title: Bacteriophages BCP1-1 and BCP8-2 require divalent cations for efficient control of Bacillus cereus in fermented foods.
abstract: Bacillus cereus is a foodborne bacterial pathogen that causes diarrhea and vomiting. In this study, the usefulness of bacteriophages to eradicate B. cereus from fermented foods was investigated. A total of 13 phages were isolated from Korean fermented food products, and 2 (BCP1-1 and BCP8-2) were further characterized. Transmission electron microscopy (TEM), restriction enzyme digestion pattern analysis, and SDS-PAGE of the structural proteins suggest that both phages belong to the family Myoviridae, containing approximately 150 kbp-long genomes. The host ranges of both phages were limited to B. cereus group species (12/13), as they were not able to lyse other Gram-positive or negative strains including Bacillus subtilis. Purified phages were used to inhibit B. cereus growth in a model fermented food system, cheonggukjang, a fast-fermented soybean paste product. BCP1-1 and BCP8-2 were able to effectively eradicate B. cereus from the food only if divalent cations (Ca²⁺, Mg²⁺, or Mn²⁺) were added to the medium. Further studies reveal that divalent cations are essential for phage adsorption, while a monovalent cation (Na⁺) is required for the post-adsorption phase of phage infection. Taken together, our findings imply that a phage could be an ideal anti-bacterial agent for use in fermented food products that require the presence of beneficial microflora and, during phage application, optimization of phage reaction conditions is critical for the successful utilization of phage biocontrol.
authors.affiliation: Department of Food Science and Technology, College of Agriculture and Life Sciences, Chonbuk National University, 664-14 Duckjin-dong, Jeonju 561-756, South Korea.
authors.forename: Nadeeka
authors.initials: N
authors.lastname: Bandara
authors.forename: Junhee
authors.initials: J
authors.lastname: Jo
authors.forename: Sangryeol
authors.initials: S
authors.lastname: Ryu
authors.forename: Kwang-Pyo
authors.initials: KP
authors.lastname: Kim
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism; D001409:Bacillus cereus / Q000254:growth & development* / Q000302:isolation & purification / Q000821:virology*; D001412:Bacillus subtilis / Q000254:growth & development; D001435:Bacteriophages / Q000254:growth & development* / Q000302:isolation & purification / Q000648:ultrastructure; D061046:Biological Control Agents; D002413:Cations, Divalent / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D005285:Fermentation; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D058507:Host Specificity; D046529:Microscopy, Electron, Transmission; D017900:Myoviridae / Q000254:growth & development / Q000302:isolation & purification / Q000648:ultrastructure; D013025:Glycine max / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D061046:Biological Control Agents; D002413:Cations, Divalent