A process line for the production of freeze-dried particles under closed conditions is provided, the process line comprising a freeze-dryer (100) for the bulkware production of freeze-dried particles under closed conditions, the freeze-dryer (100) comprising a rotary drum (104, 302) for receiving the frozen particles, and a stationary vacuum chamber (102) housing the rotary drum (104, 302), wherein for the production of the particles under closed conditions the vacuum chamber (102) is adapted for closed operation during processing of the particles. The drum (104, 302) is in open communication with the vacuum chamber (102) and at least one transfer section (106, 108) is provided for a product transfer between a separate device of the process line and the freeze-dryer (100), the freeze-dryer (100) and the transfer section (106, 108) being separately adapted for closed operation, wherein the transfer section (106, 108) comprises a temperature-controllable inner wall surface.