I grew tomatoes this year and then made sauce out of them about 3 weeks ago (tomatoes, onion, garlic, basil, olive oil, salt). When I opened the jar I heard the distinct sound of C02 releasing. I looked in the jar and saw a good amount of bubbling. No visible mold in the jar. It doesn't smell bad, just fermented.
I've made a variety of pickled and fermented foods before and never had a problem eating those. Kimchi comes to mind as a similar food where the fermentation comes without adding any starters, just salt, cabbage, and spices. For some reason the fact that i didn't intend to ferment the sauce is making me second guess eating it. Is it possible to use salt/vinegar to kill off any bad bacteria lingering in the sauce? What if I were to convert the sauce into a fermented ketchup?