Lidding film, also known as tray lidding film or heat seal lidding film, can be made from a couple of different types of materials including PET, foil, paper, etc. These materials have various strengths and weaknesses when it comes to protecting food products. It’s important to consider how the package will be stored, and if it’s necessary to be frozen or heated. Food safety is critical, so the right film structure for the right food type is critical.