The present application relates to an inoculum that is particularly suitable for the direct inoculation of at least one stran of Bifidobacterium animalis ssp. lactis in a dairy substrate, for the conversion of said dairy substrate into a fermented dairy product. This inoculum comprises, in mixture or in collection form, the L-cysteine base and at least one strain of B. animalis lactis. Said cysteine and said at least one strain of B. animalis lactis are each contained in, or in the form of frozen and/or lyophilizate granules. Advantageously, said cysteine is incorporated within the same granules or the same lyophilizate as the cells of B. animalis lactis.