title: Combined physico-chemical treatments based on enterocin AS-48 for inactivation of Gram-negative bacteria in soybean sprouts.
abstract: Enterocin AS-48 was tested for decontamination of soybean sprouts against Gram-negative bacteria. Although treatment with bacteriocin alone had no effect on Salmonella enterica, a synergistic antimicrobial effect was detected at pH 9.0 and in combination with moderate heat treatment. Greatest inactivation was achieved for sprouts heated for 5 min at 65 degrees C in an alkaline (pH 9.0) enterocin AS-48 solution of 25 microg/ml. Bactericidal activity against S. enterica increased greatly when enterocin AS-48 was used in washing solutions in combination with several chemical compounds: EDTA, lactic acid, peracetic acid, polyphosphoric acid, sodium hypochlorite, hexadecylpyridinium chloride, propyl-p-hydroxybenzoate, and hydrocinnamic acid. The combined treatment of enterocin AS-48 and polyphosphoric acid was tested against several other Gram-negative bacteria inoculated on sprouts. The bacteria tested showed great differences in sensitivity to polyphosphoric acid, but synergism with enterocin AS-48 was confirmed in all cases. Combinations of enterocin AS-48 (25 microg/ml) and polyphosphoric acid in a concentration range of 0.1 to 2.0% significantly reduced or inhibited growth of the populations of S. enterica, Escherichia coli O157:H7, Shigella spp., Enterobacter aerogenes, Yersinia enterocolitica, Aeromonas hydrophila and Pseudomonas fluorescens in sprout samples stored at 6 degrees C and 15 degrees C. The combined treatment could therefore be applied to reduce the risks of Gram-negative pathogenic as well as spoilage bacteria on sprouts.
authors.affiliation: Area de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas s/n, 23071 Jaén, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cobo Molinos
authors.forename: Hikmate
authors.initials: H
authors.lastname: Abriouel
authors.forename: Rosario Lucas
authors.initials: RL
authors.lastname: López
authors.forename: Eva
authors.initials: E
authors.lastname: Valdivia
authors.forename: Nabil Ben
authors.initials: NB
authors.lastname: Omar
authors.forename: Antonio
authors.initials: A
authors.lastname: Gálvez
mesh_terms: D001430:Bacteriocins / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005506:Food Contamination / Q000517:prevention & control*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D010756:Phosphoric Acids / Q000494:pharmacology; D011108:Polymers / Q000494:pharmacology; D019779:Salmonella enterica / Q000187:drug effects; D013025:Glycine max / Q000382:microbiology*
chemical_list: D001430:Bacteriocins; D010756:Phosphoric Acids; D011108:Polymers; C466236:enterocin AS-48, Enterococcus faecalis; C047269:polyphosphoric acid