US Patent 8127961 Double ribbed secure container

A container comprising a base (12) and lid (14) each formed of sheet plastic, wherein after food is loaded into a base cavity (20) and the lid is closed, the lid resists opening. To open the lid, a move-away tab (64) lying along the base rim portion (30) is moved by tearing along at least one line (70) so a lid rim part (50) is exposed and can be grasped to lift the lid. The base has an outer raised rib (32) that blocks access to the lid rim part until the tab, which lies between two gaps (62, 63) in the outer rib, is moved out of the way. The base also has an inner raised rib (34) that projects into a groove (46) in the lid to form a seal.