Characterization of microbial inactivation in clear and turbid juices processed by short-wave ultraviolet light

摘要

The aim of this study was to analyze the inactivation of a wide spectrum of microorganisms in clear as well as turbid juices processed by ultraviolet light (UV-C: 0–1720 mJ/cm~2). A biodosimetry assay was used to determine the equivalent UVreduction dose (3.1 mJ/cm~2). UV-C effectiveness increased in melon (3.2 and 4.4 log-reductions of Saccharomyces cerevisiae and Escherichia coli) and orange-tangerine juices (4.7 log-reductions of E. coli) compared to carrot (2.7, 2.9, and 4.2 log-reductions of S. cerevisiae, Candida parapsilosis and Pseudomonas fluorescens), orange (1.7, 2.0, 2.9 and 4.0 log-reductions of S. cerevisiae, Zygosaccharomyces bailii, Listeria innocua, and E. coli), and orange-carrot juices (2.5, 2.5 and 2.9 log-reductions of S. cerevisiae, P. fluorescens, and E. coli). The Coroller model allowed a better fit compared to the Weibull and modified Gompertz models. UV-C effectiveness in clear juices was related to low absorbance at 254 nm, color, and turbidity; whereas, in the turbid juices, it was also linked to the presence of particle aggregates.