title: Effects of exposure to poultry chemical decontaminants on the membrane fluidity of Listeria monocytogenes and Salmonella enterica strains.
abstract: There is a lack of work comparing the influence of various poultry chemical decontaminants on the membrane fluidity of pathogenic bacteria. In order to assess the possible role of physical membrane changes on bacterial adaptation to decontaminants, fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) was measured in Listeria monocytogenes and Salmonella enterica strains before and after growth in the presence of increasing sub-lethal concentrations of decontaminants (trisodium phosphate - TSP, acidified sodium chlorite - ASC, citric acid - CA and peroxyacids - PA). Higher (P<0.05) anisotropy values (lower membrane fluidity) were observed, both before and after exposure to decontaminants, in strains of L. monocytogenes (average 0.206+/-0.008) than in those of S. enterica (0.188+/-0.013). Cells exposed to sub-inhibitory concentrations of acid decontaminants (CA or PA) showed higher (P<0.05) anisotropy values and percentages of survival to acid stress than unexposed cells, suggesting that adaptation to these compounds is related to changes in membrane fluidity. Minimal changes in anisotropy values were observed after growth in presence of TSP or ASC. After treatment with strong concentrations of acid decontaminants (0.05 and 1% ASC, 5% and 10% CA, and 0.1 and 0.25% PA) the highest anisotropy values (highest membrane rigidity) were shown by cells previously grown with sub-inhibitory concentrations of CA or PA, suggesting that the synergistic effects of successive applications of various acids should be minimized. Because of the relationship between high membrane rigidity and high resistance to different stresses, the fact that it is essential to ensure adequate, inhibitory, CA or PA concentrations during poultry decontamination treatments is underlined.
authors.affiliation: Area de Nutrición y Bromatología, Departamento de Higiene y Tecnología de los Alimentos, Universidad de León, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Alonso-Hernando
authors.forename: Carlos
authors.initials: C
authors.lastname: Alonso-Calleja
authors.forename: Rosa
authors.initials: R
authors.lastname: Capita
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects*; D002712:Chlorides / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D003666:Decontamination / Q000379:methods; D004202:Disinfectants / Q000494:pharmacology*; D005454:Fluorescence Polarization; D006801:Humans; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000502:physiology; D008560:Membrane Fluidity / Q000187:drug effects*; D010463:Peracetic Acid / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D011200:Poultry; D019779:Salmonella enterica / Q000187:drug effects* / Q000502:physiology; D013312:Stress, Physiological
chemical_list: D002712:Chlorides; D004202:Disinfectants; D010710:Phosphates; D019343:Citric Acid; D010463:Peracetic Acid; C018279:sodium phosphate; C001599:chlorite