Psychrotrophic Brocothrix thermosphacta bacteriophages isolated from beef

Area of Science:

• Food microbiology
• Bacteriology
• Virology

Background:

• Brocothrix thermosphacta is a common spoilage bacterium in refrigerated meat products.
• Characterizing and differentiating B. thermosphacta strains is crucial for food safety and quality control.
• Bacteriophages (phages) are viruses that infect bacteria and can be highly specific.

Purpose of the Study:

• To isolate and characterize psychrotrophic bacteriophages capable of infecting B. thermosphacta.
• To evaluate the potential of phage typing for differentiating B. thermosphacta strains.
• To investigate the optimal conditions for phage activity.

Main Methods:

• Isolation of bacteriophages from spoiled beef under psychrotrophic conditions (7°C).
• Purification and characterization of isolated phages, including plaque assays and electron microscopy.
• Phage susceptibility testing of B. thermosphacta strains to determine lysotypes.

Main Results:

• Successfully isolated 21 virulent, psychrotrophic phages from spoiled rib steaks.
• Optimized phage isolation and plating efficiency at lower temperatures (1-7°C).
• Identified 14 distinct phage lysotypes among the tested B. thermosphacta strains based on differential susceptibility patterns.

Conclusions:

• Phage typing is a rapid and sensitive method for differentiating B. thermosphacta strains.
• Isolated psychrotrophic phages can be utilized for epidemiological studies and strain differentiation in food microbiology.
• Further research into phage-host interactions can enhance food safety strategies.