Moldy bread smell but no mold? I have Nickles brand multigrain bread. 2 slices of it are just stale. The others though smell moldy but I don't see any mold whatsoever on any of the slices. They taste strange too. This I know because I ate one of them to releive my heartburn last night.

So why would my bread smell moldy when I don't see any mold? Usually if it is dry and has no mold it just smells and tastes like stale bread.
The mold is growing and producing that smell.  Mold spores form on ALL bread when it is exposed to air.  That's why it takes a few days for the mold to actually be visible. The mold doesn't just instantly grow, it "forms" over a few days and when enough of it accumulates, you see it.

Bread with preservatives, have a longer shelf life because they contain a mold inhibitor.  After the expiration date on the bread, that "inhibitor" will no longer keep the mold from "blooming" and it will rapidly appear and multiply.

If the bread smells bad/moldy, DO NOT eat it!  You can get sick on moldy bread.

My daughter(we) did a Science Fair Project on Mold Growth in Bread and this was some of the information we found.

Hope this answers your question.

An added note:  Storing sealed bread in the Refrigerator does NOT extend the expiration date.