Peracetic Acid

Peracetic acid has bactericidal activity (1.6%, 3–5 min), yeasticidal activity (0.25%, 1 min) and tuberculocidal activity (0.25% in 1 min). However, some food-associated fungi and Mycobacterium spp. are not sufficiently killed under these conditions. The antimicrobial activity of peracetic acid is explained by non-specific oxidation and disruption of cell wall permeability. No specific cellular defence mechanisms against peracetic acid have been described. Peracetic acid partially inhibits or even prevents biofilm formation. Biofilm removal is poor to moderate (0%–63%). Biofilm fixation by peracetic acid ranges from 0% to 54%. High MIC values have been reported for some meat-borne L. monocytogenes isolates, their relevance is uncertain. Low-level exposure does not alter the susceptibility of C. sakazakii, L. monocytogenes, S. enterica and Y. enterocolitica. Virulence genes may be induced (S. aureus) or reduced (L. monocytogenes). S. Typhimurium survivors of low-level exposure may be viable but not culturable. Peracetic acid can convert various beta-lactam antibiotics in wastewater, thereby reducing selection pressure. No peracetic acid-resistant isolates have been described with insufficient efficacy in suspension tests or tests under practical conditions at use concentrations, or with a contamination of disinfectants. The overall probability of resistance to peracetic acid of practical relevance is very low in the absence of biofilm.