The VP system involves exhaustion of oxygen from the package and sealing immediately or flushing the package with a single gas or combination of gasses. MAP is defined as packaging of a product in an atmosphere which has had a one-time modification of gaseous composition so that it is different from that of air, which normally contains 78.08% nitrogen, 20.96% oxygen, and 0.03% carbon dioxide (USDHHS USFDA, 2009). Modifications of the package atmosphere could involve changing the composition of the gasses or inclusion of other gasses such as carbon monoxide (CO).