Grumble Grumble Grumble
Are you looking for episodes, or just the sound? (The stomach growl is such a common sound effect, everyone appears to use the same canned sound recording...)
One's that I've recently seen...
'Lucky Star OVA' (the scene where the girls are lost while hiking...)
'One Piece' (first episode of the 2nd season, after the girl Apis is rescued from the lost boat at sea...)