Go buy a small bottle at the grocery store and compare the smell to the stuff in the boxes. As far as the OP goes, cooking oil takes on tastes of what you fry in iteven if it isn't rancid it can impart a bad flavor after it is used a couple of times. If you are asking the question, and aren't sure about the appearance, don't use it, it most likely won't make anyone sick from bacteria because of the high temps it is used at, but it won't make your food taste good either.