There's good news and bad news about the revelation that a supposed 100-percent Parmesan cheese was adulterated with cellulose—a filler often made from wood pulp.
First the good: Eating cellulose won't kill you. There are no known harmful side effects from adding it to food, and it's completely legal.
"Cellulose is a non-digestible plant fiber, and we actually happen to need non-digestible vegetable fiber in our food—that's why people eat bran flakes and psyllium husks," says Jeff Potter, author of Cooking for Geeks.
And though it makes for more sensational headlines, it's not quite accurate to claim that something made with cellulose is part "wood pulp," as implied in a rather breathless Bloomberg News headline. ("The Parmesan Cheese You Sprinkle on Your Penne Could Be Wood") Companies that manufacture cellulose create it from a variety of sources, from wood pulp to asparagus.
"Basically anything with plant stuff in it," Potter says.
So could part of the faux-Parmesan cheese you eat once have had a tire-swing hanging from it? Sure. (We say faux-Parm because in the U.S., cheese only has to be made of cow's milk and meet a certain fat and water content, whereas really real Parmigiano-Reggiano only comes from northern Italy and is made and sold by a strictly controlled group of government-approved cheesemakers.) But it could also have been made in part from a crateful of apples that didn't make it onto supermarket shelves, or corn husks, or any variety of plant matter. It could even have been made from the crate the apples came in. By the time it becomes cellulose, it's pretty much just a tasteless powder whose primary purpose in life is to take up space... It's like an accountant at a rock concert after-party.
It's worth noting, by the way, that the official FDA warning letter to Castle Cheese Inc. lists cellulose and starch as adulterants they discovered, but that they don't mention wood pulp anywhere in the text. Blame easy conflation by an overeager headline writer. We've all done it.
Now here's the bad news about the fake-Parmesan scandal: You've probably been eating cellulose already.
There are a couple main reasons why manufacturers would add cellulose to a food product, and they're big ones. The first is that it saves them a lot of money. Some food products—like real Parmesan cheese—are notoriously expensive. Cellulose, on the other hand, is cheap. So by stretching out a pricy cheese with cellulose, companies get to sell, say, twice as much product for half the expense of making it. (Castle Cheese went further and had the chutzpah to charge even more than most do for real Parmesan made the hard way.)
The second big reason cellulose is a popular additive to food products is that it adds body and mimics the characteristics of more luxurious foods without adding calories or fat.
"It has certain physical properties that allow manufacturers to cut out other ingredients to make things like pancake syrup or low-fat cookies or low-fat ice-creams that have the mouthfeel of ice-creams with regular levels of fat," Potter says.
