Food or feed processors (16, 16a) include an elongated processor barrel (38) presenting an inner surface (44) with a central body or tube (60) within the barrel (38) and presenting an outer surface (62). The surfaces (38, 62) define an elongated annular processing region (70). The barrel (38) and tube (60) are steam heated by means of apparatus (52, 66). A rotatable processing element (72) is also located within the region (70). The element (72) has a plurality of vanes (88, 104), which scrape the surfaces (44, 62) to prevent buildup of material on these surfaces.