The fact that the bag as not been open will not ensure that the flour is still okay to use. There is a window of a few months past the BB when the product is still okay, it is dependent on how it was stored. If stored cold or frozen the flour can be okay for a long time after the BB. If you are unsure, try the hot water test. Put a few tablespoons of flour into boiling water, stir well and sniff. If product is rancid the smell will come out with the steam.
I have not opened the flour bag, but it is past the best before date, is it still okay to use?
Category: PRODUCT INFORMATION FOR FLOURS AND CEREALS