acetobacter oxidize ethanol to make acetic acid. It'll smell and taste like vinegar.
Since it is an aerobic process, the more oxygen you have, and the warmer the temperatures, the faster it will convert.
I used to make kombucha, and it would only take me ~7 days for conversion.
You can't kill it, without killing the yeasts too.
You need to examine your sanitation process, and eliminate potential contamination sources.
StarSan works great, but once you have acetobacter, you'd have to pasteurize to kill it off; this does not remove any existing acetic acid. Once you have it, it's there to stay.
You can still drink the beer if you can get it down, it won't hurt you; There are a lot of health benefits. It just may not be very tasty.