title: Effects of high hydrostatic pressure and temperature increase on Escherichia coli spp. and pectin methyl esterase inactivation in orange juice.
abstract: The aim of this study was to evaluate the effect of high hydrostatic pressure treatment combined with moderate processing temperatures (25 ℃-50 ℃) on the inactivation of Escherichia coli O157: H7 (ATCC 700728), E. coli K12 (ATCC 23716), and pectin methyl esterase in orange juice, using pressures of 250 to 500 MPa with times ranging between 1 and 30 min. Loss of viability of E. coli O157:H7 increased significantly as pressure and treatment time increased, achieving a 6.5 log cycle reduction at 400 MPa for 3 min at 25 ℃ of treatment. With regard to the inactivation of pectin methyl esterase, the greatest reduction obtained was 90.05 ± 0.01% at 50 ℃ and 500 MPa of pressure for 15 min; therefore, the pectin methyl esterase enzyme was highly resistant to the treatments by high hydrostatic pressure. The results obtained in this study showed a synergistic effect between the high pressure and moderate temperatures in inactivating E. coli cells.
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos, Avenida Agustín Escardino, Valencia, Spain fabiantb@iata.csic.es.
authors.forename: E F
authors.initials: EF
authors.lastname: Torres
authors.affiliation: Alpina Research Institute (IAI), Alpina Productos Alimenticios S.A, Cundinamarca, Colombia.
authors.forename: G
authors.initials: G
authors.lastname: González-M
authors.affiliation: Alpina Research Institute (IAI), Alpina Productos Alimenticios S.A, Cundinamarca, Colombia.
authors.forename: B
authors.initials: B
authors.lastname: Klotz
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos, Avenida Agustín Escardino, Valencia, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Rodrigo
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D032084:Citrus sinensis; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000254:growth & development* / Q000302:isolation & purification; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D000067030:Fruit and Vegetable Juices / Q000382:microbiology*; D006874:Hydrostatic Pressure; D050296:Microbial Viability; D013696:Temperature
chemical_list: D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase
keywords: Escherichia coli; High pressure processing; inactivation kinetics; modeling; orange juice; pectin methyl esterase