title: Enhanced bactericidal effect of enterocin AS-48 in combination with high-intensity pulsed-electric field treatment against Salmonella enterica in apple juice.
abstract: The effect of the broad spectrum cyclic antimicrobial peptide enterocin AS-48 combination with high-intensity pulsed-electric field (HIPEF) treatment (35 kV/cm, 150 Hz, 4 micros and bipolar mode) was tested on Salmonella enterica CECT 915 in apple juice. A response surface methodology was applied to study the bactericidal effects of the combined treatment. The process variables were AS-48 concentration, temperature, and HIPEF treatment time. While treatment with enterocin AS-48 alone up to 60 microg/ml had no effect on the viability of S. enterica in apple juice, an increased bactericidal activity was observed in combination with HIPEF treatments. Survival fraction was affected by treatment time, enterocin AS48 concentration and treatment temperature. The combination of 100 micros of HIPEF treatment, 30 microg/ml of AS-48, and temperature of 20 degrees C resulted in the lowest inactivation, with only a 1.2-log reduction. The maximum inactivation of 4.5-log cycles was achieved with HIPEF treatment for 1000 micros in combination with 60 microg/ml of AS-48 and a treatment temperature of 40 degrees C. Synergism between enterocin AS-48 and HIPEF treatment depended on the sequence order application, since it was observed only when HIPEF was applied in the presence of previously-added bacteriocin. The combined treatment could improve the safety of freshly-made apple juice against S. enterica transmission.
authors.affiliation: Area de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Martínez Viedma
authors.forename: Angel
authors.initials: A
authors.lastname: Sobrino López
authors.forename: Nabil
authors.initials: N
authors.lastname: Ben Omar
authors.forename: Hikmate
authors.initials: H
authors.lastname: Abriouel
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; D004357:Drug Synergism; D004574:Electromagnetic Fields; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D027845:Malus / Q000382:microbiology; D019779:Salmonella enterica / Q000187:drug effects / Q000254:growth & development*
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; C466236:enterocin AS-48, Enterococcus faecalis