Piper betle Leaf Extract Inhibits Escherichia coli O157:H7 Biofilms and Prevents Bacterial Adhesion on Beef during Storage

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is one of a major foodborne pathogen concern worldwide.This study aimed to investigate the antibacterial, antibiofilm, and anti-adhesion properties of Piper betle extract against EHEC O157:H7 during storage.The suspected isolates were identified as EHEC O157:H7 through 16S rRNA sequence alignment, showing 100% homology.The extract exhibited antibacterial activity against all isolates, with similar MIC and MBC values as 0.5-1.0mg/mL.The extract at 1/2MIC significantly inhibited biofilm formation in all isolates with 66-75% inhibition (P<0.05).Established biofilms were disrupted by 63-76% when treated with Piper betle extract at 8MIC.Adhered cells on beef were reduced by 3 logs with the extract at 8MIC within 3 and 6 h at 37C and 4C, respectively.A significant reduction in bacterial adhesion on beef was observed when treated with the extract at 8 and 4MIC during 7-day storage at -18C.At 7-day storage, beef treated with 8MIC did not show a significant difference in hardness, cohesiveness, springiness, gumminess, and chewiness of the beef, compared with the control.These findings suggest that Piper betle leaf extract inhibits E. coli O157:H7 biofilms and prevents the bacterial adhesion on beef during storage.