When it comes to food packaging, there are a variety of different materials that can be used for dog food bags. However, the most common type of material used is polyethylene terephthalate (PET). PET is a strong and durable plastic that is resistant to both moisture and oxygen. This makes it an ideal material for storing food, as it will help to keep the food fresh for longer. Additionally, PET is also recyclable, so it is a more environmentally friendly option than other types of plastics.