Flour weevils do not harm people, animals or furnishings though they can infest and damage stored grains and seeds. Fortunately, freezing flour for a minimum of 72 hours can kill weevil eggs, pupae and larvae and prevent an infestation.
To freeze flour in its original paper package, the entire sack must be placed into a heavy, food-grade plastic bag, sealed with the excess air removed, and put into the freezer. After three days, the bag can be moved to a cool, dark place in a food-grade plastic container with a tight-fitting lid. Flour can also be permanently stored in the freezer or refrigerator to keep it from becoming rancid.