Isolation and characterization of a novel phage vB_BceS_LY1 and its application to control newly isolated Bacillus cereus in milk and rice

Bacillus cereus is an important foodborne pathogen that causes food poisoning and other non-gastrointestinal infections, which could cause nausea, vomiting and diarrhea. Phages have antibacterial potential to control this pathogen, especially antibiotic resistant ones. In this study, a novel lytic Bacillus cereus phage, vB_BceS_LY1 (LY1), a new genus of the subfamily Gutmannvirinae under Caudoviricetes, was isolated from a sewage treatment plant in China. It had a large burst size of 230 PFU·Cell−1, was stable over a wide range of temperatures (4–50 °C) and pH (5–11), and was UV-resistant for 65 min. No antibiotic resistance, virulence, or lysogeny-associated genes were observed. Results showed that the phage LY1 had a good biological basis and application potential. For bacteria control, it could significantly inhibit the growth of Bacillus cereus not only in Tryptic Soy Broth, but also in milk and rice. When in the milk, phage LY1 could control the Bacillus cereus even below the detection limit at high MOI (>1000) in 12 h (4 °C). Particularly, the bacteriostatic effect reached 100% within 12 h in rice. In conclusion, phage LY1 with a high lysis capacity and stability, is considered as a novel safe and prospective biocontrol agent against Bacillus cereus.