Vacuum sealing was originally used by food packing companies in the 1940’s as a way to prolong the shelf life. The principle is to evacuate the air from the bag or container so there’s little oxygen inside, in that case, there’s no condition for microorganism growth and reproduction. It’s not only as a way to prolong the shelf life but also to keep original flavor. And it can also prevent ”freezer burn”. It’s a convenient and economical way for households to preserve food with its original flavor.