Dips

Here's a quick rule of thumb: Dairy-based dips such as sour cream and French onion generally require refrigeration. Tomato based-dips such as salsa don't. They can be kept at room temperature until they are opened. The reason? Acidic products such as tomatoes don't encourage bacterial growth as readily as dairy products.

 Nor can dairy-based dips be frozen. Whether cheese or cream, the dairy component will separate and curdle as a result of freezing.