Growth inhibition of Aeromonas salmonicida and Yersinia ruckeri by disinfectants containing peracetic acid

Peracetic acid (PAA) is a therapeutic agent used for disinfection in aquaculture, but it must be investigated thoroughly in order to mitigate diseases without harming the fish. Success- ful disinfectants (like PAA) should not leave dangerous residues in the environment in order to successfully contribute to sustainable aquaculture. The aim of our study was to compare the effec- tiveness of 6 commercial PAA products with different molecular PAA:H2O2 ratios to reduce bacte- rial growth of Aeromonas salmonicida and Yersinia ruckeri and to determine effective concentra- tions and exposure times. All products reduced colony-forming units (CFUs) of A. salmonicida and Y. ruckeri. Products with higher molecular PAA:H2O2 ratios inhibited growth better than products with lower molecular PAA:H2O2 ratios at the same PAA concentration; this indicates that H2O2 is not the driving force in the reduction of A. salmonicida and Y. ruckeri growth by PAA in vitro. The practical application of the products with high molecular PAA:H2O2 ratios should be prioritized if these pathogens are diagnosed.