A method for the reduction and/or removal of pathogenic agents and microorganisms contained in solids, comprising the steps of purification of the starting material to dispose of materials that combine a great size and extreme hardness and malleability； and the adjustment of the humidity degree of the material obtained in step of purification, and the grinding and heating of the material obtained in the step of adjusting the humidity, where the grinding and heating are carried out simultaneously by subjecting the material to a high pressure while at the same time its temperature is increased by means of an increase in the pressure on the material and the friction caused between the material and the grinding means. And A machine to carry out the method, comprising a front chamber for the entrance of the material； a contiguous rear chamber associated with the entrance chamber, by means of which the processed material is expelled； said contiguous rear chamber containing a grinding means that rotates when it is actuated by an engine； and a piston that enters into the front chamber running along said chamber into the rear chamber until it reaches a grinding means, where the grinding means consists of a solid, hard and heavy cylinder associated with a transverse axis, said cylinder being provided with a set of longitudinal slots from base to base that form edges with the cylinder surface.
