Revised by Pamela Schmutz, HGIC Food Safety Specialist and Angela Fraser, Extension Food Safety Specialist, Clemson University. Originally prepared by Pamela Schmutz, HGIC Food Safety Specialist, and Elizabeth Hoyle, Extension Food Safety Specialist, Clemson University. (New 01/99. Revised 06/08.)
Natural cheese can be unripened or ripened. Unripened cheeses include cream cheese and cottage cheese. Cheeses that are ripened by bacteria include cheddar, Swiss and Parmesan. Cheeses that are ripened by mold include Blue, Roquefort and Brie. Natural cheeses are also categorized by their degree of hardness.
Process cheese is a blend of fresh and aged natural cheese (such as cheddar or colby) that has been melted, pasteurized and mixed with an emulsifier. Process cheese is milder in flavor and softer than the natural cheese from which it was made. It also has very good melting properties.
Refrigerate all cheese between 35 and 40 °F in its original wrapping until ready to use. It is best to store cheese in a refrigerator drawer so it does not pick up off-flavors from other foods. If cheese is removed from its original packaging, wrap it tightly with plastic film wrap or foil to prevent air pockets. Once cheese is exposed to air, molding and dehydration might occur. To protect cheese from mold it is best to double-wrap cheese and place it in a sealed container after each use. Strong-smelling cheeses, like Limburger, should be well-wrapped and kept in a separate container to prevent odors from transferring to other foods.
The "best if used by" date tells you how long the product will keep its best flavor or quality. The term is not a safety date. "Best if used by" dates are general guidelines, as some foods may deteriorate more quickly and other foods may last longer than the times suggested. A number of factors, such as improper handling and inadequate storage, can shorten the shelf-life of a food. Many foods can be eaten after the "best if used by" date if properly stored and handled.
Caution: Throw out soft cheeses that have been at room temperature for more than four hours.
As a general rule, the harder the cheese, the longer its shelf-life. But remember, many types of natural cheese will continue to ripen, no matter how carefully they are stored. Hard cheeses will generally keep for several months, whereas softer cheeses will keep from one to three weeks after opening. Large pieces of cheese tend to keep longer than shredded cheese.
Unopened packages of process cheese can be used up to six months if refrigerated at 40 °F or below. Opened packages should be tightly rewrapped, refrigerated, and used within three to four weeks.
Most hard cheeses and process cheeses can be frozen, but there will be changes in texture. For this reason, thawed cheese is best used crumbled or shredded, in salads or as toppings or in cooked dishes.
Tips for Freezing Cheeses:
Molds spread through cheese by producing "hyphae," which are root-like structures. In hard cheeses, such as cheddar and many processed cheeses, these mold hyphae do not penetrate very far below the surface. Mold that is not part of the manufacturing process of a cheese should be handled as shown below.
Hard Cheese: If the block of cheese is large and molding is not extensive, remove the mold to save the remaining cheese. Remove at least 1-inch around and below the mold spot. Keep the knife out of the mold itself so it will not contaminate other parts of the cheese. Mold requires oxygen to grow, so tightly rewrap the remaining cheese. The old advice to wipe the cheese with a vinegar solution is no longer recommended and is not required to prevent further mold growth.
Semi-Soft & Soft Cheese & All Types of Crumbled, Shredded, & Sliced Cheese: Discard soft cheese, cheese that has a loose-knit curd (such as some colbys), and shredded or sliced cheese if it contains molds that are not a part of the manufacturing process. These molds can be dangerous. Foods with high moisture content can be contaminated below the surface. Shredded, sliced, or crumbled cheese can be contaminated by the cutting instrument. Moldy soft cheese can also have bacteria growing along with the mold.
Caution: Never open extremely moldy cheese in the kitchen. Do not sniff the moldy item. Wrap all moldy trimmings and moldy cheeses in plastic wrap and place in a covered trash can.
Pregnant women and newborns, older adults, and people with weak immune systems due to cancer treatments, AIDS, diabetes or kidney disease are at risk for becoming seriously ill from eating foods that contain Listeria monocytogenes. People in these at-risk groups should not eat feta, Brie, Camembert, blue-veined cheeses, or Mexican-style soft cheeses such as queso blanco and queso fresco unless labeled pasteurized. For more information on Listeriosis see HGIC 3639, Listeriosis & Pregnancy: A Food Safety Concern.
Cheese cut into small pieces or shredded promotes more even melting in a shorter amount of time. When you add cheese to any recipe, cook on low heat, stirring constantly. High heat will toughen cheese and make it stringy. When you are making a sauce with cheese in it, add cheese as the last ingredient and heat until just melted. Process cheese melts more smoothly than natural cheese.
Remove the wrapping and place on a microwave-safe plate. Microwave at 30 percent until cheese reaches desired softness and/or temperature. Check every 10 seconds to prevent overheating. Cooking times will vary among microwave ovens. Use this method to prepare cheese nachos without making the cheese tough.
The flavor of cheese is best when eaten at room temperature, so remove from refrigerator before serving time. Soft cheeses take a shorter amount of time to come to room temperature than firm and hard cheeses. Only set out the amount of cheese you will eat to prevent the cheese from becoming dry and tough from being repeatedly warmed and chilled.
Cheese will shred more easily if well-chilled. It can also be placed in the freezer for 30 minutes before shredding.
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