Do instant or boxed potatoes ever go bad just sitting on the shelf?

No, instant or boxed potatoes do not go bad just sitting on the shelf. They have a long shelf life because they are dehydrated and contain preservatives. Dehydration removes most of the water from the potatoes, which prevents the growth of bacteria. The preservatives, such as sodium metabisulfite and potassium sorbate, further inhibit the growth of bacteria and mold.

While instant or boxed potatoes will not go bad in the traditional sense, they can lose their flavor and nutritional value over time. The best quality is usually within 12 to 18 months of the production date. To maintain their best flavor and nutritional value, store instant or boxed potatoes in a cool, dry place.