Retorting is the thermal sterilization stage of the food canning process. Batch retorts, still or agitating, run on saturated steam or hot water. By processing under pressure it is possible to reach temperatures around 121 degrees Celsius (250 degrees Fahrenheit), which greatly speeds up the destruction of microorganisms and spores compared with boiling-water processing. Correct retort scheduling, validated for each product and container, is the foundation of canned-food safety, ensuring that even heat-resistant spores of pathogens such as Clostridium botulinum are destroyed.