Listeria innocua Multi-target Inactivation by Thermo-sonication and Vanillin

Hurdle technology combining an emerging preservation technique such as low-frequency ultrasound is an alternative for processing juices that are susceptible to suffer a loss of quality due to traditional heat treatments. Predictive microbiology allows evaluation of the effectiveness of preservation techniques and its combinations in order to enhance both food quality and safety. Listeria innocua inactivation by thermo-sonication along with vanillin was investigated. Fermi model (R (2) (adj)= 0.970 +/- 0.02) and surface response methodology (p < 0.05) were utilized in order to evaluate the survival of L. innocua to a multi-target treatment and to predict the interactions of studied techniques, high-intensity/low-frequency ultrasound (20 kHz/400 W) at selected wave amplitudes (60, 75, or 90 mu m), temperature (40, 50, or 60 A degrees C), and vanillin (200, 350, or 500 mg/kg). A combination of ultrasound, vanillin, and temperature enhanced L. innocua inactivation as described by Fermi parameters a and t (c), which decreased as the studied effects increased. A multi-target inactivation effect was observed for a temperature range of 45-55 A degrees C.