The present invention is directed to compositions and methods which utilize a first antimicrobial compound (i.e., chitosan, tannic acid, or mixtures thereof) in combination with a second antimicrobial compound (preferably benzoate, sorbate, EDTA, or mixtures thereof) to inhibit the growth of microorganisms in food products and especially in beverages. The present invention is also directed to cold fill compositions and cold fill methods using chitosan alone or in combination with the second antimicrobial compound (preferably benzoate, sorbate, EDTA, or mixtures thereof), to kill microorganisms and/or inhibit the growth of microorganisms in beverages.