Bacteriophages, recovered frombeef cattle environment and specifically targeting Escherichia coli O157:H7, were examined for their\nphysiological andmorphological characteristics. Degree of bacterial lysis and host range of isolated bacteriophages was determined\nagainst 55 isolates of E. coli O157:H7.Morphology of phages was examined under transmission electron microscope. Phage growth\nparameters, particularly rate of adsorption, rise period, latent period, and burst size were also determined.The stability of isolated\nphages was tested at acidic and alkaline pH, at high temperatures, and in cold storage.Atotal of 7 phageswere isolatedwhich showed\nlytic activity against 50 out of 55 isolates of E. coli O157:H7. Based on the morphology, phages were classified into Myoviridae or\nSiphoviridae family. Phages had a rise period between 19 and 40 min, a short latent period between 12 and 30 min, and a large\nburst size (89ââ?¬â??631 virions per infected cell), indicating high lytic activity. Phages remained stable for 24 h at a wide pH (1ââ?¬â??11) and\ntemperature range (40ââ?¬â??60âË?Ë?C) and for 90 d in cold storage. Characterization of bacteriophages, with a diverse host range of E. coli\nO157:H7, could aid in the development of effective biocontrol strategies for this pathogen in the food industry.
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