To obtain a processed food enabling preservation and distribution at normal temperature, capable of displaying in good appearance by using a soft vessel even when the food is liquid-like, facilitating preservation, distribution and handling in heat cooking and capable of preparing very delicious cooked food in fresh state immediately after heat-cooking by heat-cooking with microwave oven, etc., and provide a method for cooking the food.

This processed food is constituted so as to seal a food 2 containing a protein such as egg, milk, soybean milk or gelatin in a vessel 1 and subject the vessel A in which the food 2 is sealed to high pressure treatment of at least ≥4,000 atmospheric pressure to sterilize and modify the food 2 sealed in the vessel 1 and sell or provide the food.