title: Comparison of inactivation pathways of thermal or high pressure inactivated Lactobacillus rhamnosus ATCC 53103 by flow cytometry analysis.
abstract: The effect of thermal and pressure treatments on Lactobacillus rhamnosus ATCC 53103 was evaluated by flow cytometric analysis in conjunction to standard cultivation techniques. A double staining technique with fluorochromes carboxyfluorescein diacetate (cFDA) and propidium iodide (PI) revealed that depending on temperature regime used heat-killed cells had different fluorescence behaviors. Cells killed at 60 degrees C were not stained at all whereas heat treatment at 75 degrees C resulted in a single population entirely labelled by PI. These findings indicated that thermal-induced cell death was achievable with or without membrane degradation. Hydrostatic pressures beyond 400 MPa inactivated L. rhamnosus ATCC 53103 in a different way. It was observed that the irreversible damage of the membrane-bound transport systems could be largely accounted for the cause of high pressure-induced cell death.
authors.affiliation: Food Biotechnology and Food Process Engineering, Berlin University of Technology, Königin-Luise-Str. 22, D-14195 Berlin, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Ananta
authors.forename: D
authors.initials: D
authors.lastname: Knorr
mesh_terms: D002469:Cell Separation; D015169:Colony Count, Microbial; D005434:Flow Cytometry; D005452:Fluoresceins / Q000493:pharmacokinetics; D005456:Fluorescent Dyes / Q000493:pharmacokinetics*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D006358:Hot Temperature; D006874:Hydrostatic Pressure; D007700:Kinetics; D052201:Lacticaseibacillus rhamnosus / Q000254:growth & development*; D019936:Probiotics; D011419:Propidium / Q000493:pharmacokinetics
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; C027780:carboxyfluoresceindiacetate; D011419:Propidium