The evolution of cheese dates back 5,000 years to the time when people learned to preserve naturally curdled milk by draining off the watery whey, then salting the curds to flavor and preserve them. At some point it was discovered that the texture of the curd became more pliable with the help of the enzyme rennet, which naturally occurs in animal stomachs. The growth and activity of enzymes in cheese caused it to develop and change. It was later discovered that some cheeses could be aged and kept for months or years.

Adding acid or starter culture to milk, causing the sugar in the milk to ferment, makes cheese. Curdling (coagulating) milk causes it to separate into semi-solid curds and liquid whey. The type of cheese produced is determined by a number of factors, including the type of culture, the amount of whey remaining in the curds, how the curd is worked after whey drainage, the amount of pressure applied to the curds and if the cheese is intended to be fresh or aged. In the case of aged cheese, the curds are stirred and in some cases heated, then the whey is drained and the remaining curds are salted and pressed to form cheese. Fresh cheeses, on the other hand, can be made from uncooked or cooked curd, drained of whey to varying degrees and formed or unformed. Fresh cheeses are made to be consumed immediately while aged cheeses can be ripened for a period of time ranging from weeks to years.

When purchasing cheese, make sure the package is properly and tightly wrapped and sealed and that the cheese inside looks appealing. Do not purchase any cheese that looks dry or discolored, as the package seal may be broken. With fresh cheeses, check the freshness date on the package. Most cheeses will maintain their flavor and quality in your refrigerator if properly stored. Keep cheeses in the refrigerator until needed. Once opened, follow these simple guidelines for storing cheese:

• Fresh cheeses should be treated just like milk and kept refrigerated.
• Many fresh cheeses can last for a few weeks if properly stored, so note the freshness date on the package before you buy. If you detect mold on a fresh cheese, discard it.
• Soft-ripened cheeses will keep for up to several weeks if properly stored. If you plan to use a soft-ripened cheese within a few days, store it in the refrigerator in its original plastic wrap.
• Semi-hard and hard cheeses can remain enjoyable for four to eight weeks if properly stored. If you do not plan to consume these cheeses within a few days after the original package is first opened, consider removing the original plastic wrap and rewrapping in parchment or wax paper, which allows the cheese to breathe. After rewrapping a cheese, store in a covered plastic container or an open resealable-type food storage bag.
• Very hard cheeses (typically used for grating) are much lower in moisture than other cheeses and will keep for months if stored in the same way as semi-hard cheeses.

One ounce of natural cheese, such as Cheddar, Jack, or Mozzarella, contains approximately 20 percent of a person’s recommended daily calcium intake. Those who are lactose-sensitive or lactose-intolerant can still enjoy cheese as long as they eat natural hard (aged) or soft-ripened varieties, which contain little or no lactose.

• Shred, grate, or cut cheese into pieces before melting. Then to melt, use a low temperature for a short time. Hard cheeses can withstand higher cooking temperatures than soft cheeses.
• Hard cheeses such as Dry Jack, Aged Cheddar and Parmesan are ideal for cooking and baking.
• Add cheese toppings to food at the end of baking or broiling and heat just long enough to melt.
• Soft and soft-ripened cheeses have enough water to make them blend well into soufflés, custards and fillings; remove the rind before using.
• Minimize stirring, which can cause the cheese to become lumpy.
• Blue and pungent cheeses should be added sparingly since they tend to melt quickly and burn easily. In baking, chill cheese before grating and adding to pastry dough.
• Weight is the best method to measure cheese for recipes: 4 ounces of natural cheese equals 1 cup shredded cheese (1 ounce = 1/4 cup).