Just discovered flour mites inside and all over the top of a bag of flour I only bought a few months ago. Am cleaning the cupboard out with disinfectant and chucking all my flour away. Anyway, it's such a waste and annoying, so I googled it. Apparently the flour mite eggs are already in the flour which makes me feel really sick. However, I really want to eat puddings and cake so after googling I've just put the new small bag of flour I've bought in a plastic bag and am going to freeze it for seven days which apparently kills the eggs. (ugh). You can apparently keep it in the freezer and just spoon out what you want because it has no moisture in it and just stays like normal flour.
Fingers crossed.