Well, it is not in plural form, so the sentence should be correct. If it's "nossas frutas" I suppose it should be "our fruits", then.
It's not correct. Categorial meaning in English is expressed using the singular while in Portuguese and Spanish it is in the plural
-Fruits and vegetables
-I eat different fruits.
-They reap the fruits (or fruitage) of our labor.
Wrong or right, not sure but I've definitely heard these said countless times before.
Why does "i like fruit" require "frutas", but "our fruit" require "fruta"?
In the sentence "nossa fruta", is the speaker referring to one piece of fruit?
It depends on the context.
I've just imagined a producer being interviewed and talking about a kind of fruit they grow, for example, pitaia ♥♥♥♥♥♥
Then, he might say "Nossa fruta é produzida de acordo com as condições ideais, ..."
Is he talking about "our fruit" or "our fruits" when he says that? If he's asked if he likes fruit, would he say "eu gosto de fruta" or "eu gosto de frutas"?