An improved lidded container includes a receptacle portion with a brim having a plurality of lateral substantially straight brim wall segments provided with medial sealing beads extending between corners of the brim. The medial sealing beads are characterized in that they project away from the respective walls upon which they are disposed a maximum distance at a central portion of the wall and the medial sealing beads extend over a major portion of the length of the lateral sealing wall upon which they are disposed. Most preferably, the beads are tangent with and terminate at rounded corners between the wall segments.