The present application relates to a fermented milk or yoghurt powder which contains very high contents of S. thermophilus and L. bulgaricus, and which exhibits exceptional storage capacities. In the powder according to the invention, no substantial loss of live S. thermophilus and L. bulgaricus is observed after four months of storage at 20° C. The powder according to the invention has microbiological characteristics such that it itself corresponds to the name yoghurt or fermented milk.