title: Oxidative stress in E. coli cells upon exposure to heat treatments.
abstract: Heat treatments are widely used by the food industry to inactivate microorganisms, however their mode of action on microbial cells is not fully known. In the last years, it has been proposed that the generation of oxidative species could be an important factor contributing to cell death by heat and by other stresses; however, investigations in this field are scarce. The present work studies the generation of reactive oxygen species (ROS) upon heat treatment in E. coli, through the use of cell staining with specific fluorochromes. Results obtained demonstrate that ROS are detected in E. coli cells when they are subjected to heat exposure, and the amount of fluorescence increases with temperature and time, as does the cellular inactivation. The addition of glutathione or tiron, a potent antioxidant and a superoxide quencher, respectively, to the heating medium protected E. coli against heat inactivation and concurrently reduced the detection of ROS, especially in the case of glutathione. Finally, recovery of heated cells under conditions that relief oxidative stress produced an increase in cell survival. Data presented in this work support the view that ROS generation and subsequent control in bacterial cells could be an essential factor determining inactivation and survival upon exposure to heat, and it could be a potential target to increase the efficacy of current treatments.
authors: Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón- IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain.
authors: María
authors: M
authors: Marcén
authors: Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón- IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain.
authors: Virginia
authors: V
authors: Ruiz
authors: Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón- IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain.
authors: Mª Jesús
authors: MJ
authors: Serrano
authors: Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón- IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain.
authors: Santiago
authors: S
authors: Condón
authors: Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Instituto Agroalimentario de Aragón- IA2 - (Universidad de Zaragoza-CITA), Zaragoza, Spain. Electronic address: manas@unizar.es.
authors: Pilar
authors: P
authors: Mañas
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002470:Cell Survival; D004926:Escherichia coli / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism*; D006358:Hot Temperature; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species
keywords: Escherichia coli; Heat treatment; Reactive oxygen species; Recovery