A system includes a cold plasma applicator configured to couple directly to a container, wherein the cold plasma applicator is configured to generate a cold plasma within the container. A method includes operating a cold plasma applicator to generate a cold plasma to treat contents within a container, wherein the cold plasma applicator is configured to directly couple to the container, or the cold plasma applicator comprises a varying geometry application surface having a plurality of protruding electrode portions spaced apart from one another to define a plurality of intermediate recessed portions, or a combination thereof.