Hiya I have also read about 6% acetic acid for 20-30mins for some of the mycobacteria but not others,I guess we just need to make sure the information is from an experiment on a reputable site. So much info out there, hard to know which is correct, to be on the safe side I will go for 10 for now. However I also am concerned about killing all the good bacteria which keep the bad in check. Confusing!