Inactivation of Alicyclobacillus acidoterrestris ATCC 49025 spores in apple juice by pulsed light. Influence of the initial contamination and the required reduction levels

GUERRERO S; M. FERRARIO

REVISTA ARGENTINA DE MICROBIOLOGíA

ASOCIACION ARGENTINA MICROBIOLOGIA

Lugar: Buenos Aires; Año: 2018 vol. 50 p. 3 - 11

0325-7541

The purpose of this study was to analyze the response of different initial contamination levels of Alicyclobacillus acidoterrestris ATCC 49025 spores in apple juice as affected by pulsed light treatment (PL, batch mode, Xenon lamp, 3 pulses/s, 0-71.6 J/cm2). Biphasic and Weibull frequency distribution models were used to characterize the relationship between inoculum size and treatment time with the reductions achieved after PL exposure. Additionally, a second order polynomial model was computed to relate some variables (treatment time and inoculum size) to the required A. acidoterrestris spore reduction level. PL treatment provoked up to 3.0-3.5 log reductions, depending on the initial inoculum size. Inactivation curves corresponding to PL treated samples were adequately characterized by both Weibull and biphasic models (R2adj 94-96 %), and revealed that lower initial inoculum sizes were associated with higher inactivation rates. According to the polynomial model, the predicted time for PL treatment increased exponentially with the inoculum size . .