Our grandparents and parents often canned foods based on times of harvest or other considerations like preserving wild game or meat from farm animals. A few foods like corn or apples could also be dried and thus preserved for future use. It was only in the last half of the twentieth century that large home deep freezes became common and their use significantly reduced the amount of foods canned or dried at home. Since that time commercial food producers started using shrink-wrap, heat sealing and then vacuum sealing and nitrogen atmosphere environments in polymer packaging both to preserve the products awaiting purchase and to improve their appearance and to mechanize food production and reduce human labor/cost. Yet through it all a short trip through your local supermarket will make you smile as you realize that we still use all methods named above for food preservation and marketing advantage even today.