title: Adaptation response of Pseudomonas fragi on refrigerated solid matrix to a moderate electric field.
abstract: BACKGROUND
  Moderate electric field (MEF) technology is a promising food preservation strategy since it relies on physical properties-rather than chemical additives-to preserve solid cellular foods during storage. However, the effectiveness of long-term MEF exposure on the psychrotrophic microorganisms responsible for the food spoilage at cool temperatures remains unclear.
  
  
  RESULTS
  The spoilage-associated psychrotroph Pseudomonas fragi MC16 was obtained from pork samples stored at 7 °C. Continuous MEF treatment attenuated growth and resulted in subsequent adaptation of M16 cultured on nutrient agar plates at 7 °C, compared to the control cultures, as determined by biomass analysis and plating procedures. Moreover, intracellular dehydrogenase activity and ATP levels also indicated an initial effect of MEF treatment followed by cellular recovery, and extracellular β-galactosidase activity assays indicated no obvious changes in cell membrane permeability. Furthermore, microscopic observations using scanning and transmission electron microscopy revealed that MEF induced sublethal cellular injury during early treatment stages, but no notable changes in morphology or cytology on subsequent days.
  
  
  CONCLUSIONS
  Our study provides direct evidence that psychrotrophic P. fragi MC16 cultured on nutrient agar plates at 7 °C are capable of adapting to MEF treatment.
authors.affiliation: Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, People's Republic of China.|College of Staple Food Technology, Chinese Academy of Agricultural Sciences, Institute of Food Science and Technology, Harbin, 151900, People's Republic of China.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Chen
authors.affiliation: Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, People's Republic of China.|College of Staple Food Technology, Chinese Academy of Agricultural Sciences, Institute of Food Science and Technology, Harbin, 151900, People's Republic of China.
authors.forename: Honghai
authors.initials: H
authors.lastname: Hu
authors.affiliation: Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, People's Republic of China.|College of Staple Food Technology, Chinese Academy of Agricultural Sciences, Institute of Food Science and Technology, Harbin, 151900, People's Republic of China.
authors.forename: Chunjiang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, People's Republic of China.|College of Staple Food Technology, Chinese Academy of Agricultural Sciences, Institute of Food Science and Technology, Harbin, 151900, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Huang
authors.affiliation: Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, People's Republic of China.
authors.forename: Dequan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing, 100193, People's Republic of China. zhang.h07@hotmail.com.|College of Staple Food Technology, Chinese Academy of Agricultural Sciences, Institute of Food Science and Technology, Harbin, 151900, People's Republic of China. zhang.h07@hotmail.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D000818:Animals; D018533:Biomass; D002463:Cell Membrane Permeability / Q000502:physiology / Q000528:radiation effects; D015169:Colony Count, Microbial; D004599:Electric Stimulation Therapy; D004560:Electricity; D004789:Enzyme Activation; D057075:Enzyme Assays; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D061353:Food Storage; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010088:Oxidoreductases / Q000378:metabolism / Q000528:radiation effects; D044206:Pseudomonas fragi / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism* / Q000528:radiation effects*; D000069466:Red Meat / Q000382:microbiology; D012034:Refrigeration; D013552:Swine; D013696:Temperature; D001616:beta-Galactosidase / Q000378:metabolism / Q000528:radiation effects
chemical_list: D000255:Adenosine Triphosphate; D010088:Oxidoreductases; D001616:beta-Galactosidase
keywords: Adaptation response; Moderate electric field; Nutrient agar plates; Pseudomonas fragi; Psychrotrophic microorganisms; Solid cellular foodstuffs