P1-56 Use of Bacteriophage Cocktail for Biocontrol and Biofilm Removal of Bacillus cereus

Monday, July 23, 2012
Exhibit Hall (Rhode Island Convention Center)
Hyelim Yoo, Gachon University, Kyunggi-Do, South Korea
Jinyoung Kim, Gachon University, Kyunggi-Do, South Korea
Young-Duck Lee, Gachon University, Kyunggi-Do, South Korea
Jong-Hyun Park, Gachon University, Kyunggi-Do, South Korea
Introduction:  Bacillus cereus is a spore-forming foodborne pathogen which can cause emetic or diarrheal syndromes. Because it may form biofilms under various conditions, it can be difficult to control in foods. Bacteriophages are a potential means of controlling B. cereus.

Purpose:  The aims of this study were to isolate bacteriophages of B. cereusfrom various environments and to identify their characteristics.

Methods:  After isolating the bacteriophages by the plaque assay, they were characterized by their host spectrum, one-step growth curve, stability, and morphological characteristics using transmission electron microscopy (TEM). A bacteriophage cocktail was used to study bio-control of B. cereus in food and biofilm removal on glass wool.

Results:  Among the nineteen bacteriophages that were isolated,  four showed a broad host spectrum on various strains of B. cereus. TEM analysis showed that bacteriophages BCP3 and BCP11 belonged to the Siphoviridae family, and BCP9 and BCP18 belonged to the Myoviridae family. Their burst sizes were approximately 130 - 160 PFU. They generally showed stability to low pH, and exposure to 50% and 70% (v/v) ethanol for 30 min caused a 5- and 7-log PFU/ml decrease, respectively. They showed instability to 70°C after 40 minutes. A cocktail of the four bacteriophages caused a 5-log CFU reduction of B. cereus in radish sprouts after 3 hours. After a 4-h treatment with the bacteriophage cocktail, biofilm-forming B. cereus was not detected on the glass wool.

Significance:  Bacteriophages have the potential to control B. cereus in foods or in biofilms.