It's completely safe to eat. It's mould growing on the bread. As far as I'm aware, mould is not poisonous. It may upset the stomach a little but it certainly won't cause any lasting problems.
People are grossed out by too many things these days. I probably wouldn't eat the bread but the idea of it doesn't freak me out. When a man is hungry, he must eat. When there is nothing else to eat, eat what's available. Simple as that.
I bet most of the people who are completely grossed out by the question have fridges half-filled with products that have expired/are going to expire soon because they felt like having some but didn't finish it. And people wonder why there's a food crisis... :|