The organic acids in SoftAcid® have two functions as antimicrobial agents. Their primary action is through pH-depression. In addition, the ability of organic acids to change from undissociated to dissociated form, depending of the environmental pH, makes them effective antimicrobial agents.
When an organic acid is in the undissociated form it can freely diffuse through the semi-permeable cell wall of micro-organisms into their cell cytoplasm. Once inside the cell, where the pH is maintained near 7, the acid will dissociate and pH will decrease, thus disturbing and finally killing the micro-organism.
In addition, there is strong evidence that the lignosulfonic acid portion of SoftAcid has an inhibitory effect on bacterial biofilm formation, probably by binding to specific bacterial cell-surface bound proteins involved in the process of chemical cell-to-cell signalling (quorum sensing) which controls the bacterial population density. Furthermore, the lignosulfonic acid molecules will interact with extracellular proteins in an already formed biofilm matrix, thus disrupting the biofilm structure and making the bacterial cells more susceptible to the antimicrobial action of the organic acid.