Microparticles include a matrix of an encapsulating material, in which are dispersed particles of a low melting point fat and a bioactive material, such as one or more probiotic bacteria. The microparticles are formed by preparing an emulsion of melted low melting point fat in an aqueous mixture of the encapsulating material, cooling the emulsion below the melting point of the low melting point fat, dispersing the bioactive material in the emulsion and spray drying the emulsion. The particles of solid low melting point fat are believed to protect the bioactive material from heat damage during the spray drying process.