Contaminated beef is a prominent source of foodborne pathogens such as Escherichia coli O177. Susceptibility of nine multi-drug resistant E. coli O177 strains against eight individual phages and six phage cocktails was assessed using polystyrene microplate titer plate. Further, 180 beef samples were independently inoculated with E. coli O177 cells in triplicates and treated with eight individual phages and six phage cocktails to determine their efficacy in inhibiting bacteria growth at 4 °C over a 7-day incubation period. Results revealed that all E. coli O177 strains were susceptible to the phages. A significant log reduction in viable E. coli O177 cell counts was observed on beef samples upon phage treatment over the 7-day incubation period. Two individual phages and three phage cocktails reduced E. coli cell counts to levels below the detection limit (1.0 log₁₀ CFU/g). Log reduction of viable E. coli cell counts ranged from 2.10 to 7.81 CFU/g for individual phages and from 2.86 to 7.81 CFU/g for cocktails. Individual phages and phage cocktails inhibited E. coli O177 biofilm formation with phage cocktails showing high efficacy. Furthermore, phage cocktails showed greater efficacy in destroying pre-formed biofilm than individual phages. Based on these findings, we concluded that phage cocktails developed in this study could be used to reduce E. coli O177 contamination and extend the shelf-life of stored raw beef.

被污染的牛肉是食源性病原体（如大肠杆菌O177 ）的重要来源。使用聚苯乙烯微孔板滴定板评估了九种耐多药大肠杆菌O177菌株对八种噬菌体和六种噬菌体混合物的敏感性。此外，将180份牛肉样品一式三份分别接种大肠杆菌O177细胞，并用8个单独的噬菌体和6个噬菌体混合物进行处理，以确定它们在7天的培养期内抑制4°C细菌生长的功效。结果表明，所有大肠杆菌O177菌株均对噬菌体敏感。活大肠杆菌的对数显着减少在7天的孵育期内，经噬菌体处理后，在牛肉样品上观察到O177细胞计数。两个单独的噬菌体和三个噬菌体混合物将大肠杆菌细胞计数降低到检测限以下（1.0 log ₁₀  CFU / g）。对于单个噬菌体，活的大肠杆菌细胞计数的对数减少范围为2.10至7.81 CFU / g，而对于鸡尾酒，则为2.86至7.81 CFU / g。单个噬菌体和噬菌体混合物抑制大肠杆菌O177生物膜的形成，噬菌体混合物显示出高功效。此外，噬菌体混合物显示出比单个噬菌体更强的破坏预先形成的生物膜的功效。基于这些发现，我们得出结论，本研究开发的噬菌体混合物可用于减少大肠杆菌 O177污染并延长了生牛肉的保质期。