title: Salmonella enterica serovar Typhimurium and Listeria monocytogenes acid tolerance response induced by organic acids at 20 degrees C: optimization and modeling.
abstract: An acid tolerance response (ATR) has been demonstrated in Listeria monocytogenes and Salmonella enterica serovar Typhimurium in response to low pH poised (i.e., adapted) with acetic or lactic acids at 20 degrees C and modeled by using dynamic differential equations. The ATR was not immediate or prolonged, and optimization occurred after exposure of L. monocytogenes for 3 h at pH 5.5 poised with acetic acid and for 2 h at pH 5.5 poised with lactic acid and after exposure of S. enterica serovar Typhimurium for 2 h at pH 5.5 poised with acetic acid and for 3 h at pH 5.5 poised with lactic acid. An objective mechanistic analysis of the acid inactivation data yielded estimates of the duration of the shoulder (t(s)), the log-linear decline (k(max)), and the magnitude of a critical component (C). The magnitude of k(max) gave the best agreement with estimates of conditions for optimum ATR induction made from the raw data.
authors.affiliation: Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom. elizabeth.greenacre@bbsrc.ac.uk
authors.forename: E J
authors.initials: EJ
authors.lastname: Greenacre
authors.forename: T F
authors.initials: TF
authors.lastname: Brocklehurst
authors.forename: C R
authors.initials: CR
authors.lastname: Waspe
authors.forename: D R
authors.initials: DR
authors.lastname: Wilson
authors.forename: P D G
authors.initials: PD
authors.lastname: Wilson
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology*; D003470:Culture Media; D018869:Heat-Shock Response; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019344:Lactic Acid / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000502:physiology; D008954:Models, Biological; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000502:physiology; D013696:Temperature
chemical_list: D003470:Culture Media; D019344:Lactic Acid; D019342:Acetic Acid