Signs Your Blue Cheese Has Gone Bad

Blue cheese is known for its signature streaks of mold and funky aroma, so it can be tough to tell when the cheese is actually past its prime. However, as Healthline points out, eating spoiled blue cheese can lead to a case of food poisoning or the accidental consumption of toxic types of mold — meaning it's important to be able to spot the difference between a good blue cheese and one that's gone bad. 

Speaking to The Takeout, Wisconsin master cheesemaker Carie Wagner says, ideally, your blue cheese should feature "blue/green mold and a cream-to-white body." If you spot growths that look different from the blue cheese's intended mold, it's likely a sign the cheese has gone bad, per Culture Cheese Magazine.

These visible signs may include such colors as green, pink, or gray, and a texture that can be described as "fuzzy." If you smell the cheese and detect an odor that reminds you of ammonia, this is also a sign of spoilage. In both cases, you should toss the cheese.

Notably, blue cheese doesn't have as long of a shelf life as some other varieties. According to Cook's Illustrated, this is due to the active molds in blue cheese, along with its high moisture levels. As a result, it's best to buy blue cheese in smaller quantities at a time.

According to The Washington Post, if stored properly, blue cheese can last for a few weeks in the fridge. If you buy blue cheese that is wrapped in plastic, it's recommended that you re-wrap it once you get home, first in a layer of parchment paper and then with either aluminum foil or, if available, beeswax wrap. This two-layer wrapping method allows the cheese to breathe. Plastic wrap, on the other hand, deprives cheese of air, trapping moisture and resulting in a faster spoilage.

Cook's Illustrated offers similar advice, adding that blue cheese's signature mold needs oxygen. Without it, blue cheese will start to turn yellow green on its way to going bad. Another breathable storage option recommended by the outlet is to keep the cheese refrigerated in a loose, zip-top plastic bag. In any case, you'll want to keep blue cheese cold as this will prolong the ripening process and stave off the cheese from going bad for longer.