Silicon dioxide is the additive the food industry lists as E551. In our table it is no risk identified: it takes no points off a product's score.
- The key finding, from EFSA: 'E 551 does not raise a safety concern in any population group, including infants under 16 weeks'; no ADI derived (MOE approach used) in the absence of a genotoxicity concern; EFSA recommends tighter specification limits for lead, mercury, arsenic and a new limit for aluminium (EFSA Journal 2024;22(10):8880, doi:10.2903/j.efsa.2024.8880, Re-evaluation of silicon dioxide (E 551) for infants below 16 weeks and follow-up for all population groups)
- No child flag. The class, and the points it costs, are the same for a child of any age.
- Where you meet it. It turns up in 22 of the 10,000 packaged foods scanned most on Open Food Facts, most often in chips and ready meals. Nine in ten of those foods are sold in Europe (counted 26 Sep 2026).
- 2 citations from EFSA, each one below.
What Silicon dioxide does to a score
A packaged food's additive subscore starts at 100 and loses points for each additive on the label; that subscore is a third of the final score. Silicon dioxide takes no points off a product's score. Scan the pack in Sito and the score you get is the one for your own child's age, with this additive named in the reasons. How we score has the whole method.
See what is in your own cupboard
Scan a packaged food and Sito names the additives in it, then scores the product out of 100 for your child's age.
What the sources found
Every classification in our table comes from the citations below, and nothing else. Each finding is our one-line summary of what the source concluded, with the source and reference beside it.
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EFSA
Journal 2024;22(10):8880 — doi:10.2903/j.efsa.2024.8880, Re-evaluation of silicon dioxide (E 551) for infants below 16 weeks and follow-up for all population groups
'E 551 does not raise a safety concern in any population group, including infants under 16 weeks'; no ADI derived (MOE approach used) in the absence of a genotoxicity concern; EFSA recommends tighter specification limits for lead, mercury, arsenic and a new limit for aluminium. -
EFSA
Journal 2018;16(1):5088 — doi:10.2903/j.efsa.2018.5088, Re-evaluation of silicon dioxide (E 551)
No concern for genotoxicity, including studies with nano-sized silicon dioxide; SCF group 'ADI not specified' noted.
Why this class
Clean current EFSA and FDA status. These rows exist so that an unfamiliar additive is never treated as a bad one: a missing row costs a product nothing, and a clean row says so with citations.
Our confidence in this row's classification is high. Medium or low does not mean the evidence is weak; it means something about the row is still being pinned down, usually a regulatory status confirmed from one source rather than two.
Questions parents ask
Is Silicon dioxide (E551) safe for kids?
No risk identified. No regulator finding we score, so a product keeps its full additive subscore in Sito. The current status is clean: 'E 551 does not raise a safety concern in any population group, including infants under 16 weeks'; no ADI derived (MOE approach used) in the absence of a genotoxicity concern; EFSA recommends tighter specification limits for lead, mercury, arsenic and a new limit for aluminium (EFSA Journal 2024;22(10):8880, doi:10.2903/j.efsa.2024.8880, Re-evaluation of silicon dioxide (E 551) for infants below 16 weeks and follow-up for all population groups).
What is E551?
E551 is the E number for Silicon dioxide, an additive. Open Food Facts tags it en:e551.
Next to it on the label
The E numbers either side of E551 in our table, then the closest additives of the same kind by number.
- Calcium ferrocyanide (E538), no risk identified
- Sodium aluminium phosphate (E541), moderate risk, flagged for young children
- Calcium silicate (E552), moderate risk
- Magnesium silicates / talc (E553), moderate risk
- Sodium aluminium silicate (E554), high risk, flagged for young children
- Potassium aluminium silicate (E555), moderate risk, flagged for young children