A process of food preservation for long-term storage in which food is sealed in a container and then subjected to an elevated temperature and for a sufficient period of time so as to kill all spoilage and pathogenic microorganisms that may be harmful to human health. Various temperature-time combination exposures have been developed for destroying microorganisms. A 12-D process refers to the necessary time and temperature required to destroy the pathogenic microorganism Clostridium botulinum by a million million (10¹²) times. It uses a steam retort operated at a temperature of at least 121ºC for at least three minutes. See botulinum cook.