The present invention provides a process for the preparation of freeze dried microorganism composition, comprising the step of (i) subjecting a frozen composition comprising micro-organisms to a drying pressure of from 133 Pa [1000 mT] to 338 Pa [2540 mT] such that at the drying pressure the frozen composition is dried by sublimation of water present in the frozen composition to provide a freeze dried composition comprising the micro-organisms.
