Antimicrobial properties of chosen phenolic compounds against Escherichia coli O157:H7

摘要

The aim of this research was to examine an antimicrobial activity of salts of phenolic acids against Escherichia coli O157:H7 ATCC 8739 and to assess their lowest minimum inhibitory concentrations (MICs). E. coli O157:H7 is a pathogen producing verotoxins which provoke hemorrhagic diarrhea at people. There is a demand for the effective natural methods eliminating E. coli O157:H7 from food. The following salts were tested: lithium, sodium and potassium salts of syringic, meta-anisic and vanillic acids. The 1%, 2%, 3%, 4% and 5% water solutions of each substance were prepared. Agar-well diffusion method was applied. The Petri dishes were incubated at 35°C for 24 h. At the end of the incubation period, inhibition zones which appeared on the medium Petri dishes were calculated in millimeters. It was proved that a lithium salt of syringic acid was the most effective towards E. coli O157:H7, while a potassium salt of syringic acid and a potassium salt of vanillic acid were slightly less effective, and a lithium salt of vanillic acid, a sodium salt of vanillic acid and a potassium salt of m-anisic acid indicated comparatively lower antimicrobial activity, and lithium and sodium salts of m-anisic acid were the least effective against the pathogen. The salts of phenolic acids possessing different structural features showed various characteristics against foodborne pathogens. Such research results indicate that phenolic acids and their salts can be a potential bio-alternative for chemical food preservation.