@ljfoo :

Dr. Falkinham said that vinegar is an acid (acetic acid) and because NTM tolerates acids, vinegar does not kill NTM.

He added, however, that vinegar - being an acid - can help dissolve mineral deposits that occur with hard water, thus possibly helping to expose to disinfectants the NTM that might have been in the mineral deposits. This might be an indirect way through which vinegar could assist in disinfection, but it does not mean that the vinegar directly kills the NTM.