A continuous system for the heat treatment of divided solids, combined with a gas-solid reaction for the debacterization especially of food products, such as herbs, spices, powders. The system includes a unit for supplying the product a debacterization unit having a fluidized bed moving the particles by means of vibration associated with a feed of steam or other gas, a cooling drying unit, and a packaging unit. The debacterization unit comprises a vibro-fluidized stepped bed for enabling the transport of the product that is carried out successively according to a generally horizontal first transport phase, and at least one second vertical transport phase during which steam or another gas is injected, acting in such a way as to decontaminate the product as it moves from the horizontal phase to the vertical phase and to the following horizontal phase.