This is a very awkward English sentence. "It is banana"? The only time I can see that being said is if the question was "So what is the answer?" "It is banana"
this is probably not intended, but in some areas of the English-speaking world, you can say "That's bananas!" like "That's nuts!" or "That's crazy!"...
Anyways, I don't think that they are refering to this, but just so people know.
That's totally bananas!
This sentence doesn´t make any sense, if it were speaking about something crazy it wouldnt be in the "food" section.
It's not awkward. it could be the answer to the following question: "What flavor is this pudding?" for instance.