Package

A package comprising:

• a tray having an opening and a top face extended around the opening;
• and
• a sheet sealed to the top face to hermetically close the opening, with the sheet being sealed to the top face to form a seal portion that has a common portion extended along an outer shape of the tray and a steam passage portion externally releasing steam from inside the tray;
• wherein the steam passage portion has an inner edge protruded from an inner edge of the common portion toward the opening so as to have an angled shape with a pointed tip, the inner edge of the steam passage portion having a portion configuring one side relative to the tip and a portion configuring another side relative to the tip, the both portions configuring the sides being curved and extended nearing each other toward the tip;
• wherein the steam passage portion has an outer edge in a curved shape with a pointed tip;
• the curved shape of the outer edge corresponding in profile to a curved shape of the inner edge of the steam passage portion;
• and
• wherein the steam passage portion includes a merging portion corresponding to a peak of the angled shape and located between the tip of the outer edge and the tip of the inner edge, and a non-merging portion located between the merging portion and the common portion, the non-merging portion having a width narrowed from the common portion toward the merging portion.