title: Inactivation of Listeria monocytogenes in raw fruits by enterocin AS-48.
abstract: The purpose of this study was to determine the effect of enterocin AS-48 on Listeria monocytogenes CECT 4032 in fruits and fruit juice. Fruits were contaminated with a L. monocytogenes cell suspension, washed with enterocin AS-48 (25 microg/ml) or with sterile distilled water as control, and stored at different temperatures (-20, 6, 15, 22 degrees C). Washing treatments significantly inhibited or completely inactivated L. monocytogenes in strawberries, raspberries, and blackberries stored at 15 and 22 degrees C for up to 2 days and in blackberries and strawberries at 6 degrees C for up to 7 days. Washing treatments with enterocin AS-48 also reduced viable counts in sliced melon, watermelon, pear, and kiwi but did not avoid proliferation of survivors during storage at 15 and 22 degrees C. Added enterocin (25 microg/ml) completely inactivated L. monocytogenes in watermelon juice within 24 h. To enhance the antilisterial activity of treatments, enterocin AS-48 was tested in combination with other antimicrobial substances on sliced melon stored at 22 degrees C. The combinations of enterocin AS-48 and trisodium trimetaphosphate, sodium lactate, lactic acid, polyphosphoric acid, carvacrol, hydrocinnamic acid, p-hydroxybenzoic acid, n-propyl p-hydroxybenzoate, or 2-nitropropanol showed increased antilisterial activities compared with each antimicrobial tested separately. Washing treatments with enterocin AS-48 in combination with 12 mM carvacrol, as well as with 100 mM n-propyl p-hydroxybenzoate, avoided regrowth of Listeria during storage at 22 degrees C. Results from this study indicate that enterocin AS-48 alone or in combination with other preservatives could serve as an additional hurdle against L. monocytogenes in fruits and fruit juices.
authors.affiliation: Area de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain.
authors.forename: Antonio Cobo
authors.initials: AC
authors.lastname: Molinos
authors.forename: Hikmate
authors.initials: H
authors.lastname: Abriouel
authors.forename: Nabil
authors.initials: N
authors.lastname: Ben Omar
authors.forename: Rosario
authors.initials: R
authors.lastname: Lucas
authors.forename: Eva
authors.initials: E
authors.lastname: Valdivia
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; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005519:Food Preservation; D005638:Fruit / Q000382:microbiology*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D013696:Temperature; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; C466236:enterocin AS-48, Enterococcus faecalis