Resuscitation and growth kinetics of sub-lethally injured Listeria monocytogenes strains following fluorescence activated cell sorting (FACS)

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dc.contributor.author Sibanda, Thulani
dc.contributor.author Buys, E.M. (Elna Maria)
dc.date.accessioned 2017-11-10T11:33:11Z
dc.date.issued 2017-10
dc.description.abstract This study investigated the effect of acid (pH 4.2), osmotic (10% NaCl) and heat (55 °C for 30 min) stress induced injury on Listeria monocytogenes strains ATCC19115, 69, 159/10 and 243 using differential plating and flow cytometry coupled with membrane integrity indicators, thiazole orange (TO) and propidium iodide (PI) staining. Growth kinetics of injured cells sorted by fluorescence activated cell sorting (FACS) were studied at 4, 25 and 37 °C. The percentage of cell injury detectable by both flow cytometry and differential plating varied significantly among strains and stress treatments (p < 0.0001). Based on flow cytometry and TO/PI staining, acid stress caused the highest level of injury followed by heat and osmotic stress. Following cell sorting, acid and osmotic stress injured cells were capable of resuscitation and re-growth while heat injured cells (except for strain 69) were incapable of re-growth despite having a high level of membrane intact cells. The lag phase duration (λ) of sorted stress injured cells resuscitated in brain heart infusion (BHI) broth was significantly influenced by strain variations (p < 0.0001), stress treatments (p = 0.007) and temperature of resuscitation (p ≤ 0.001). Following repair, the maximum specific growth rate (μmax) of resuscitated cells was not different from untreated control cells regardless of strain differences and stress treatments. Only temperature had a significant effect (p < 0.0001) on growth rate. Sorted cells were also capable of growth at 4 °C, with the time to detectable growth (≥ 1.40 Log10 CFU ml− 1) ranging from 3 to 15 days. Overall, re-growth potential of sorted cells showed that while membrane integrity was a good indicator of cell injury and viability loss for acid and osmotic stress, it was not a sufficient indicator of heat stress injury. Once injured cells repair the cellular damage, their growth rate is not different from non-injured cells regardless of form of stress and strain differences. Thus highlighting the potential food safety risks of stress injured L. monocytogenes cells. en_ZA
dc.description.department Food Science en_ZA
dc.description.embargo 2018-10-30
dc.description.librarian hj2017 en_ZA
dc.description.sponsorship The South African National Research Foundation (NRF) Centre of Excellence in Food Security (Project 140203: Wastage and Loss). en_ZA
dc.description.uri http://www.elsevier.com/locate/foodres en_ZA
dc.identifier.citation Sibanda, T. & Buys, E.M. 2017, 'Resuscitation and growth kinetics of sub-lethally injured Listeria monocytogenes strains following fluorescence activated cell sorting (FACS)', vol. 100, part 2, pp. 150-158. en_ZA
dc.identifier.issn 0963-9969 (print)
dc.identifier.issn 1873-7145 (online)
dc.identifier.other 10.1016/j.foodres.2017.08.020
dc.identifier.uri http://hdl.handle.net/2263/63097
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2017 Elsevier Ltd. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Food Research International. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Food Research International, vol. 100, pp. 150-158, 2017. doi : 10.1016/j.foodres.2017.08.020. en_ZA
dc.subject Listeria monocytogenes (Lm) en_ZA
dc.subject Stress en_ZA
dc.subject Injury en_ZA
dc.subject Flow cytometry en_ZA
dc.subject Cell sorting en_ZA
dc.subject Resuscitation en_ZA
dc.subject Growth kinetics en_ZA
dc.subject Membrane integrity en_ZA
dc.subject Maximum specific growth rates en_ZA
dc.subject Lag phase duration en_ZA
dc.subject Fluorescence activated cell sorting en_ZA
dc.subject Brain heart infusions en_ZA
dc.subject Strain en_ZA
dc.subject Repair en_ZA
dc.subject Plants (botany) en_ZA
dc.subject Osmosis en_ZA
dc.subject Listeria en_ZA
dc.subject Growth rate en_ZA
dc.subject Fluorescence en_ZA
dc.subject Diseases en_ZA
dc.subject Cytology en_ZA
dc.subject Cells en_ZA
dc.title Resuscitation and growth kinetics of sub-lethally injured Listeria monocytogenes strains following fluorescence activated cell sorting (FACS) en_ZA
dc.type Postprint Article en_ZA


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