A shelf-stable concentrated antimicrobial composition comprising at least one cyclic carboxylic acid and/or salt thereof in an amount from about 2 wt. % to about 4 wt. %； at least one anionic surfactant and/or salt thereof in an amount from about 22 wt. % to about 32 wt %； at least one non-surfactant strong acid (i.e. having a pKa less than about 2.3) in an amount from about 8 wt. % to about 18 wt. %； and at least one chelating agent in an amount from about 0.1 wt. % to about 2 wt. %. The composition retains at least 90% of its original antimicrobial efficacy after storage for at least five years at room temperature, and is substantially free of additional antimicrobial compounds including hydrogen peroxide, sources of hydrogen peroxide, essential oils, parabens, aldehydes, aldehyde releasing agents, phenols, antiseptic alcohols, biguanides, peroxycarboxylic acids, quaternary ammonium compounds, chlorine compounds, enzymes, and etchants. Also described are methods for using the composition to reduce the microbial load on a surface comprising, optionally, the step of diluting the composition with water and/or an organic solvent and, optionally, adding an additional antimicrobial compound, e.g. hydrogen peroxide, prior to use.
