The decontamination effect of pulsed and continuous power ultrasound, provided at either controlled or uncontrolled
temperature regimes, was studiedwith reference to nativemicroflora and inoculated pathogenic bacteria
in wastewater obtained by fresh-cut lamb's lettuce washing. Results showed that decontamination efficacy
increased with increasing specific energy and was higher when ultrasound treatment was provided under
uncontrolled temperature regime. Continuous ultrasound supplied without temperature control allowed to
achieve 3.2 Log reductions of native microflora during 20 min treatment, while 5 Log reductions of inoculated
Listeria monocytogenes, Escherichia coli and Salmonella enterica were attained within 5 min of ultrasonication.
The heat generated during continuous ultrasound accounted for approximately 58% of the total decontamination
effect against L. monocytogenes, while it contributed for 100% to E. coli and S. enterica inactivation.
Industrial relevance: The application of power ultrasound combined with in situ generated heat could represent
an effective tool for water decontamination and recycling in the fresh-cut industry. In addition, besides safety
requirements, this technology would also meet cost-effectiveness criteria and existing standards