1) Water content of food
The freezing temperature varies with the water content of food. For example: Fruits which have more water content than meat, have lower freezing temperatures than meat. Therefore, higher the water content lower the freezing temperature.
When food have water soluble components, it will reduce the freezing temperature.This is called freezing point depression.
3)Type of packaging used.
If the packaging used is very thick and dense, it will add more resistance for heat transfer. Therefore a lot of energy would be needed in such situations for freezing.