Bananas, fruit, cooked meats, crisps etc are all stored/packaged in nitrogen gas, (not the liquid stuff for obvious reasons), which extends their shelf life. All the air is expelled and nitrogen gas substituted. This prevents mould growth and slows down the metabolism of fruit and veg etc.
Once you open a packet of cooked meat, crisps or pre-packed fruit/veg you expel the nitrogen and introduce air/oxygen. This then begins the action of the deterioration product.
There was once an attempt at growing square tomatoes in moulds. It meant you could pack more into a box with less space wastage. Thankfully it didn't take off.
process