Anti-caking agent, also known as anti-caking agent, a kind of food additives to prevent powdered or crystallized form of food (such as flour, rice flour and salt, etc.) aggregating, agglomerating, so as to maintain a free flow. Anti-caking agent has the following features: particle size of 2 ~ 9μ, large surface area (310 ~ 675m2 / g), high specific volume (80 ~ 465kg / m3) and so on, easy adsorb water from food. Some anti-caking agent has a fine porous structure, with its high degree of porosity ,it can adsorb the agglomeration of moisture, to prevent caking gather food.

There are five permitted species of anti-caking agent: potassium ferrocyanide, sodium aluminosilicate, tricalcium phosphate, silica and microcrystalline cellulose.

There are varieties of anti-caking agents, besides the five permitted species in our country, there also exist aluminum, silica, calcium silicate, calcium stearate, magnesium carbonate, magnesium stearate, magnesium, magnesium phosphate, magnesium silicate, kaolin, talc and the like in foreign countries. It is used to prevent sucrose powder, glucose powder, milk powder and other dairy products caking. It can be used alone or in combination with other anti-caking agent compound without the presence of starch. Besides the effect of anti-caking, some also have other effects, such as calcium silicate and kaolin have the function of filter aids, calcium stearate and magnesium stearate have emulsifying effect and so on. Besides the value of ADI is ferrocyanide somewhat limited, the security of other varieties are very good, the value of ADI is  without provisions, but is based on proper development. Japanese regulates D- mannitol is the release agent of gum and caramel class products. The one China allows useing of anti-caking agent is only potassium ferrocyanide[K4Fe (CN) 6 • 3H2O] currently, to prevent salt caking, whose maximum permitted amount is 0.005mg / kg, (ferrous cyanide meter). Its ADI value is 0 ~ 0.25mg / kg. Potassium ferrocyanide is a necessary food additive in table for long-distance transport and storage of salt.