Efficacy of Escherichia coli O157:H7 Phage Φ241 in Model Food Systems

Escherichia coli O157:H7 has been an important foodborne pathogen causing severe disease in humans worldwide. It is challenging to control E. coli O157:H7 due to its intrinsic acid resistance, ability to survive in various environments, and the emergence of antimicrobial resistance. Recent research showed that phages are promising antibacterial agents. A phage (Φ241) infecting 48 E. coli O157:H7 strains from various sources was previously isolated from an industrial cucumber fermentation at pH 3.7 and 5% NaCl. The efficacy of phage Φ241 infection was evaluated in this study in four representative model food systems (beef broth, cucumber juice, cucumber juice supplemented with NaCl, and apple juice). Pronounced differences in phage effectiveness were found in the tested food systems, and impacted by pH, salinity, and multiplicity of infection. The potential of this phage is evident in beef broth and cucumber juice, where 4- to 6-log reduction in host concentration was achieved within 3 to 5 h. However, apple juice (pH 3.55) completely inhibited host growth and phage infection. Overall, the study shows the high potential of Φ241 as an antibacterial agent to improve food safety. Futur