The present invention relates to the field of frozen or dry compositions for prokaryotes, in particular fermentative bacteria such as lactic acid bacteria, a method for preparing frozen or dry prokaryotic compositions and compositions which may be prepared by said method. The cells in a cell concentrate are activated by allowing them to ferment a carbohydrate, before freezing and/or drying to provide a product. The hydrophobicity of the cell surface increases during activation, and this has been found to increase the storage stability of the product.