title: Leuconostoc bacteriophages from blue cheese manufacture: long-term survival, resistance to thermal treatments, high pressure homogenization and chemical biocides of industrial application.
abstract: Nine Leuconostoc mesenteroides phages were isolated during blue cheese manufacture yielding faulty products with reduced eye formation. Their morphologies, restriction profiles, host ranges and long-term survival rates (25°C, 8°C, -20°C and -80°C) were analysed. Based on restriction analysis, six of them were further examined regarding resistance to physical (heat and high pressure homogenization, HPH) and chemical treatments (ethanol, sodium hypochlorite, peracetic acid, biocides A, C, E and F). According to their morphology, L. mesenteroides phages studied in the present work belonged to the Caudovirales order and Siphoviridae family. Six distinct restriction patterns were obtained with EcoRV, HindIII, ClaI and XhoI enzymes, revealing interesting phage diversity in the dairy environment. No significant reductions in phage counts were observed after ten months of storage at -20°C and -80°C, while slightly and moderate decrease in phage numbers were noticed at 8°C and 25°C, respectively. The phages subjected to heat treatments generally showed high resistance at 63°C and moderate resistance at 72°C. However, 80°C for 30 min and 90°C for 2 min led to complete inactivation of viral particles. In general, the best ethanol concentration tested was 75%, as complete inactivation for most Leuconostoc phages within 30 min of incubation was achieved. Peracetic acid, and biocides A, C, E and F were highly effective when used at the same or at a moderately lower concentration as recommended by the producer. Usually, moderate or high concentrations (600-1,600 ppm) of sodium hypochlorite were necessary to completely inactivate phage particles. Leuconostoc phages were partially inactivated by HPH treatments as remaining viral particles were found even after 8 passes at 100 MPa. This is the first report of L. mesenteroides phages isolated from an Argentinean dairy cheese plant. The results of this work could be useful for establishing the most effective physical and chemical treatments for inactivating phages in industrial plants and laboratory environments.
authors.affiliation: Instituto de Lactología Industrial, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina.
authors.forename: Silvina A
authors.initials: SA
authors.lastname: Pujato
authors.affiliation: Instituto de Lactología Industrial, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina. Electronic address: dgugliel@fiq.unl.edu.ar.
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Guglielmotti
authors.affiliation: Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec G1K 7P4, Canada.
authors.forename: Hans-W
authors.initials: HW
authors.lastname: Ackermann
authors.affiliation: Dipartimento di Scienze e Tecnologie Agro-Alimentari, University of Bologna, Piazza Goidanich 60, 47023 Cesena, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Patrignani
authors.affiliation: Dipartimento di Scienze e Tecnologie Agro-Alimentari, University of Bologna, Piazza Goidanich 60, 47023 Cesena, Italy.
authors.forename: Rosalba
authors.initials: R
authors.lastname: Lanciotti
authors.affiliation: Instituto de Lactología Industrial, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Reinheimer
authors.affiliation: Instituto de Lactología Industrial, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina.
authors.forename: Andrea
authors.initials: A
authors.lastname: Quiberoni
mesh_terms: D001435:Bacteriophages / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D044822:Biodiversity; D002611:Cheese / Q000382:microbiology / Q000821:virology; D004202:Disinfectants / Q000494:pharmacology*; D005516:Food Microbiology; D058507:Host Specificity; D006358:Hot Temperature; D007934:Leuconostoc / Q000145:classification / Q000235:genetics / Q000821:virology*; D046529:Microscopy, Electron, Transmission; D010463:Peracetic Acid / Q000494:pharmacology; D011312:Pressure; D012973:Sodium Hypochlorite / Q000494:pharmacology; D038301:Virus Inactivation / Q000187:drug effects
chemical_list: D004202:Disinfectants; D012973:Sodium Hypochlorite; D010463:Peracetic Acid
keywords: Bacteriophages; Biocides; HPH; Heat; Inactivation; Leuconostoc