Abstract: A process for supply of low concentrations of biologically active materials to base materials such as a processed foodstuff or an animal food, in which the biologically active material is slurried in an inert carrier, where it is insoluble, to form a homogeneous suspension, after which the suspension is applied to the base material by means of a device converting the suspension to an easily applicable form, the suspension coating the surface of the base material in an even layer. The suspension is maintained homogeneous by stirring and at an even temperature before being applied to the base material at such a rate than an even and predetermined concentration of the biologically active material is obtained per weight unit distributed on the surface of the base material.