Impact of plasma activated water (PAW) at different temperatures on Alicyclobacillus acidoterrestris spores

Abstract

This study aimed to determine the impact of plasma activated water (PAW) combined with heating on the Alicyclobacillus acidoterrestris spores’ inactivation. For this, viable spore counts were determined after contact with PAW at 20–90 °C/5–150 min and inactivation kinetic parameters were determined at 90 °C by fitting Bigelow and Weibull models. Results showed that A. acidoterrestris spores were resistant to PAW at room temperature (reduction <0.8 log CFU/mL after 2h of exposure), while PAW at 80 and 90 °C for 30 min inactivated 2.8 and 3.6 log CFU/mL, respectively, showing a synergistic effect (p < 0.05). Moreover, Weibull model fitted the data better (R2 ≥ 0.95) than Bigelow (R2 ≥ 0.90), due to the tail behavior observed. Although PAW sanitation is insufficient to guarantee high levels of inactivation of A. acidoterrestris spores, its association with mild temperatures reduces 1–2 log CFU/mL, potentially improving the shelf life of fruit products.