The anti-microbial activity is caused by the ability of organic acid to dissociate.
The mechanism of working the organic acid blend is following. In the Undissociated from the acidisol can easily penetrate the microbial cell wall of gram negative bacteria. Inside the bacterial cell the ph is higher than it’s pka value and large proportion of acid will dissociate and release it’s hydrogen ion. The produced proton reduce the ph inside the bacterial cell and that’s why bacterial cell consume enormous amount of energy that lead the cell death by cell wall disruption.