Nothing is bear proof, just resistant. Canisters work the best of course, due to their not giving rewards.

But...if hiking in an area with no grizzlies and no habiuated black bears (ones who have learned to be aggressive in stealing food) Ursack bags shine. Outside of California in the Sierras, there is often no official rules in parks or forests on what is and isn't allowed. Most park websites DO have rules posted under the hiking and backpacking section. NF's though tend to often have no rules.