Process of blow molding a food and beverage container with a melt phase polyester layer

A process for forming a container for holding contents, comprising the steps of:

• polymerizing in the molten phase, but not the solid phase to form a melt phase polymerized thermoplastic polyester, said polyester thereby retaining therein undesirable substances intrinsic to the polymerization reaction, wherein said substances are products of the polymerization reaction including unreacted monomers, oligomers and acetaldehyde, said acetaldehyde being present in excess of 2 ppm, whereby the polymerization is carried out to a polymerization level leaving residual amounts of said undesirable substances therein in an amount capable of migrating from said polyester into said contents when said contents are in contact with said polyester;
• combining said melt phase polymerized polyester containing said residual undesirable substances with a protective substrate and forming a composite having a layer comprising said polyester and a layer comprising said protective substrate, wherein said protective substrate is formed from a material which limits the migration of said undesirable substances form said polyester into said contents;
• forming a preform having said layer comprising said melt phase polymerized polyester and said layer comprising said protective substrate;
• and
• blow molding said preform into said container, wherein said protective substrate is positioned for contact with said contents.