Targeted biocontrol of Escherichia coli O157:H7 biofilms in food environments using the novel bacteriophage CAU_ECP01.

Abstract

Escherichia coli O157:H7 is a major foodborne pathogen characterized by its low infectious dose, strong environmental persistence, and robust biofilm-forming ability on food-contact surfaces. In this study, CAU_ECP01 is isolated, a novel strictly lytic bacteriophage specific to E. coli O157:H7, from a wastewater treatment facility in South Korea. Whole-genome sequencing of phage CAU_ECP01 revealed a double-stranded DNA genome of 169,126 bp and a 37.7% GC content. No virulence- or antibiotic resistance-related genes were detected. Phage CAU_ECP01 exhibited rapid adsorption (94% within 30 min) and remained stable over a wide range of temperature (0-60 °C) and pH (4-10). In planktonic cultures grown in LB broth at 37 °C, phage treatment at an MOI of 100 prevented detectable bacterial regrowth for 22 h, while even a low MOI of 0.1 resulted in a significant reduction in bacterial proliferation. On stainless steel and high-density polyethylene surfaces, phage CAU_ECP01 reduced pre-formed E. coli O157:H7 biofilms by 2.0 and 1.9 log CFU/cm2, respectively (P < 0.05). When applied to inoculated beef and lettuce stored at 25 °C, phage treatment (MOI 100) achieved significant reductions of 1.2 and 2.3 log CFU/g, respectively (P < 0.05). Hunter color and texture profile analysis revealed no significant differences between treated and untreated samples (P > 0.05), indicating no adverse effects on product quality. Overall, these findings demonstrate that phage CAU_ECP01 is a potent, stable, and safe biocontrol candidate capable of effectively mitigating E. coli O157:H7 contamination on food-contact surfaces, meat, and fresh produce, highlighting its potential application in modern food processing environments.