Parmesan cheese

In February, Bloomberg News tested store-bought grated cheeses for cellulose, revealing that all of the cheeses — called 100% Grated Parmesan Cheese — tested contained the anti-clumping additive made of wood pulp.

While cellulose is a safe additive, an acceptable level is 2% to 4%, according to cheese technologist Dean Sommer. Cheese makers often mix in higher levels of the wood pulp when making cheese because it is less expensive than pure Parmesan.