I expect she was describing something else. Bugs, especially things like weevils [1] tend to lay microsized eggs in grains of all sort. Even when hermetically sealed they'll be able to hatch and thrive. I tend to buy relatively large quantities of things like rice, flour, etc and finding bugs in hermetically sealed bags after some lengthy time is not uncommon.
It's not bugs getting into your food from the outside, but being packaged into your food! If you don't have bugs it means they've been killed in some way, and one of the easiest to do that is chemical. Incidentally, weevils (the most common) are harmless and tasteless to consume. It just means a bit of extra protein in your food!