The present invention relates to an apparatus (1) suitable for use in the treatment of tubers (22) comprising a vessel (2) having an endless conveyor means (3) for conveying said tubers (22) through a water holding zone (10) between a loading station (23) and a discharge station (27). Water heading and circulation means (28, 29) are provided for heading and circulating the water at a temperature from 50 to 65 DEG C. A conveyor drive control means (20, 32) is provided for controlling the speed of said conveyor means (3) so as to determine the transit time between said loading and discharge stations (23,27) thereby determining the tuber residence time in said water holding zone 10. The conveyor means (3) has tuber support and retaining means (14-19) of generally open-work structural form so as to permit water flow therethrough to substantially all sides of said tubers (22), said conveyor means (3) being further formed and arranged so as to tumble and/or roll said tubers (22) at least along a substantial part of said conveyor path portion. The invention also provides a method of treatment of potato blackleg in tubers (22) comprising the steps of size-grading the tubers (22), bringing them to a thermal treatment zone (10), introducing them into a body of thermal treatment fluid at a temperature of 50 to 65 DEG C for a period of time sufficient to substantially kill the blackleg organism without significantly damaging the tuber tissue, and cooling the tubers (22).
