An acidic aqueous composition having a pH of from 1 to 4, for elimination of spores of spore forming bacteria, comprises from 100 to 2000 ppm dissolved chlorine dioxide, and a surfactant system having a wetting effect and a spore solubilising effect. The surfactant system comprises at least two hydrocarbon ionic surfactants stable for oxidation at the acidic pH, of which at least two surfactants have a difference in hydrocarbon chain length of at least four carbon atoms and are anionic surfactants at a pH of from 1 to 4, selected from the group consisting of soluble salts of alkyl sulphates, alkyl sulphonates, alkyl aryl sulphonates, and aryl sulphonates, having between 6 and 25 carbon atoms in the alkyl chains. Methods of eliminating spores of spore forming bacteria from the genus Clostridium on a surface comprise contacting the surface with an effective amount of the composition.
