E551: Silicon Dioxide
Main role: preventing clumping
Also listed as: silica, synthetic amorphous silica
What is E551 (Silicon Dioxide)?
Food additive silicon dioxide is specified synthetic amorphous silica used to improve the flow of powders. Its identity differs from crystalline silica associated with some occupational dust exposures.
What does it do in food?
Its main role is preventing clumping. Mineral ingredients can adjust acidity, firm a food, or keep powders flowing. A technical mineral ingredient does not establish a nutritional dose; use the nutrition declaration to assess amounts per serving.
Food and formulation examples
- Powdered seasonings
- Instant mixes
- Food supplements
These examples describe formulation roles, not a list of unrestricted legal uses. Availability and permitted applications differ by country and food category.
Label names and ingredient questions
Look for E551, E 551, or the ingredient name. Related names and label terms include silica, synthetic amorphous silica. A family code can cover more than one specified form; check the full declaration when the distinction matters.
Inhalation of industrial crystalline silica and eating food-grade amorphous silica are different exposure questions. Particle characteristics and food specifications still matter in evaluating E551.
Is E551 safe?
EFSA’s 2024 assessment found no safety concern for the evaluated food uses, while recommending tighter impurity specifications. EFSA silicon dioxide follow-up (2024).
A label identifies the ingredient but usually not its concentration. Calculating daily intake requires the amount in the food and the quantities eaten.
Authorization and conditions of use
The Great Britain food additive register lists E551 as Silicon dioxide. This is an entry subject to its stated conditions, not unrestricted permission for every food. The record links to the applicable authorization terms. For an EU product, use the European Commission food additive database to check the relevant food category and limits. Other countries may use different names or rules.