1333/2008, Annex III, Part 2
Annex III, Part 2: Food additives other than carriers in food additivesE 1209 polyvinyl alcohol-polyethylene glycol-graft-co-polymerNote (1): Except enzymes authorised as food additives.5 000 mg/kg in the preparationRegulation (EC) No 1333/2008, Annex III, Part 2
Annex III, Part 2: Food additives other than carriers in food additivesE 252 Potassium nitrateNote (1): Except enzymes authorised as food additives.10 000 mg/kg in the preparationRegulation (EC) No 1333/2008, Annex III, Part 2
Annex III, Part 2: Food additives other than carriers in food additivesE 508 potassium chloride and E 412 guar gum preparationsNote (1): Except enzymes authorised as food additives.10 000 mg/kg in the preparationRegulation (EC) No 1333/2008, Annex III, Part 2
Annex III, Part 3: Food additives including carriers in food enzymesFood enzymesCan be used as a carrier: Yes Note (1): Including enzymes authorised as food additives.In enzyme preparation: 50 000 mg/kg in the dry powdered preparation 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 flavourings50 000 mg/kg in flavouringsRegulation (EC) No 1333/2008, Annex III, Part 4
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 IIIn dry powdered preparations of all nutrientsListed jointly as "E 551, E 552 Silicon dioxide Calcium silicate"50 000 mg/kg in the dry powdered preparation (singly or in combination)Regulation (EC) No 1333/2008, Annex III, Part 5, Section A
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 IIIn potassium chloride preparations used in salt substitutesListed jointly as "E 551, E 552 Silicon dioxide Calcium silicate"10 000 mg/kg in the preparation (E 551 only)Regulation (EC) No 1333/2008, Annex III, Part 5, Section A
Annex III, Part 5, Section B: Food additives added 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 IIDry powdered nutrient preparations (food category: Foods for infants and young children and foods mentioned in Part E, point 01.10, of Annex II)10 000 mg/kg in nutrient preparationsRegulation (EC) No 1333/2008, Annex III, Part 5, Section B

Every name it appears under

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

E number

  • E551

INS number

  • 551

CAS registry number

  • 7631-86-9

As it appears in regulation

  • Silicon dioxide

Other names

  • Acticel
  • Aerogel 200
  • Aerosil 200
  • Aerosil 300
  • Aerosil 380
  • Aerosil A 300
  • Aerosil E 300
  • Aerosil K 7
  • Amorphous silica dust
  • Cab-o-sil M-5
  • Carplex
  • Carplex 30
  • Carplex 80
  • colloidal silica
  • Corasil II
  • Diatomaceous silica
  • Dioxosilane
  • Dri-Die
  • E 551
  • ETJ7Z6XBU4
  • Extrusil
  • INS NO.551
  • Ludox hs 40
  • Manosil vn 3
  • Min-U-Sil
  • Nalfloc N 1050
  • Neosil
  • Neosyl
  • Porasil
  • Positive sol 130M
  • Positive sol 232
  • Quartz (SiO2)
  • Quso 51
  • Quso G 30
  • Santocel
  • Silanox 101
  • Silica
  • Silica crystalline quartz
  • Silica, amorphous
  • Silica, colloidal
  • Silicic anhydride
  • Silicium dioxide
  • Silicon dioxide
  • Silicon dioxide (amorphous)
  • Silicon dioxide, fumed
  • Silicone dioxide
  • Silikil
  • Sillikolloid
  • Siloxid
  • Sipernat
  • Snowtex 30
  • Snowtex O
  • Syton 2X
  • Tokusil TPLM
  • Ultrasil VH 3
  • Ultrasil VN 3
  • Vitasil 220
  • Vulkasil S
  • Wessalon
  • White carbon
  • Zeofree 80
  • Zipax
  • Zorbax sil

Systematic names

  • dioxosilane

The EU re-evaluation programme

Every additive authorised in the EU before 20 January 2009 was put back through EFSA by Commission Regulation (EU) No 257/2010, and this one is named in it. What the Regulation required is below; whether the opinion has since been published is not something this site records.

  • To be evaluated by 31 December 2016. Named in Annex II, Part II, point 3 as “Silicon dioxide”, among the additives given priority within its class.

Hazard reference values

EFSA and JECFA have both assessed Silicon dioxide and their conclusions are not two comparable figures — EFSA records not allocated, JECFA not specified. An acceptable daily intake is a reference value set by a committee, not a threshold above which harm begins. “Not specified”, “not limited” and “not allocated” are conclusions, not missing data, and they are shown in the words each body used rather than reduced to a number. See where the two committees differ.

Values set by assessing bodies. A body that has not set a value is not listed here.
TypeValuePopulationAssessed byOpinion
ADInot allocatedconsumersEFSA FAF2024
ADInot specified—JECFA2015

Evidence and how bodies read it

What assessing bodies concluded

Each conclusion is paraphrased in the body's own framing, from the published opinion linked beneath it. Where bodies differ, both stand; this site does not adjudicate between them or add a view of its own.

  1. EFSA 2024

    In a follow-up that added nano-specific considerations, the FAF Panel considered it inappropriate to derive an ADI for silicon dioxide (E 551) and instead used a margin of exposure approach. It concluded that E 551 does not raise a safety concern for any population group, including infants below 16 weeks, at reported uses, while noting uncertainty about effects of nanosize aggregates.

    Source document

  2. EFSA 2018

    The ANS Panel found no indication of toxicity of silicon dioxide (E 551) at reported uses and use levels and no genotoxicity concern, but was unable to confirm the ADI 'not specified' because of database limitations, including the absence of a long-term study covering nanoparticles. It concluded that the EU specifications were insufficient to characterise the additive and recommended adding particle size distribution.

    Source document

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 551?
E 551 is Silicon dioxide. Silicon dioxide is an anticaking agent in powdered products such as spice blends, powdered drinks, grated cheese and salt, where it absorbs moisture and keeps particles separate.
What is Silicon dioxide used for in food?
It is listed as an anticaking agent — the role Canada, Codex and the US assign it. This page shows every function each regulator records, with the citation for each.
Where is Silicon dioxide 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 Silicon dioxide vegan?
Yes. Silicon dioxide 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.

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