Mild heat and ultraviolet radiation in sequence to inactivate Alicyclobacillus acidoterrestris spores in apple juice

Mild heat followed by UV treatment was investigated in this study on apple juice inoculated with the spores of Alicyclobacillus acidoterrestris. Commercially pasteurized apple juice was inoculated with the spores of Alicyclobacillus acidoterrestris and subjected to mild heat treatment to ensure at least 90 % spore germination. The juice was then subjected to UV-C light of intensity between (1.4-1.6) mW/cm 2 for various times between 10 s to 600 s. A 4.2 log reduction was obtained upon combined heat treatment at 52 °C for 38 min followed by UV-C treatment of (1.4-1.6) mW/cm2 for 60 s. This treatment was compared with commercial pasteurization by head space GC-MS analysis for volatile fraction in apple juice and sensory evaluation of taste, color, and smell. Our results indicated that the quality attributes did not change due to combined heat and UV-C treatment of the commercially pasteurized juice.