Silicon dioxide (Silica)

Silicon dioxide, commonly referred to as silica, is the same mineral compound that forms sand and quartz. In food-grade form (E551), it is an amorphous, white powder used as an anti-caking agent in powdered products such as salt, spices, dried soups, powdered creamers, cake mixes, and seasoning blends. Very small concentrations prevent clumping by absorbing surface moisture and coating powder particles to keep them free-flowing during storage and packaging.

JECFA evaluated food-grade silicon dioxide in 1974 and did not establish a numerical ADI, confirming no safety concern at any realistic dietary exposure. Food-grade amorphous silica is distinct from crystalline forms such as quartz and cristobalite, which are associated with respiratory harm when inhaled occupationally. The amorphous form used as a food additive is biologically inert and does not accumulate in the body.

Silicon dioxide is approved globally — EU (E551), United States (GRAS), Japan, Korea, and elsewhere. It is used in extremely small concentrations, typically less than 2% of a product. There is no evidence of any health concern from the quantities present in food. Consumers may see it listed in powdered food products and can consider it one of the most uncontroversial anti-caking agents available.