Well, a refrigerator will get you down to about 3 - 4 degrees C. A domestic freezer maybe goes down to -18 C.
If you place the camera in a sealed bag and then into the freezer, DO NOT, unseal the bag and test the camera unless you are prepared for all sorts of condensation issues in the camera / lens. Test the frozen camera while it is in the sealed bag. Let the camera come to room temp before you remove it from the sealed bag and you will be a happy chappy.