[emacsen]

It's a combination of factors. First, as the other replies mentioned, there are preservatives and stabilizers in supermarket breads.

Also, any bread in a plastic bag won't go stale as quickly, but it can grow mold due to the presence of moisture, but factory bread contains things like calcium propionate that inhibit mold growth.

Bread without preservatives and kept out of a plastic bag will go stale in a short time (a couple of days maybe).

[Fire-Dragon-DoL]

It depends on the flour. A friend of mine baked bread, but he also made the flour (and everything really. Not for mass production). His bread took a week to go stale. It was also amazing to eat (not an expert).

He grew his own wheat and had some very specific requirements when making the flour (he didn't own the grind, but he was friend with the owner).

That's all I know. Of course no GMO.

[wrycoder]

Stand it on the cut edge and cover it with a thin dish towel.