The grubs that Mandy is referring to could also be the Indian Meal Moth
worms. These gross things hitch a ride with rice, nuts, cereal, cornmeal,
birdseed, dog food and other grains. Once they get in something they eat
the grain or whatever and leave a spider webby type stuff on the walls of
the packaging. Then they cacoon themselves and turn into moths, which in
turn lays eggs, that turn into the grub type worms etc. To get rid of them
you must throw out any suspicious looking grains. Throughly seal any
grains coming into the house and carefully check items before they even
leave the store.
I have found these moths flying around in the store around the grain
aisle. Well I certainly didn't buy any from them. Really gross stuff. I
hope you don't have these but if you do, pitch your stuff.