In order to prevent the loss of natural freshness and quality, an effective and intelligent food preservation concept called Modified Atmosphere Packaging (MAP) has been developed. The use of natural gases and proper packaging materials and machines help to maintain the quality of the foodstuffs and prolong their shelf life. The MAP gas mixtures usually consist of the gases already present in the air that we breathe: carbon dioxide (CO2), nitrogen (N2) and oxygen (O2). The gases are added before the trays are sealed, making them ready for transport. Tray sealing machines with MAP are available from semi-automatic to fully-automatic in-line tray sealers.