OldGuy: freeze rice, beans, flour and such when you bring it home. Let it chill for a week, then put it into buckets with some silica gel packets and seal tightly. I keep several hundred pounds of each and after learning this trick, havent had any issues with bugs.
Another thought: For coarse products like beans and rice, toss in a half a cup of diatomaceous earth, cap and shake well. Used or not, shake the container every month or so to mix it up a bit. As you use the product rinse it well to get the DE off. FYI, DE has amazingly sharp edges (check it out under a microscope!) and basically cuts any emergent bugs to ribbons within a day or two. Harmless to people too, but it is gritty which is why you should rinse it off before cooking.
"Give me an underground laboratory, a half a dozen atom smashers, and a beautiful girl in a diaphanous veil waiting to be turned into a chimpanzee, and I care NOT who writes this nations laws"!