Isolation and characterization of a novel phage P785, its combination with thermal processing for the biocontrol of Escherichia coli in milk

Escherichia coli is one of the most important foodborne pathogens. In food industry, heat treatment is the most commonly used means of sterilization. Bacteriophage is a new type of antibacterial agent. The combination of heat stable bacteriophage and heat treatment technology to control E. coli pollution in food is a new antibacterial method. A bacteriophage P785 capable of cleaving E. coli was isolated in this study. P785 belongs to the myxoviridae family. It could cleave 21 strains of bacteria, with a cleavage capacity of 83 PFU/cell, and the optimal multiple of infection (MOI) was 0.01. It has good tolerance to high temperature, pH, ultraviolet radiation (UV), and four organic reagents. No genes encoding virulence were found in the whole genome. When P785 (MOI = 10,000) was added to milk combined with heat treatment (55°C, 30 min), the number of host bacteria was less than 1 lg (CFU/mL) in 0–15 days under the storage condition of 4°C, and no host bacteria survived in 30 days. The results showed that P785 had a good killing effect on E. coli, and its combination with thermal processing could reduce the thermal processing temperature and prolong the shelf life of food.