Disinfecting compositions containing hypochlorous acid and acetic acid are useful for treating transient biofilms in or on tissue without harming the natural flora of the tissue. The compositions are useful for treating a variety of types of tissue. Compositions are useful for treating and preventing orally-associated biofilm. Compositions may be provided in mouthwash form, spray form, gel form, cream form, dentifrice form, and may include nanoparticle encapsulated molecules for controlled release.