You need to store all dairy products, including milk and cheese, in the refrigerator. Each kind of dairy product stays fresh when stored in the fridge for a different period of time:
Milk: Whole milk keeps for about a week after the store expiration date. Skim milk has a shorter shelf life.
Sweet (unsalted) butter: Butter has a refrigerator shelf life of about two to three weeks. Or wrap in plastic and then foil, and freeze for 8 to 12 months.
Cottage cheese, ricotta, and cream cheese: Store in the original, covered container or foil wrapping and consume within one to two weeks.
Hard and semihard cheeses: Wrap all cheese in foil, a resealable plastic bag, or plastic wrap after opening. Depending on its variety, cheese keeps in the refrigerator for several weeks to months.
Heavy cream, light cream, or half-and-half: Use within a week of purchase or freeze for longer storage.
Ice cream or frozen yogurt: Instant dessert; for eating guiltily in bed at midnight. After you open it, you should eat ice cream and frozen yogurt within two weeks. You can freeze unopened containers for up to two months.
Plain yogurt: Follow the expiration date on the package.
Sour cream: Like with all dairy products, buy the container with the latest store expiration date. Sour cream should keep for about two weeks.