As satisfying as it might feel topping your spaghetti and meatball mountain with a dusting of grated Parm, you might want to resist--or at least start grating it by hand.
Many shakers of pre-grated Parmesan cheese contain wood pulp, which shows up on the ingredients label as “cellulose.” But unfortunately, just because your container doesn’t list it doesn’t mean it isn’t there.
Before you get too worried, there are two things you need to know: the FDA considers cellulose safe, and you’ve been consuming it with no ill effects for years. In other words, wood pulp in your Parmesan is not going to kill you, or even cause any known health issues. However, consumers do have a history of getting into an uproar over it because the FDA had prosecuted companies in the past who incorrectly labeled their products as “100% Parmesan" when there was in fact something else in there.
The controversial ingredient isn't found in this cheese alone, either. It's found in basically any cheese that you pick up at the store that is pre-shredded or pre-grated, including mozzarella, Cheddar, and blends. All it does is prevent those pieces of cheese--which are perfect for easy melting--from clumping together and becoming small blocks of cheese again when they’re in the bag.
Although most companies use cellulose in percentages that clock in under 10% of the container, Castle Cheese did once plead guilty to producing cheese it claimed was Parmesan that contained no actual Parmesan for almost 30 years. These containers were available at superstores like Target.
If you are concerned and want to make sure you’re enjoying only 100% Parmesan, pick up a block of the cheese from the supermarket. You’ll have to grate it by hand, but you can rest assured that there was no cellulose in the container.