title: Inactivation of Listeria monocytogenes and Escherichia coli O157:H7 biofilms by micelle-encapsulated eugenol and carvacrol.
abstract: Carvacrol and eugenol were encapsulated in micellar nonionic surfactant solutions to increase active component concentrations in the aqueous phase and used to treat two strains of Listeria monocytogenes (Scott A and 101) and two strains of Escherichia coli O157:H7 (4388 and 43895) grown as biofilms in a Centers for Disease Control and Prevention reactor. L. monocytogenes biofilms were grown in two different growth media, 1:20 TSB and Modified Welshimer's broth (MWB), while E. coli O157:H7 was grown in M9. In general, L. monocytogenes strains were more resistant to both micelle-encapsulated antimicrobials than E. coli O157:H7 strains. The two antimicrobials were equally effective against both strains of E. coli O157:H7, decreasing viable counts by 3.5 to 4.8 log CFU/cm(2) within 20 min. For both bacteria, most of the bactericidal activity took place in the first 10 min of antimicrobial exposure. Biofilm morphology and viability were assessed by the BacLight RedoxSensor CTC Vitality kit and confocal scanning laser microscopy, revealing an increasing number of dead cells when biofilms were treated with sufficiently high concentrations of carvacrol- or eugenol-loaded micelles. This study demonstrates the effectiveness of the application of surfactant-encapsulated essential oil components on two pathogen biofilm formers such as E. coli O157:H7 and L. monocytogenes grown on stainless steel coupons.
authors.affiliation: Department of Food Science, University of Massachusetts, 100 Holdsworth Way, Amherst, Massachusetts 01003, USA.
authors.forename: D
authors.initials: D
authors.lastname: Pérez-Conesa
authors.forename: J
authors.initials: J
authors.lastname: Cao
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: McLandsborough
authors.forename: J
authors.initials: J
authors.lastname: Weiss
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000254:growth & development; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D000081007:Cymenes; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D005054:Eugenol / Q000494:pharmacology*; D005506:Food Contamination / Q000517:prevention & control*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods; D006801:Humans; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D008823:Micelles; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D039821:Monoterpenes / Q000494:pharmacology*; D013193:Stainless Steel
chemical_list: D000900:Anti-Bacterial Agents; D000081007:Cymenes; D008823:Micelles; D039821:Monoterpenes; D013193:Stainless Steel; D005054:Eugenol; C073316:carvacrol