An average freezer can typically handle foods at room temperature or even heated as long as the freezer’s capacity is not overloaded. Put a lot of hot food in the freezer, and its temperature will rise, which will negatively affect its cooling capacity. 

Rapid cooling results in the formation of small crystals, which prevents minor damage and preserves high-quality food. Even more usefully, once the food is “blast frozen,” it can be moved to a standard freezer for long-term storage, as long as it remains cold enough for food at the proper temperature.