UK here, our bread bags are sealed with a piece of tape. It can't be used to reseal the bag, but there's enough excess length on the bags that you can just tie them in a knot to reseal them

Usually sliced bread is sealed with a bit of tape that has the best before date printed on it. Although it still only keeps for days rather than weeks, at a push you can probably get about a week before mould starts growing on it. Then real bread will probably start going stale by the next day.

So, america?