Can you pasteurize flour at home?
In principle, I don't see why you couldn't take the flour to safe temperatures just like any other food. You'd have to reach temperatures which break down proteins, something like 165 F or 75 C should be sufficient (it's good enough for meat). 

This will break down the proteins in the flour too, so I would expect it to behave like standard browned flour (although browned flour is taken to higher temperatures than that). It won't be suitable for making doughs and batters, or at least will perform much worse. You can use it for not-completely-white roux, or for fermenting bosa, or any other standard use of preheated flour.