Ultraviolet light stabilized antimicrobial compositions are formed from (A) and (B). (A) is (I) a solid-state microbiocidal compound having at least one bromine atom in the molecule; (II) an aqueous solution or slurry of (I); (III) is a concentrated aqueous antimicrobial composition having a dissolved active bromine content derived from (i) BrCl or BrCl and Br2 and (ii) overbased alkali metal sulfamate and/or sulfamic acid, alkali metal base, and water, (IV) solids made by dewatering a composition of (III). (B) is a ultraviolet light degradation-inhibiting amount of up to one part by weight of ascorbic acid, dehydroascorbic acid and/or an edible water-soluble salt/ester thereof per part by weight of bromine in the selected antimicrobial composition. Preparation and uses of such compositions are described. Methods of controlling contamination of seafood and seafood products by pathogens are also described.