Abstract: A carton is formed by rolling a sectorial piece of sheet material, preferably a lamination of at least paper and a plastic that is impervious to fluid, into the shape of a flattened cone. The lapping side edges and apex end of the cone are both sealed, whereas its base end is to be closed and sealed after placing a desired food product into the carton therethrough. The overlapping edge of the sealed side seam has a tab protruding therefrom, which tab is to be pulled for opening the carton by tearing same along a loop of tear-off strip around the cone. The cone is flattened along a pair of opposite indented lines preformed in the sheet material so as to extend between the apex end and base end of the cone. Each indented line is bifurcated at a midportion thereof into a pair of spaced apart branch lines to impart thickness to the carton.