Powdered cellulose is purified, powdered plant fibre derived from wood pulp or cotton linters, designated E460(ii) in the European additive system. Chemically it is simply cellulose, the structural carbohydrate of plant cell walls, cleaned and milled to a fine white powder. In food it functions as a bulking agent, anticaking agent, and fibre source: it keeps grated cheese from clumping, adds bulk to low-calorie foods, stabilises foams, and boosts the fibre content of baked goods and cereals. Because humans cannot digest cellulose, it contributes essentially no calories while providing the physiological effects of insoluble fibre. It is considered safe, being chemically identical to the fibre in vegetables, though its presence on labels sometimes surprises consumers who do not expect wood-derived ingredients in their cheese. Functionally, it is plant fibre in its purest form.