Some types of cheese do need to be refrigerated while other cheeses are safe at room temperature without being refrigerated.
Cheeses such as soft cheeses need to be refrigerated for safety and to prevent spoilage of the cheese.
However hard cheeses are safe out at room temperature but keeping the cheeses refrigerated keeps bacteria from growing on the cheeses and makes the cheese last longer.
Always refrigerate soft cheeses as they must be refrigerated but hard cheeses don't require refrigeration and are safe left out at room temperature.
Soft cheeses such as cream cheese, cottage cheese, shredded cheeses, and goat cheese must be refrigerated for safety.
As a general rule, hard cheeses such as cheddar, processed cheeses (American), and both block and grated Parmesan cheeses do not require refrigeration for safety, but they will last longer if kept refrigerated.
Cheese will dry out when left in open air, especially in a warmer room, and start to look crusty and crumbly.
After eight hours on a cheese board, cheddar will likely not have a lot of bacterial growth, but it won't look appealing to eat.
Cheeses that can be left unrefrigerated are Asiago D'allevo, Parmigiano Reggiano, aged Gouda, aged Cheddar, Appenzeller and Pecorino Romano.
These hard cheeses can be unrefrigerated because they have a low moisture content and develop acidity during maturation.
If you spot mold on a hard cheese, it's generally safe to cut off the moldy part and eat the rest, since the spores likely will not have spread throughout the cheese.
Another sign that a cheese has gone bad is a smell or taste of spoiled, sour milk.