I store my whole wheat flour in Tupperware containers which are airtight, right? Wrong ! I strongly suspect the flour I purchased from a large market was already infested. I am so grossed out about this. The flour was not old.
Should I have to freeze all my flour as soon I get home from the market? The thought of even baking with dead bugs is repulsive.

The pantry moth (Indian meal moth) is a tiny moth very common in floury foods, dog food, bird seed, and so on. They leave little white larvae and then a brownish case when the larvae hatch.

They can get right through plastic unless it's hard plastic with a super sealed top like OXO. You can't blame it on a particular store, because once you get them they are almost impossible to get rid of.
But I did... took almost forever.

YES. The grain moth has been a problem in my neighbors house. She figured it would be safer if she got the organic bulk, rather than the supermarket flours. I told her that even when grains are local and organic (those ARE the BEST, because grains have the highest amount of pesticides... about as much as the toxins "the meat" eats). Organic is about natural pest control and pesticide free foods. Local is great because "the traveling pests" have less of a chance of getting into the "shipped packaging". Big markets have things shipped from afar ( other states/countries), and most of the time carry stow aways! They fly and crawl. They CAN get into other market foods that are not vacuum-sealed, especially/in-particularly GRAINS. Grain bugs, pantry beetles are PESTS... PERIOD!! Sometimes you may find an occasional bug in the fice or beans or flour, which is why you MUST CHECK the grain and preferably wash it before storage. If it is flour it must be checked and then stored in your freezer for a FULL 24hours, THEN store in a vacumed sealed Jar (like the mason). You can find Large starage jars at the health food markets ( call around, ask for jars that can carry the size of a gallon or a pound to 4-5 pounds plus of flour) before use. My jars coast $4.43ea. I went to the dollar store and got many gallon and quart sized jars for my flours and beans. DOUBLE OR TRIPPLE LAYER A SHEET OF SERAN WRAP (the bugs don't like that stuff), TO USE AS A SEALENT OVER THE JARS, cut around the jar after asuring a TIGHT fit.I suggested that she freeze EVERY bag, after checking the item,store and keep the jar shut any second you are not scooping,etc.