It covers all edible, internal parts of animals, such as kidneys and liver, also brains, cheeks, ears, stomachs, sweetbreads, tripe and tongue. Offal must be absolutely fresh before freezing. Look for moist, shiny meat, and avoid buying any that has a greenish color, slimy surface or an unpleasant smell.
Liver can be frozen either in large pieces or sliced. Calf's kidneys should be chopped up, but lamb's kidneys can be frozen either whole or halved. Sweetbreads are best frozen whole, after blanching.
** Asian Recipes