An automatic packaging apparatus is provided, having a conveyor, a continuous longitudinally folded web, and cutting and sealing mechanisms for forming flexible pouches from the web. Each flexible pouch has an open end and an overlap portion specifically suitable for operation with the apparatus of this invention. The open end is separated and a load is inserted into one of the flexible pouches. After the load is inserted, air is withdrawn and a gas is preferably injected into the flexible pouch by a plurality of flat-profile snorkels, or a single, wider snorkel. The flexible pouch is then heat sealed to form a gas-tight seal. Controls, preferably including a servo mechanism, are used to simultaneously operate the cutting, sealing, fluid transfer and product infeed stations of the automatic packaging apparatus. As the flexible pouch moves from the fluid transfer station to the sealing station, the gas-tight seal is maintained.