Carbon Dioxide Solutions - Freezing food
Carbon dioxide, in liquid or gaseous form, is used by the food industry for chilling, quick freezing, and refrigeration during food transport.
Cryogenic freezers produce lower temperatures than domestic models. Liquid carbon dioxide is sprayed onto the food in a cryogenic freezer. When this happens, about half of the liquid carbon dioxide becomes a solid and about half of it becomes a gas. Heat is drawn out of the food to change the solid carbon dioxide into gaseous carbon dioxide, a change of state called sublimation. This causes most of the freezing effect, but the presence of the cold gaseous carbon dioxide also helps.