title: Effects of preparation method, age, and plating technique of thin agar layer media on recovery of Escherichia coli O157:H7 injured by sodium chloride.
abstract: The thin agar layer (TAL) method was experimentally tested to determine its ability to recover Escherichia coli O157:H7 injured by sodium chloride (NaCl). Cells grown in Brain Heart Infusion broth with 0%, 5%, or 7.5% (w/v) NaCl were spread and spiral plated onto Tryptic Soy agar (TSA), MacConkey Sorbitol agar (MSA), and TSA/MSA TAL combinations. Generally, TSA recovered more injured cells than TAL (p < or =0.05), and TAL recovered more cells than MSA (p < or =0.05). Preparation mode (two vs. three layers) and age (0, 1, or 7 days) of TAL had negligible effect on resuscitation of injured cells (p > 0.05). TAL, which is conventionally used to recover heat, cold, and acid-injured foodborne pathogens, may be used to recover NaCl-injured E. coli O157:H7.
authors.affiliation: Department of Population Health and Reproduction, University of California-Davis, Davis, CA 95616, USA. mnhajmeer@ucdavis.edu
authors.forename: M N
authors.initials: MN
authors.lastname: Hajmeer
authors.forename: D Y
authors.initials: DY
authors.lastname: Fung
authors.forename: J L
authors.initials: JL
authors.lastname: Marsden
authors.forename: G A
authors.initials: GA
authors.lastname: Milliken
mesh_terms: D000143:Acids; D000362:Agar; D001431:Bacteriological Techniques / Q000379:methods*; D018929:Cell Culture Techniques / Q000379:methods*; D015169:Colony Count, Microbial; D003470:Culture Media / Q000737:chemistry; D019453:Escherichia coli O157 / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology*; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D000143:Acids; D003470:Culture Media; D012965:Sodium Chloride; D000362:Agar