title: Listeriaphages and coagulin C23 act synergistically to kill Listeria monocytogenes in milk under refrigeration conditions.
abstract: Bacteriophages and bacteriocins are promising biocontrol tools in food. In this work, two Listeria bacteriophages, FWLLm1 and FWLLm3, were assessed in combination with the bacteriocin coagulin C23 to inhibit Listeria monocytogenes. Preliminary results under laboratory conditions demonstrated that both antimicrobials act synergistically when they were applied in suboptimal concentrations. The combined approach was further assessed in milk contaminated with 5×10(4) CFU/ml L. monocytogenes 2000/47 and stored at 4 °C for 10 days. When used alone, phage FWLLm1 added at 5×10(6) PFU/ml, FWLLm3 at 5×10(5) PFU/ml and coagulin C23 at 584 AU/ml kept L. monocytogenes 2000/47 counts lower than the untreated control throughout storage. However, when used in combination, inhibition was enhanced and in the presence of FWLLm1 and coagulin C23, L. monocytogenes 2000/47 counts were under the detection limits (less than 10 CFU/ml) from day 4 until the end of the experiment. Resistant mutants towards phages and coagulin C23 could be obtained, but cross-resistance was not detected. Mutants resistant to FWLLm3 and coagulin C23 were also recovered from surviving colonies after cold storage in milk which may explain the failure of this combination to inhibit L. monocytogenes. Remarkably, the fraction of resistant mutants isolated from the combined treatment was lower than that from each antimicrobial alone, suggesting that synergy between bacteriocins and phages could be due to a lower rate of resistance development and the absence of cross-resistance.
authors.affiliation: DairySafe Group, Department of Technology and Biotechnology of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), 33300 Villaviciosa, Asturias, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Rodríguez-Rubio
authors.affiliation: DairySafe Group, Department of Technology and Biotechnology of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), 33300 Villaviciosa, Asturias, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: García
authors.affiliation: DairySafe Group, Department of Technology and Biotechnology of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), 33300 Villaviciosa, Asturias, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Rodríguez
authors.affiliation: Food, Water and Environmental Microbiology Group, Institute of Environmental Science and Research, Christchurch Science Centre, Christchurch 8041, New Zealand.
authors.forename: Craig
authors.initials: C
authors.lastname: Billington
authors.affiliation: Food, Water and Environmental Microbiology Group, Institute of Environmental Science and Research, Christchurch Science Centre, Christchurch 8041, New Zealand.
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Hudson
authors.affiliation: DairySafe Group, Department of Technology and Biotechnology of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), 33300 Villaviciosa, Asturias, Spain. Electronic address: bmf1@ipla.csic.es.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Martínez
mesh_terms: D000818:Animals; D001430:Bacteriocins / Q000494:pharmacology*; D001435:Bacteriophages / Q000502:physiology*; D003080:Cold Temperature; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000502:physiology / Q000821:virology*; D050296:Microbial Viability / Q000187:drug effects; D008892:Milk / Q000382:microbiology*; D012034:Refrigeration
chemical_list: D001430:Bacteriocins
keywords: Bacteriocin; Bacteriophage; Listeria monocytogenes; Milk; Resistance; Synergism