Underwater shock waves are pressure discontinuities generated by means of high voltage electric discharges in water. Escherichia coli
O157:H7, Salmonella Typhimurium and Listeria monocytogenes were exposed to shock waves. The influence of the pulse of light produced
by the electric discharge, acoustic cavitation produced by the shock waves, the phase of growth and shock wave dosage on bacteria
inactivation was evaluated. Inactivation of bacteria by shock waves ranged from 0 to 3.18 log10 CFU/ml. L. monocytogenes was the most
susceptible microorganism, 3.17 log10 CFU/ml inactivation was achieved with 350 shock waves. At the same shock wave dosage, 1.68 log10
CFU/ml and 0.56 log10 CFU/ml inactivation was achieved for S. Typhimurium and E. coli O157:H7, respectively. Even if the achieved
inactivation still is of little practical value, higher shock wave energy may enhance bactericidal activity. The analysis of variance revealed that
synergy between light and the other factors contributed to bacterial inactivation. Differences in the response of bacteria, along with data
analysis, suggest different mechanisms of inactivation by shock waves.
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