How To Freeze Foods: The Quicker The Better

Freeze food as quickly as possible to prevent bacterial growth and protect quality.   Smaller quantities of food freeze faster than larger ones. Therefore, divide large portions  into smaller ones. Do not stack one item on top of one another until after they are frozen solid. Instead, place the foods to be frozen side by side. If your home freezer has a "quick-freeze" shelf, use it.
 
Among other benefits,  rapid freezing prevents the formation of large ice crystals throughout the food. During thawing, ice crystals damage cells and dissolve emulsions. Emulsions such as mayonnaise or cream will separate and curdle.  Therefore, don’t freeze them.
 

Source(s):
USDA Fact Sheets "Safe Food Handling"