To ensure the good looks of the Oscar Mayer Wieners it packages in Europe, Campofrio Alimentacion SA (www.campofrio.es), Madrid, Spain, uses a vacuum thermoformed structure called Amcor OptiSur.
Packaging is supplied by Amcor Flexibles (www.amcor.com), Gloucester, England. DuPont Surlyn resin from E. I. du Pont de Nemours and Co. (www.dupont.com), Wilmington, Del., is used to form the packages.
The resin is stiffer and glossier than polyethylene, and it enables a secondary sealing process in which heat is applied to the closed vacuum pack. The heat and strength of the vacuum create a second seal in all parts of the package that don't contain product.
Thanks to the secondary seal, liquids do not flow freely inside the package. The result is a clean presentation for the product and the elimination of potential bacterial growth in the liquid. The secondary seal also reduces the chance of punctures, which can lead to vacuum loss, product contamination and leaky packages.