Why You May Want To Think Twice Before Sprinkling Restaurant Parmesan Cheese On Your Pizza

There are a few staple add-ons that you'll almost always find on the table at your favorite pizzeria — crushed red pepper, some oregano, and, of course, grated Parmesan cheese. Parmesan is a salty, rich flavor booster that pairs perfectly with a fresh pizza slice. Whether you're stopping in to a local spot or you're on a mission to try the best pizza in every state, you might want to think twice about picking up that Parm container for one big reason: for quality purposes, it's supposed to be refrigerated, and when it's sitting at your table, it's certainly not.

To be clear, Parmesan cheese doesn't need to be refrigerated for food safety reasons. It's a hard, low-moisture cheese, so it's safe to leave it out at room temperature. This is why you often see it on grocery store shelves rather than in the refrigerator section. The downside is that, at room temperature, Parmesan's quality degrades more quickly, meaning unless that pizzeria Parm was just put out right before you sat down, it probably won't taste as good as you want it to. Once opened, Parmesan cheese can last for a month when properly refrigerated, but when left at room temperature, its quality lessens after about four hours.

As with any dairy product, cheese eventually goes bad — even the robust Parmesan. It isn't the result of refrigeration issues — rather, moisture can eventually get into this cheese, creating a perfect environment for mold growth. On a firm cheese like Parmesan, you can cut out the mold if it's in block form. However, the same can't be said once that cheese is grated.

If you do want a sprinkle of that pizza Parmesan on your slice, just be vigilant. If you notice any mold on the grated cheese, don't use it — and it's best to alert a staff member. Check its color, too, which should be an off white or pale yellow, sometimes golden color. If it looks too dark, it's best to skip it. Finally, give it a whiff. Parmesan should smell nutty and sharp, but it shouldn't be pungent. If you smell ammonia or any off-putting scent, it's best to leave it alone. If you're up for it, it could be worth asking how long your pizzeria leaves its cheese on the tables, which will help you decide whether you want that Parmesan all over your pizza or not.