Methods and systems for generating steam vapor having low zeta potential mineral crystals capable of disinfecting surfaces and objects upon an exposure period to the steam vapor. The steam vapor system comprises an aqueous liquid source having a threshold concentration of selected minerals, a liquid treatment system for treating the aqueous source liquid to produce treated liquid having an enhanced concentration of low zeta potential mineral crystals, and a steam vapor generator for producing steam vapor from the treated liquid, whereby the steam vapor has a higher concentration of low zeta potential mineral crystals than the aqueous liquid source. The steam vapor generated from the treated liquid is applied to surfaces or objects.