Exploring thermosonication as non-chemical disinfection technology for strawberries

Abstract

The scope of this work was to study the efcacy of the combination of sonication at 35 or 130 kHz with three temperature treatments: 20, 50 and 55 ºC, on the population of artifcially inoculated Listeria innocua in strawberries, and on their overall quality. Prior in vitro results showed that temperature was the main factor in decreasing L. innocua population: a maximum of 3.8 log reductions was obtained with sonication at 130 kHz and 55 ºC for 15 min Treatments combining—or not—sonication at 130 kHz with mild emperatures (50 and 55 ºC) for 5 or 10 min were able to decrease about 3 log units of artifcially inoculated L. innocua in strawberries and about 2 log units of total aerobic mesophilic and yeasts and molds populations naturally occurring in strawberries. Thermosonication treatments did not exert a detrimental impact on fruit quality, except for those at the higher temperatures and times, which caused a change in color to more purplish and a little softening of the strawberries, which were proposed to be assessed for further processing other than fresh commercialization. Overall, the impact of sonication in fresh strawberries needs to be further investigated to fnd the adequate conditions to enhance the efects of temperature itself.