title: Effect of enterocin AS-48 in combination with high-intensity pulsed-electric field treatment against the spoilage bacterium Lactobacillus diolivorans in apple juice.
abstract: Enterocin AS-48 was tested in apple juice against the cider-spoilage, exopolysaccharide-producing strain Lactobacillus diolivorans 29 in combination with high-intensity pulsed-electric field (HIPEF) treatment (35 kV/cm, 150 Hz, 4 micros and bipolar mode). A response surface methodology was applied to study the bactericidal effects of the combined treatment, with AS-48 concentration and HIPEF treatment time as process variables. At subinhibitory bacteriocin concentrations, microbial inactivation by the combined treatment increased as the bacteriocin concentration and the HIPEF treatment time increased (from 0.5 to 2.0 microg/ml and from 100 to 1000 micros, respectively). Highest inactivation (4.87 logs) was achieved by 1000 micros HIPEF treatment in combination with 2.0 microg/ml AS-48. While application of treatments separately did not protect juice from survivors during storage, survivors to the combined treatment were inactivated within the following 24 h of storage, and the treated samples remained free from detectable lactobacilli for at least 15 days at temperatures of 4 degrees C as well as 22 degrees C. The combined treatment could be useful for inactivation of exopolysaccharide-producing L. diolivorans in apple juice.
authors.affiliation: Area de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Edif. B3, Universidad de Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Martínez Viedma
authors.forename: Hikmate
authors.initials: H
authors.lastname: Abriouel
authors.forename: Angel
authors.initials: A
authors.lastname: Sobrino López
authors.forename: Nabil
authors.initials: N
authors.lastname: Ben Omar
authors.forename: Rosario
authors.initials: R
authors.lastname: Lucas López
authors.forename: Eva
authors.initials: E
authors.lastname: Valdivia
authors.forename: Olga
authors.initials: O
authors.lastname: Martín Belloso
authors.forename: Antonio
authors.initials: A
authors.lastname: Gálvez
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001430:Bacteriocins / Q000494:pharmacology*; D001628:Beverages / Q000382:microbiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D004574:Electromagnetic Fields; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D007778:Lactobacillus / Q000254:growth & development* / Q000378:metabolism; D027845:Malus / Q000382:microbiology; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D011135:Polysaccharides, Bacterial; C466236:enterocin AS-48, Enterococcus faecalis