Quat-free surface treatment powders comprising a peroxide source, an acyl group donor and an alkalinity source are used to disinfect and/or sanitize hard surfaces. The surface treatment powders can be applied to a hard surface and left there for a period of time. The surface treatment powders are ambient moisture activated, which means that they can generate peracetic acid when a portion or all of the powder that is on the hard surface adsorbs water from the atmosphere. In addition or alternatively, the surface treatment powders are activated, i.e., generate peracetic acid through the incidental or purposeful addition of liquid thereto.