Fill the food packaging bag with nitrogen to isolate food, fruits, etc. from contact with the air, and prevent the oxidation, fading, corruption of the food caused by direct contact between the atmosphere and various packaged foods, as well as the damage of various molds and bacteria to the food. Thereby ensuring the freshness of the packaged food and prolonging the storage period of the packaged food! This method, due to the special physical properties of nitrogen gas is different from chemical anti-corrosion treatment, so it will not leave any residue. At present, this packaging has been widely used in the packaging of various foods such as potato chips, jerky, fresh fruits, vegetables, nuts, biscuits and so on. The HTN pressure swing adsorption nitrogen generator independently developed and manufactured by Hunter is suitable for the fields of green grain storage, food nitrogen-filled packaging, vegetable preservation, wine sealing (canning) and preservation.