Fuente: WIPO "apiculture" Patent 544366 The use of a formulation comprising at least one volatile fraction (VF) of a plant extract, said plant extract is obtained by water extraction and said volatile fraction being prepared by steam distillation of said plant extract under a pressure lower than atmospheric pressure and at a bath temperature not exceeding 38 degrees C; to sustain viability of as much as 107 cells/ml of at least one microorganism for at least two months at room temperature, with the proviso that said microorganism is not Escherichia coli strain BU-230-98 ATCC Deposit No. 202226 (DSM 12799). Also disclosed are dispensers for said formulation and methods of using said formulation.