Inactivation of Listeria innocua on blueberries by novel ultrasound washing processes and their impact on quality during storage

Abstract

Abstract We explored the efficacy of ultrasound in combination with carvacrol and carbonated water as a treatment to decontaminate fresh produce using blueberries as a model system. We also evaluated its impact on the quality of blueberries during refrigerated storage. Blueberries inoculated with Listeria innocua, a model pathogen, were washed in presence of individual treatments by either 20\u202fkHz ultrasound at (20\u202fkHz), 1\u202fMHz ultrasound at (1\u202fMHz), 2\u202fmM carvacrol (CR), or carbonated water (CW) as well as their combinations at 20\u202f°C for 10\u202fmin. Individual treatments resulted in around 2 log CFU/g L. innocua reductions on the blueberries surface with 3–4 log CFU/mL viable bacteria remaining in the wash water. Comparatively, both 20\xa0kHz\xa0+\xa0CR and 1\xa0MHz\xa0+\xa0CR\xa0+\xa0CW led to significantly lower (P