Heat treatment is usually related to the need of feed hygienisation in order to eliminate preventively pathogenic microorganisms.
The feed in the meal form is subjected to heat treatments, including steam.
Heat treatments can be carried out continuously or by batches. The principle consists in treating the feed with a temperature of 85°C for several minutes under the steam action. Unlike conditioners of pellet mill, steam can be incorporated in several spots and treatment devices are systematically insulated.
In continuous systems, the residence time distribution of particles must be kept under control so that all particles undergo the expected treatment. These treatments result in a “wet pelletizing” by bonding fine particles of the largest particles under the steam action.
Other treatments are possible, such as extrusion, but they found few applications in the animal feed field, except for petfood plant and fishfood plant that use more likely this feed technology.