title: Effect of continuous ohmic heating to inactivate Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in orange juice and tomato juice.
abstract: OBJECTIVE
  The purpose of this study was to investigate the efficacy of continuous ohmic heating for reducing Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in orange juice and tomato juice.
  
  
  RESULTS
  Orange juice and tomato juice were treated with electric field strengths in the range of 25-40 V cm(-1) for different treatment times. The temperature of the samples increased with increasing treatment time and electric field strength. The rate of temperature change for tomato juice was higher than for orange juice at all voltage gradients applied. Higher electric field strength or longer treatment time resulted in a greater reduction of pathogens. Escherichia coli O157:H7 was reduced by more than 5 log after 60-, 90- and 180-s treatments in orange juice with 40, 35 and 30 V cm(-1) electric field strength, respectively. In tomato juice, treatment with 25 V cm(-1) for 30 s was sufficient to achieve a 5-log reduction in E. coli O157:H7. Similar results were observed in Salm. Typhimurium and L. monocytogenes. The concentration of vitamin C in continuous ohmic heated juice was significantly higher than in conventionally heated juice (P < 0·05).
  
  
  CONCLUSIONS
  Continuous ohmic heating can be effective in killing foodborne pathogens on orange juice and tomato juice with lower degradation of quality than conventional heating.
  
  
  CONCLUSIONS
  These results suggest that continuous ohmic heating might be effectively used to pasteurize fruit and vegetable juices in a short operating time and that the effect of inactivation depends on applied electric field strengths, treatment time and electric conductivity.
authors.affiliation: Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.
authors.forename: S-Y
authors.initials: SY
authors.lastname: Lee
authors.forename: H-G
authors.initials: HG
authors.lastname: Sagong
authors.forename: S
authors.initials: S
authors.lastname: Ryu
authors.forename: D-H
authors.initials: DH
authors.lastname: Kang
mesh_terms: D001628:Beverages / Q000382:microbiology*; D032084:Citrus sinensis; D004560:Electricity; D019453:Escherichia coli O157 / Q000502:physiology*; D005506:Food Contamination / Q000517:prevention & control*; D006358:Hot Temperature; D008089:Listeria monocytogenes / Q000502:physiology*; D018551:Solanum lycopersicum; D012486:Salmonella typhimurium / Q000502:physiology*