Methods of eliminating spores

An acidic aqueous composition having a pH of from 1 to 4, for elimination of spores of spore forming bacteria, comprising from 100 to 2000 ppm dissolved chlorine dioxide, and a surfactant system having a wetting effect and a spore solubilising effect, wherein the surfactant system comprises at least two hydrocarbon ionic surfactants stable against oxidation at the acidic pH, of which at least two surfactants have a difference in hydrocarbon chain length of at least four carbon atoms, wherein said ionic surfactants in the surfactant system are anionic surfactants at a pH of from 1 to 4, and wherein the anionic surfactants are selected from the group consisting of soluble sodium salts of alkyl-diphenyloxide-disulphonates and alkyl-phenyl/diphenylsulphonates, with 6 to 19 carbon atoms in the alkyl chains, and at least one of the anionic surfactants is selected from the group consisting of mono- and dihexadecyl disulphonated diphenyl oxide disodium salts and decyl(sulphophenoxy)-disodium salts, and wherein the two or more surfactants are present in an amount of from about 0.01 to about 2% (v/v).