title: Inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in orange and tomato juice using ohmic heating.
abstract: The effects of ohmic heating on reduction of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in orange and tomato juice were investigated. Orange and tomato juice inoculated with E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes were subjected to ohmic heating with selected parameters including electric field strength from 10 to 20 V/cm and treatment times from 0 to 540 s. The number of pathogens was reduced by increasing the electric field strength from 10 to 20 V/cm as well as increasing treatment time. The population of E. coli O157:H7 was reduced more than 5 log after 120, 210, and 540 s of treatment in orange juice with 20, 15, and 10 V/cm electric field strengths, respectively. In tomato juice, levels of E. coli O157:H7 were reduced more than 5 log after 90, 180, and 480 s with the same electric field strengths. Similar phenomena were observed for Salmonella Typhimurium and L. monocytogenes, but E. coli O157:H7 was the most resistant to ohmic heating treatment. These results show that ohmic heating is potentially useful for inactivation of E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes and that the effect of inactivation depends on applied electric field strength, treatment time, pathogen species, and type of juice.
authors.affiliation: Department of Food and Animal Biotechnology, School of Agricultural Biotechnology, Seoul National University, San 56-1, Sillim-dong, Kwanak-gu, Seoul 151-742, Korea.
authors.forename: Hun-Gu
authors.initials: HG
authors.lastname: Sagong
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Choi
authors.forename: Sangryeol
authors.initials: S
authors.lastname: Ryu
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kang
mesh_terms: D001628:Beverages / Q000382:microbiology*; D032084:Citrus sinensis / Q000382:microbiology; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004553:Electric Conductivity; D055664:Electrochemical Techniques; D019453:Escherichia coli O157 / Q000254:growth & development*; D005511:Food Handling / Q000379:methods; D005519:Food Preservation / Q000379:methods; D006358:Hot Temperature; D006801:Humans; D008089:Listeria monocytogenes / Q000254:growth & development*; D018551:Solanum lycopersicum / Q000382:microbiology; D012486:Salmonella typhimurium / Q000254:growth & development*