TY - JOUR
T1 - Synergistic effect of 222-nm krypton-chlorine excilamp and mild heating combined treatment on inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice
AU - Kang, Jun Won
AU - Kim, Woo Ju
AU - Kang, Dong Hyun
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/9/16
Y1 - 2020/9/16
N2 - Simultaneous treatment with 222-nm KrCl excilamp and mild heating (EX-MH) at 45, 50 and 55 °C showed synergistic bactericidal effects on non-acid and acid adapted cells of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice. In particular, acid-adapted pathogens exhibited increased resistance to EX-MH compared to pathogenic bacteria that were not acid-adapted. Also, elucidation of the synergistic bactericidal mechanism of EX-MH was performed through several assays and this mechanism was described as follows: (i) when KrCl excilamp (EX) and mild heating (MH) are applied simultaneously, MH reversibly inactivates the antioxidant enzyme, superoxide dismutase (SOD), thereby increasing accumulation of reactive oxygen species (ROS) generated by EX and thus inducing synergistic ROS generation, (ii) ROS production induces lipid peroxidation occurrence in the cell membrane, (iii) this lipid peroxidation occurrence in the cell membrane induces synergistic destruction of cell membrane, resulting in synergistic cell death. While EX-MH of 45, 50, or 55 °C reduced E. coli O157:H7 (the pathogen most resistant to EX-MH) in apple juice by 5-log, the qualities such as color (L*, a*, and b*), total phenolic compounds (TPC), and DPPH free radical scavenging activity of apple juice did not change significantly (P > 0.05). This study not only suggests the applicability of EX-MH to the apple juice industry, but also can be used as baseline data for future relevant research.
AB - Simultaneous treatment with 222-nm KrCl excilamp and mild heating (EX-MH) at 45, 50 and 55 °C showed synergistic bactericidal effects on non-acid and acid adapted cells of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice. In particular, acid-adapted pathogens exhibited increased resistance to EX-MH compared to pathogenic bacteria that were not acid-adapted. Also, elucidation of the synergistic bactericidal mechanism of EX-MH was performed through several assays and this mechanism was described as follows: (i) when KrCl excilamp (EX) and mild heating (MH) are applied simultaneously, MH reversibly inactivates the antioxidant enzyme, superoxide dismutase (SOD), thereby increasing accumulation of reactive oxygen species (ROS) generated by EX and thus inducing synergistic ROS generation, (ii) ROS production induces lipid peroxidation occurrence in the cell membrane, (iii) this lipid peroxidation occurrence in the cell membrane induces synergistic destruction of cell membrane, resulting in synergistic cell death. While EX-MH of 45, 50, or 55 °C reduced E. coli O157:H7 (the pathogen most resistant to EX-MH) in apple juice by 5-log, the qualities such as color (L*, a*, and b*), total phenolic compounds (TPC), and DPPH free radical scavenging activity of apple juice did not change significantly (P > 0.05). This study not only suggests the applicability of EX-MH to the apple juice industry, but also can be used as baseline data for future relevant research.
KW - 222-nm KrCl excilamp
KW - Acid adaptation
KW - Apple juice
KW - Escherichia coli O157:H7
KW - Mild heating
KW - Salmonella Typhimurium
KW - Synergistic bactericidal effect
UR - http://www.scopus.com/inward/record.url?scp=85085598571&partnerID=8YFLogxK
U2 - 10.1016/j.ijfoodmicro.2020.108665
DO - 10.1016/j.ijfoodmicro.2020.108665
M3 - Article
C2 - 32497789
AN - SCOPUS:85085598571
SN - 0168-1605
VL - 329
JO - International Journal of Food Microbiology
JF - International Journal of Food Microbiology
M1 - 108665
ER -