Abstract: An aseptic package of a material susceptible to bacterial or viral infection utilizes a film or sheet of a plastic packaging material having a biocidal agent dissolved or dispersed therein. The biocidal agent comprises 10,10-oxybisphenoxarsine or a biocidal derivative or analog thereof, in an amount sufficient to inhibit biocidal activity in the contents of the package. The biocidal agent is present in solution in or in combination with a plasticizer for the plastic sheet or film in an amount from 0.001 to 5.0% by weight of the plastic. The sheet or film is a hydrocarbon-based material, such as a polyalkylene resin or polyolefin, e.g., polyethylene or polypropylene. The biocidal agent is present in solution in or in combination with a plasticizer for the plastic sheet or film. The enclosed material may be an organic product, such as a food or a plant or may be formed in the shape of a dispensible liner for bath tubs.