I had a batch of wort get bacteria-infected before boil, as a result of a stupid thing I did (I'd mashed and lautered, then left out the wort overnight before boiling, because stupidity). It had a slight citrus/acid twang, and I thought, uh oh ... but maybe it will go away. Went ahead and boiled it, and the acid taste got stronger. Not like hop-acid, though. Citric acid. In a bad way. Stuck around throughout fermentation. Ended up dumping, because the taste was not enjoyable, and I am all about enjoyment.
Moral of the story: if you detect the acid twang after letting wort sit for a while below bacteria-killing temps (135 F), it's not gonna go away. Decide now whether to dump it or go for it, but what you taste is what you get (plus 5x more).