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E551Anti-caking agentLow concern
Silicon Dioxide
In plain words
The short version
An amorphous silica powder used as an anti-caking agent in powdered foods, table salt, and spices.
Why it's green
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Safety profile
ADI not specified by JECFA. EFSA re-evaluated in 2018 and noted uncertainty around the nanoparticle fraction; a follow-up review is anticipated. Crystalline forms are not permitted in food. Inhalation of any silica powder is hazardous regardless of form.
The detail
Educational information only. Not medical or dietary advice.