Ozone-high hydrostatic pressure synergy for the stabilization of refrigerated pitaya (Stenocereus pruinosus) juice

The synergistic effect of ozone (24 mg/O3/L/min) and high hydrostatic pressure (HHP, 179–321 MPa) combination was evaluated with regard to individual effects of these over the microbial population in pitaya juice by using a response surface methodology and a repeated measures design with Tukey test. Treatment with 300 MPa/5 min reduced 6.89-log10 and 0.89-log10 CFU/mL of Saccharomyces cerevisiae and Listeria innocua population, respectively; and treatment with 9.6 min of ozonation time reduced 0.47-log10 and 2.51-log10 CFU/mL of S. cerevisiae and L. innocua population respectively; however, L. innocua was reduced 5.1-log10 CFU/mL with exposure to ozone for 7 min followed by 316 MPa/5 min. Likewise, these treatment conditions kept native microbiota of the juice at non-detectable levels and achieved the highest sensory preference (79%) as compared to untreated juice at 30 d (5 ± 2 °C). Ozone-HHP reduced bacterial counts suggesting a microbiologically safe pitaya juice, contrary to what was obtained with individual application of these technologies.