Method for operating food mill

The invention provides a method for operating a food mill, which mills various kinds of foodstuffs that have been heated and softened using superheated steam by passing same through a strainer while limiting cell destruction as much as possible and which is ideal, for example, for continuous production, etc. of a puree in which the original color, fragrance, taste, and nutritional value of the foodstuff has been preserved as such, and an automatic food mill. The starting material foodstuff is crushed or ground by the shearing force that is produced between the upper and lower mortars by the generation of a difference in rotation speeds between the upper and lower mortars, and the crushed starting material foodstuff is separated into strained material and residue and collected in a strained material-collecting section and a residue-collecting section, respectively, by means of the centrifugal force generated by the rotation of the lower mortar and utilizing the concave conical surface of the lower mortar.