A vacuum packaging machine includes a vacuum chamber and a sealing mechanism within the chamber. A product-filled package can be supported within the chamber with its open end disposed between sealing bars of a sealing mechanism. At least one of the sealing bars is continuously heated including as the package is placed within the chamber, as a vacuum is drawn in the chamber, as the sealing bars are closed around the open end of the package and as the package is removed after sealing is complete.