Striving4Zen

Organic bananas are wrapped in plastic because it helps speed up the ripening process. Although all bananas are shipped in their unripened green state, conventional bananas get a quick spray of an ethylene gas to accelerate their transition from green to yellow.

Understandably, the organic bananas are not gassed and are instead prepackaged in plastic bags. Since bananas naturally give off ethylene gas, the bags allow the fruit to soak up the gas and turn yellow on their own.

Source