A container (120) includes a closure device (121). The closure device includes interlocking fastening strips (130, 131) and a slider (132) slidably disposed on the fastening strips for facilitating the occlusion and deocclusion of the fastening strips. The slider includes a separator (133) that facilitates the deocclusion of the fastening strips. The container includes a seal (129) to provide a leak-proof closure by facilitating the occlusion of the closure device (121) after the slider (132) has been moved in the occlusion direction (114) and reached the end of the fastening strips. The seal (129) includes a curved portion that further facilitates the leak-proof closure. Additionally, a tactile indication that the closure device (121) has been fully occluded is given as the separator (133) passes over the seal (129). Similarly, an audible indication may also be provided. The seal may be accomplished by heat sealing, ultrasonic sealing or adhesives that attach the sidewalls together.