In 2012, FDA agents raided a cheese factory in rural Pennsylvania. The factory belonged to Castle Cheese Inc. Thanks to a tip, the agents had reason to believe the company was contaminating its supposedly 100% real parmesan with cut-rate substitutes. Their investigation turned up evidence that Castle was indeed doctoring their cheese. Their flagship parmesan brand, it turns out, was filled with things like wood pulp. In some cases, the ‘cheese’ barely contained any cheese at all.
Sadly, this gross finding was not an isolated incident.
Records of previous FDA investigations show a clear pattern of parmesan cheese suppliers cutting their product with fillers. Common ingredients included cellulose made from wood pulp and cheddar cheese, which is much cheaper than parmesan.
Cellulose is considered by the FDA to be a safe food additive at levels around two to four percent. However, common consumer brands of parmesan cheese often contain levels around the eight percent mark.