title: Biodiversity of lactococcal bacteriophages isolated from 3 Gouda-type cheese-producing plants.
abstract: This study reports on the identification and characterization of bacteriophages isolated from cheese-production facilities that use undefined, mixed starter cultures. Phage screening was carried out on whey samples isolated from 3 factories, 2 utilizing one particular undefined starter mixture and 1 utilizing another undefined starter mixture. Phage screening was carried out using 40 strains isolated from the 2 mixed starter cultures, and phages were profiled using host range, electron microscopy, multiplex PCR, and DNA restriction analysis. Twenty distinct lactococcal phages were identified based on host range and DNA restriction profiles, all belonging to the 936-type phage species. Nineteen of these phages were found to be able to infect both recognized subspecies of Lactococcus lactis. Restriction of phage DNA isolated using a newly developed guanidinium thiocyanate disruption method showed that the genomes of the 20 isolated phages were between 26 and 31 kb in size. It is evident from this study that the use of mixed starters creates an ideal environment for the proliferation of different phages with slightly varying host ranges. Furthermore, in this environment, members of the 936-type phage species clearly dominated the phage population.
authors.affiliation: Department of Microbiology, University College Cork, Cork, Ireland.
authors.forename: James
authors.initials: J
authors.lastname: Murphy
authors.forename: Bridget
authors.initials: B
authors.lastname: Royer
authors.forename: Jennifer
authors.initials: J
authors.lastname: Mahony
authors.forename: Lesley
authors.initials: L
authors.lastname: Hoyles
authors.forename: Knut
authors.initials: K
authors.lastname: Heller
authors.forename: Horst
authors.initials: H
authors.lastname: Neve
authors.forename: Martin
authors.initials: M
authors.lastname: Bonestroo
authors.forename: Arjen
authors.initials: A
authors.lastname: Nauta
authors.forename: Douwe
authors.initials: D
authors.lastname: van Sinderen
mesh_terms: D001435:Bacteriophages / Q000302:isolation & purification / Q000378:metabolism*; D044822:Biodiversity; D002611:Cheese / Q000382:microbiology / Q000821:virology*; D005524:Food Technology; D017045:Lactococcus / Q000821:virology*; D008854:Microscopy, Electron; D060885:Multiplex Polymerase Chain Reaction
keywords: 936-type phage; cheese whey; lactic acid bacteria; starter culture