Investigations rat out Fake Ingredient in Cheese

(CBS NEWS) The grated cheese you've been sprinkling on your spaghetti may not be what you think it is. In fact, you may be eating a derivative of wood pulp.

Bloomberg News reports that it hired an independent laboratory to test store-bought grated cheese for wood pulp content. They said a small amount -- two to four percent -- is allowed in grated cheese as an additive to keep the product from clumping. It's listed on ingredient labels as cellulose. Cellulose is recognized as safe by the U.S. Food and Drug Administration, and is used in a wide variety of packaged food products.

The investigation turned up some surprising findings: Essential Everyday 100% Grated Parmesan Cheese from Jewel-Osco was actually 8.8 percent cellulose, Wal-Mart Stores Inc.'s Great Value 100% Grated Parmesan Cheese tallied 7.8 percent, and Kraft cheese contained 3.8 percent (within acceptable limits).

Even Whole Foods' 365 brand, the store's natural and organic product line, didn't list cellulose as an ingredient on the label but it still tested at 0.3 percent.

Whole Foods and some of the other cheese sellers in question responded saying they question the testing methods and told Bloomberg they're looking into the findings.

The FDA is investigating an additional cheese maker, rural Pennsylvania company Castle Cheese, for fraud. In a July 2013 letter to the company, the FDA wrote: "Your product labels declare that the products are parmesan cheese or romanocheese, but they are in fact a mixture of trimmings of various cheeses and otheringredients. In addition, your parmesan cheese products do not contain any parmesan cheese."

Castle supplies thousands of retail stores in 30 states with their product, Bloomberg reported, adding that the company's president, Michelle Myrter, is set to plead guilty this month to criminal charges. She faces up to a year in prison and a $100,000 fine.

Consumers may want to stick with block cheese and invest in a grater until further notice.