Effects of ultraviolet-C light-emitting diodes at 275 nm on inactivation of Alicyclobacillusacidoterrestris vegetative cells and its spores as well as the quality attributes of orange juice

Abstract

Alicyclobacillus acidoterrestris is a thermoacidophilic, spore-forming bacillus. A. acidoterrestris and its spores can survive in pasteurized juices and cause microbial spoilage. In this work, the effects of ultraviolet-C light-emitting diodes at 275 nm on the inactivation of A. acidoterrestris vegetative cells and its spores in commercial pasteurized orange juice were studied. Meanwhile, the effects of ultraviolet-C light-emitting diodes on the quality attributes of the orange juice were also investigated. The quantities of A. acidoterrestris vegetative cells and its spores inoculated in orange juice were reduced by 6.04 and 2.49 log10 CFU/mL after ultraviolet-C light-emitting diode treatment at 220 mJ/cm2, respectively. The Weibull and Weibull plus tail models were satisfactorily fitted to estimate the reductions of A. acidoterrestris vegetative cells and its spores in orange juice, respectively. Physicochemical properties (pH, titratable acidity, total soluble solids, and clarity) of orange juice did not change significantly after exposure to ultraviolet-C light-emitting diodes. However, the total phenolic content of orange juice decreased with increasing fluence. In addition, ultraviolet-C light-emitting diode treatment at a higher fluence led to a noticeable color difference. These results indicate that ultraviolet-C light-emitting diode treatment has a potential application in the juice processing industry.

Effect of Optimized UV-LED Technology on Modeling, Inactivation Kinetics and Microbiological Safety in Tomato Juice

“…Torkamani and Niakousari [83] showed a D10 value in orange juice of 105 mJ/cm 2 . Zhai et al [41] obtained an average value of 56 (mJ/cm 2 ) on the inactivation of Alicyclobacillus acidoterrestris in orange juice, and Baysal et al [13] a value of 9.55 (mJ/cm 2 ) on the inactivity of Alicyclobacillus acidoterrestris in apple juice, among others. On the other hand, Table 3 presents the goodness of fit in terms of R 2 .…”

“…Moreover, Ngadi et al [78] studied apple juice and applied a UV fluence of 300 mJ/cm 2 for 16 min to achieve a logarithmic reduction of 4.2 CFU/mL in E. coli O157:H7 ATCC 35150. Zhai et al [41] reported that UV-C-LED irradiation reduced the population of Zygosaccharomyces rouxii in apple juice at 4.86 log CFU/mL at 800 mJ/cm 2 . These authors concluded that the treatment has potential application in the juice processing industry.…”

“…Based on the above, studies of the effect of UV-LED on fruit juices are needed. Among the studies that we highlight and that have maintained a microbiological focus on fruit and vegetable juices are Cheng et al [39], Xiang et al [40], Zhai et al [41], D'Souza et al [42] and Baykuş et al [43]. Furthermore, a good efficiency of the UV-LED treatment can be optimized by means of a reactor design (static or dynamic) and by generating mathematical models.…”

Comparative assessment of UV-C radiation and non-thermal plasma for inactivation of foodborne fungal spores suspension in vitro

“…41 Studies have documented the successful use of UV-C radiation (100-280 nm) in decontaminating bacterial vegetative spores of Alicyclobacillus acidoterrestris. 42 Nakpan et al reported that bacterial spores exhibit an order of magnitude greater sensitivity to UV radiation compared to Aspergillus fumigatus spores. 20 As depicted in Fig.…”

Applications of light emitting diodes and their mechanism for food preservation

“…Zhai et al (2020) demonstrated the reduction of A. acidoterrestris vegetative cells and spores in commercial pasteurized orange juice with the application of UV‐C LEDs at 275 nm. The growth temperature and pH for A. acidoterrestris ranges from 20°C to 70°C, and 2.0 to 7.0, respectively (Grande et al, 2005).…”