Provided is a method for producing a product packed in a container of a kakui (a kakui), which can suppress loss of original components of the kakui from the kakui and increase the amount of the umami components included in the kakui. A method of manufacturing a product packed in a goose container, comprising: Holding a processing target including a container and a goose container packed in the container at a temperature of 60 degrees Centigrade or more and 70 degrees Centigrade or less; holding the processing target at a temperature of 60 degrees Centigrade or more and 70 degrees Centigrade or less, It is preferable that the object to be treated is subjected to heat sterilization treatment. It is preferable that the time for which the object to be treated is held at a temperature of 60 degrees Centigrade or more and 70 degrees Centigrade or less is 4...
