title: Profiling of recovery efficiencies for three standard protocols (FDA-BAM, ISO-11290, and modified USDA) on temperature-injured Listeria monocytogenes.
abstract: There have been a number of studies conducted in order to compare the efficiencies of recovery rates, utilizing different protocols, for the isolation of L. monocytogenes. However, the severity of multiple cell injury has not been included in these studies. In the current study, L. monocytogenes ATCC 19112 was injured by exposure to extreme temperatures (60°C and -20°C) for a one-step injury, and for a two-step injury the cells were transferred directly from a heat treatment to frozen state to induce a severe cell injury (up to 100% injury). The injured cells were then subjected to the US Food and Drug Administration (FDA), the ISO-11290, and the modified United States Department of Agriculture (mUSDA) protocols, and plated on TSAyeast (0.6% yeast), PALCAM agar, and CHROMAgar Listeria for 24 h or 48 h. The evaluation of the total recovery of injured cells was also calculated based on the costs involved in the preparation of media for each protocol. Results indicate that the mUSDA method is best able to aid the recovery of heat-injured, freeze-injured, and heat-freeze-injured cells and was shown to be the most cost effective for heat-freeze-injured cells.
authors.affiliation: Centre of Excellence for Food Safety Research, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan, Malaysia. leehaiyen@gmail.com
authors.forename: Hai Yen
authors.initials: HY
authors.lastname: Lee
authors.forename: Lay Ching
authors.initials: LC
authors.lastname: Chai
authors.forename: Chai Fung
authors.initials: CF
authors.lastname: Pui
authors.forename: Woan Chwen
authors.initials: WC
authors.lastname: Wong
authors.forename: Shuhaimi
authors.initials: S
authors.lastname: Mustafa
authors.forename: Yoke Kqueen
authors.initials: YK
authors.lastname: Cheah
authors.forename: Zuraini
authors.initials: Z
authors.lastname: Mat Issa
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Nishibuchi
authors.forename: Son
authors.initials: S
authors.lastname: Radu
mesh_terms: D003080:Cold Temperature; D015169:Colony Count, Microbial / Q000191:economics / Q000379:methods* / Q000592:standards; D006358:Hot Temperature; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000302:isolation & purification; D050296:Microbial Viability; D014481:United States; D016885:United States Department of Agriculture; D014486:United States Food and Drug Administration