How to avoid a cheese disaster
My husband came home from work one day with a pizza box. The pizza was topped with a mozzarella that was dark brown and had some black spots in it. It scared me, but he assured me it was fine. A few hours later, when I tried to make myself some warm pasta salad for dinner, the smell of the cheese made my stomach turn and I ended up throwing away my entire meal. It was only later I realized my husband had lied to me.
Most of us have experienced the exact same scenario. You buy a block of cheese at the grocery store, take it home and slice off a nice piece for your sandwich or salad, and notice that some of the cheese has turned brown or black. Your first thought is: “I wonder if it’s safe to eat that brown cheese? Should I throw it away?” Unfortunately, that question is a little harder to answer than you may think. The good news is that most often the cheese is perfectly fine – but only if you know what to look for when it comes to browning cheese.
What causes browning?
As the cheese ages, it may begin to develop a slight brown color. This happens because certain microorganisms and enzymes in the cheese react with certain bacteria, which produce substances called lipases. These lipases can, over time, break down proteins in the cheese. These proteins are responsible for keeping the moisture inside of the cheese. When that moisture is gone, water from your refrigerator evaporates or you add it yourself with a little bit of lemon juice or vinegar, different proteins work to bind those molecules together and turn that surface area into a dryer one. That’s what causes the color change – nothing else causes it.
What is safe to eat and what should you throw away?
If you see a bit of browning, chances are it’s not harmful. Keep in mind that the cheese will continue to age as it sits on your countertop. It can get even darker – but there’s no need to throw out the cheese during that time. When brown or black spots appear on your cheese, don’t be alarmed – just cut around them and continue using the rest of your mozzarella. Just like a dark beer, this cheese is still good for you!
Most often browning occurs when whole milk mozzarella is sold at room temperature. It may happen when the blocks of cheese are exposed to light, or even left out on the counter. The good news is that you probably didn’t buy a whole block of cheese and there is no need to toss it (making it a lot easier to save money when you buy in bulk). Instead, look for any block that has been wrapped in plastic film (rather than foil) and stored at a cooler temperature. Look also for a brown or black spot on the top of the cheese, rather than on the bottom. When you see these two factors in a block of cheese, it’s safe to consume that entire block.
What happens when it’s not safe to eat?
If you open a package of cheese and notice that some pieces are discolored, cut those pieces away and throw them out! (Don’t worry – you’ll have plenty to eat before the rest is gone.) It may be tempting to use your hand as a guide when cutting your cheese into smaller slices or chunks; however, you can find yourself eating unexpected substances with the larger cuts. The cheeses from which you’ve cut off large pieces should be discarded entirely.