title: Inhibitory properties of lithium, sodium and potassium o-, m- and p-coumarates against Escherichia coli O157:H7.
abstract: BACKGROUND
  The aim of this paper was to assess the inhibitory properties of salts of phenolic acids against Escherichia coli O157:H7 ATCC 8739. Escherichia coli O157:H7 is a pathogen which is able to produce verotoxins provoking hemorrhagic diarrhea in humans. There is a strong need for the effective natural methods eliminating E. coli O157:H7 from food. Methodology. The following salts were tested: sodium, potassium and lithium salts of ortho-coumaric, meta-coumaric and para-coumaric acids. The 1%, 2%, 3%, 4% and 5% water solutions of each substance were prepared. Agar-well diffusion method was applied. 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. Results. It was found that lithium salt of o-coumaric acid, potassium salt of o-coumaric acid, lithium salt of m-coumaric acid and sodium salt of m-coumaric acid were most effective towards E. coli O157:H7, while potassium salt of m-coumaric acid, a sodium salt of p-coumaric acid were slightly less effective and lithium salt of p-coumaric acid did not possess any antimicrobial activity. Conclusion. The salts of phenolic acids having various structural features showed different characteristics towards foodborne pathogens. Such findings indicate that phenolic acids and their salts may be a potential bio-alternative for chemical food pres.
  
  
  METHODS
  nd. The aim of this paper was to assess the inhibitory properties of salts of phenolic acids against Escherichia coli O157:H7 ATCC 8739. Escherichia coli O157:H7 is a pathogen which is able to produce verotoxins provoking hemorrhagic diarrhea in humans. There is a strong need for the effective natural methods eliminating E. coli O157:H7 from food. Methodology. The following salts were tested: sodium, potassium and lithium salts of ortho-coumaric, meta-coumaric and para-coumaric acids. The 1%, 2%, 3%, 4% and 5% water solutions of each substance were prepared. Agar-well diffusion method was applied. 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.
  
  
  RESULTS
  It was found that lithium salt of o-coumaric acid, potassium salt of o-coumaric acid, lithium salt of m-coumaric acid and sodium salt of m-coumaric acid were most effective towards E. coli O157:H7, while potassium salt of m-coumaric acid, a sodium salt of p-coumaric acid were slightly less effective and lithium salt of p-coumaric acid did not possess any antimicrobial activity.
  
  
  CONCLUSIONS
  The salts of phenolic acids having various structural features showed different characteristics towards foodborne pathogens. Such findings indicate that phenolic acids and their salts may be a potential bio-alternative for chemical food preservation.
authors.affiliation: Food Technology and Food Service Institute, State College of Computer Science and Business Administration in Łomża, Poland.
authors.forename: Milena Alicja
authors.initials: MA
authors.lastname: Stachelska
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003373:Coumaric Acids / Q000494:pharmacology*; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods; D006801:Humans; D008094:Lithium / Q000494:pharmacology*; D010636:Phenols / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D011422:Propionates; D012492:Salts / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D003373:Coumaric Acids; D010636:Phenols; D011422:Propionates; D012492:Salts; C043332:3-coumaric acid; D008094:Lithium; D012964:Sodium; C495469:p-coumaric acid; D011188:Potassium
keywords: Escherichia coli O157:H7; antimicrobial activity; phenolic salts