rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Quantification of the antimicrobial substances produced by lactic acid bacteria used as an intervention to inhibit Escherichia coli O157:H7 and Salmonella in vitro and on fresh spinach (Spinacia oleracea)
  name:
    name part: Calix Lara, Thelma.
    role:
      role term: creator
  name:
    name part: Taylor, Thomas M
    role:
      role term: thesis advisor.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2012
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: remote
    extent: 1 online resource.
  abstract: The metabolic activity of bacterial microorganisms may influence the growth and metabolic activities of other microbes that are present in any specific niche. Lactic acid bacteria (LAB) are antagonistic to some microbial pathogens by the metabolic production of compounds with antimicrobial activity. Consequently, investigators have measured the effects of those antimicrobials to inhibit specific pathogens. However, the mode(s) of action of LAB against foodborne pathogens on products and/or in broth is not completely understood. Therefore, the objectives of this research were to (i) determine the LAB dose required for inhibition of Escherichia coli O157:H7 and Salmonella enterica in vitro and on spinach, and (ii) identify and quantify the major antimicrobial substances synthesized by LAB as a function of postinoculation storage conditions. Assays were performed at 7 degrees C under aerobic conditions. The foodborne pathogens dose responses were assessed in a liquid microbiological medium (in vitro) and on spinach leaf surfaces. Different levels of foodborne pathogens and LAB cultures were used. The addition of LAB cultures did not reduce E. coli O157:H7 or Salmonella enterica populations when performed in vitro. However, when LAB cultures were sprayed on the surfaces of spinach leaves at 8.0 log10 CFU/g, there were significant reductions on E. coli O157:H7 of 1.62 and 0.73 log10 CFU/g (after 3 days) and on Salmonella enterica of 1.85 and 0.71 log10 CFU/g (after 6 days) for treatments inoculated with an initial level of 2.0 and 4.0 log10 CFU/g, respectively. After quantification of the antimicrobial compounds synthesized by LAB cultures, they were correlated against the population growth of targeted pathogens. The highest Llactic acid (3.71 ± 0.14 micromoles/ml, day 12) and hydrogen peroxide (3.72 ± 3.34 microM, day 6) production were obtained from the in vitro sample inoculated with 8.0 log10 CFU/ml of LAB and 0.0 log10 CFU/ml of pathogens. The highest bacteriocin pr…
  note: by Thelma Calix Lara.
  note: "Major Subject: Food Science and Technology"
  note: Electronic resource.
  note: Doctor of Philosophy Texas A&M University 2011 http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10296
  note: Includes bibliographical references.
  note: Text (Dissertation)
  subject:
    topic: Major Food Science and Technology
  subject:
    topic: Spinach
  subject:
    topic: Salmonella
  subject:
    topic: Bacteriocin
  subject:
    topic: E. coli O157:H7
  subject:
    topic: Lactic acid bacteria
  identifier: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10296
  record info:
    record content source: TXA
    record creation date: 121009
    record change date: 20150922122117.0
    record identifier: in00002758022