something i learned years ago when i sold tupperware. it's just about the best thing you can use to keep bugs out of your stuff ... but if what you put in already has bugs, it can't work. it will help to keep them from spreading to your other foods, though, which is better than nothing.
soooooo ... you have to check your foods for critters before you store them - not matter which brand you use. pasta is fairly easy to check. flour, sugar and similar things can be sifted before storage. dark colored things are a bit tougher to check, but it's worth the effort if you live in a "buggy" area.