Are really brown bananas OK to eat?

What you see: A very black or dark banana
What it is: Just a very, very ripe banana
Eat or toss? Eat! Super dark bananas are great for baking breads or freezing for later use (mmm..smoothies). Chiquita has a nifty visual tool on its website that will help you size up your banana's ripeness and suitability for a wide range of recipes
Super brown, basically black bananas look, well, gross. But while they may be unappetizing in the fruit bowl, Chiquita says those brown beasts actually pack more antioxidants than their younger, prettier cousins. As long as you don’t see mold or ooze, they’re safe to eat, and they’re ideal for baking. Or, pop them in a bag in the freezer. Once you’ve accumulated several, blend them with whatever other yummy things you might have on hand (Nutella? Peanut butter? Yogurt?) for a delicious (and healthy!) frozen dessert. Starting to get hungry? Check out our post on frozen banana ice cream.

SOURCES:
Waste Free Kitchen Handbook p. 149
Chiquita Ripeness-2-Recipe Tool
Utah State University Cooperative Extension - Banana