E551Silicon dioxide

E551 is silicon dioxide (amorphous) (dioxyd silic vô định hình). In Appendix 1 of Circular 24/2019/TT-BYT its function is anticaking agent, antifoaming agent and carrier.

Did you know? According to EFSA (2018), the synthetic amorphous silica used as E551 includes fumed (pyrogenic) silica and hydrated silica (precipitated silica, silica gel), depending on whether a thermal or a wet process is used to make it.

Code: E551 · INS 551
Group: Anticaking agent, Antifoaming agent, Carrier

In Vietnam✓ PermittedOn the list of permitted additives — Circular 24/2019, Appendix 1

Risk level on the Yenzo Scalelow?Based on the Open Food Facts additives taxonomy

How E551 appears on labels

IngredientsIllustrative example

Wheat flour, vegetable oil, salt, sugar, anticaking agent (551), dried onion and garlic, pepper, natural colour (160a).

anticaking agent (551)anticaking agent 551E551INS 551On Vietnamese labels: Dioxyd silic vô định hình

Silicon dioxide in food

Dried whey and whey products

Powdered sugar, powdered dextrose

Salt

Salt substitutes

Complementary foods for children up to 36 months (dry cereals only)

Infant and young-child formula

Coffee, tea, herbal drinks

Questions about silicon dioxide

What is E551 (silicon dioxide)?

E551 is silicon dioxide (amorphous). In Appendix 1 of Circular 24/2019/TT-BYT the functions listed for it are anticaking agent, antifoaming agent and carrier.

Is silicon dioxide harmful?

In 2024 EFSA concluded that E551 raises no safety concern in any population group at the reported uses and use levels. Because the data are limited, EFSA found it not appropriate to set an ADI and used a margin of exposure (MOE) approach instead, requiring at least 36; the calculated MOEs were all above 36. EFSA also noted remaining uncertainty because few studies used a proper dispersion protocol (apart from those on effects on genetic material) for nano-sized aggregates.

Is INS 551 permitted in Vietnam?

Yes. Silicon dioxide (amorphous) (INS 551) is listed in Appendix 1 of Circular 24/2019/TT-BYT, the list of additives permitted in food, with the function anticaking agent, antifoaming agent and carrier.

Can children and pregnant women have E551?

In 2024 EFSA concluded that the use of E551 in food for infants below 16 weeks of age (food categories 13.1.1 and 13.1.5.1) raises no safety concern at current exposure levels. If you have a particular health condition, ask a doctor.

Other anticaking agents

E552Calcium silicatelow E553Magnesium silicates or talc (type not printed)low E553aMagnesium silicateslow E553bTalclow E554Sodium aluminium silicatemoderate E555Potassium aluminium silicatehigh

See all anticaking agents →

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Updated 21 October 2026

How Yenzo scores

Sources (4)

Information only, not medical advice. The risk level is the additive's class in Yenzo's open scoring method, based on the cited source.