While the flour miller takes steps to ensure the flour is bug free and devoid of any insect eggs, nothing is 100% so there is always a possibility that there can be some viable eggs in the flour. When they hatch they will be larvae and the flour will be "wormy", then they mature into adults and you have "buggy" flour, soon to be followed by the laying of eggs and a repeat of the cycle. This can all take place in as little as a month. So, at the very least, you should take steps to ensure the flour is not infested from the outside of the package, this means putting it into a plastic or metal container, no need to be air tight, bust bug tight. Flour does change during storage, it oxidizes, meaning that it gets stronger. This may not be a good thing as it can result in excessive dough memory/snap-back during the forming operation. For this reason, we suggest storing the flour in the fridge if at all possible. If you plan to store it for an extended length of time we suggest first freezing the flour for 45-days or more, then storing it in the fridge.
Tom Lehmann/The Dough Doctor