The flour sacks I get have a paper upc label on the fabric that comes off easily. Also to prevent weavels you can either put the flour in the freezer for a few days & if you don't have freezer space, put a few bay leaves in it. I use both of these methods & have never had weavels no matter how long I have had stored flour. I put bay leaves in anything that has a flour base to it like pasta & even oat & corn meal. I did test this several years ago by buying two small bags of flour. One I put a bay leaf in it & the other not. Set them side by side on a shelf touching each other. The one without the bay leaf got weavels & the other did not. So I do know this works.