Portola Packaging announced in March it developed a new Steri-Shield linerless plug closure technology for aseptic beverage packages. The category has traditionally used closures with thermoplastic elastomer (TPE) or foil liners to achieve seal integrity for both low- and high-acid beverages. By eliminating the liners, the plug design helps minimize package cost and contribute to material source reduction. The aseptic linerless plug closures are compression-molded using a proprietary resin blend which includes high-density polyethylene. The end result is a lightweight closure which does not fail during the sterilization and/or distribution process. Additionally, the structure can withstand an aseptic sterilization environment of up to 140 degrees Fahrenheit.