Here in the tropics you can find tiny bugs, the size of a pin prick, in dry goods that you keep for a while. e.g. rice, lentils etc. They get to work eating the food you bought. They leave powder behind, which is one tell tale sign. I guess there are all sorts of tiny bugs, depending on the product.
I didn’t think they would be in my German tea that I bought in Germany, and I was eking it out as I can’t normally buy it – but after a year I found they had eaten it too.
The solution appears to be to eat what you bought soon after purchase, or store it in the freezer until you are ready to eat. They can keep warm living inside rice etc. apparently, but won’t come out of the grain because it is too cold.
I have lost grains, nuts and now tea to these bugs, so now usually only buy what I will soon consume.