A web of packaging material includes a pair of flaps folded onto a backing sheet and laterally heat sealed at uniform positions along the web, forming pairs of bags having laterally opposed openings. The web is perforated at the heat seals to allow ease of separation of the pairs of bags from the web, while longitudinal perforations allow for the separation of the bags of each pair from each other. Releasable adhesive strips are provided on closure flaps to allow closure of the openings of the separated bags. The bags are filled by draping them over a carrier bar, passing them under a blower and filler, and subsequently separating the bag pairs from each other and sealing them.