One day it occurred to me what to try to extend the storage time of my bananas at home. The picture is after a week in the refrigerator using the simple storage method.
Step 1: Place Bananas in Bag
Place the bananas in a food-grade bag like a polyethylene type. I reuse my plastic grocery, fruit, and vegetable bags!
Step 2: Remove Excess Air
Get out as much air as you can by pressing and conforming the bag to the bananas.
Step 3: Seal Bag Closed
Lightly twist the free end of bag. Close it securely with a twist-tie or a clothes pin.
Helpers have suggested using a Ziplock (tm) storage bag as an alternative. In that case, press out the air and conform the bag to the banana(s) with the bag almost completely closed. Then, finish the closing process.
Step 4: Refrigerate Bananas
Place the bag enclosing the bananas in the refrigerator. Keep them away from the cold air vent. Avoid freezing.
Step 5: Refrigeration Duration
I have saved a banana up to five weeks. It was still OK in appearance and taste. The rest of that batch lasted for four weeks and was good.
If the bananas are pretty green when first subjected to the process, they can last the longest.
The picture was taken by a helper who refrigerated the banana for a week.