Steve told me how to do this years ago. He discovered it by accident, trying to keep bananas from rotting so quickly. It works every time. I don’t know the science behind it, but the proof is in the result.
This is what you do: When you bring a bunch of bananas home from market, rather than let them set out to ripen too quickly, wrap the bananas in a plastic bag – the type the grocer packs your groceries in. Fairly snuggly. Place the bunch in the bag, then twist the bag, removing all air as you do, then wrap the bag around the bananas.
Now put the wrapped bunch of bananas in another bag the same way, and then a third bag the same way also. Place in the back of the refrigerator or crisper.
The bananas will last quite a while in case you forget to eat them as planned.