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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Saarela, Maria
in Cooperation with on an Cooperation-Score of 37%
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Publications (3/3 displayed)
- 2015Study into the Functional and Luxury Food Value Chains in Asia and Australia including Foresights project
- 2006Control of biofilm growth through photodynamic treatments combined with chemical inhibitors: In vitro evaluation methods
- 2004Application of microplate scale fluorochrome staining assay for assessment of viability and stability of probiotic Bifidobacterium sp.
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document
Application of microplate scale fluorochrome staining assay for assessment of viability and stability of probiotic Bifidobacterium sp.
Abstract
Probiotic cultures encounter harsh conditions during production and inthe GI-tract. There is a need for rapid and reliable methods predictingsurvival and activity of the probiotic cultures in various applications. Inthis study we describe a fluorescence staining assay for the determination ofviability of Bifidobacterium cells in microplate scale. LIVE/DEAD BacLightBacterial Viability Kit (SYTO9 and propidium iodide) was utilized forviability testing of fresh and freeze-dried Bifidobacterium cells and thefluorescence intensity was detected by a microplate fluorometer. Validation ofthe microplate scale assay was performed by comparing results to colonyforming units, fluorescence microscopy and spectroscopy. Fresh andfreeze-dried B. animalis cultures treated in acidic conditions (pH 2.5 and pH3.0 alone and in combination with pepsin) or stored at different temperatureswere used to study the applicability of the microplate assay for viabilityassessment of stressed cells. To reveal changes in membrane functions duringacid treatment, DIBAC4 (a potentiometric fluorochrome) was additionally usedfor the analysis of the acid treated cells. In general, the results obtainedwith the microplate assay were comparable with plate count analysis andfluorescence microscopy. Microplate assay with viability stains gave anestimate of the viability of the probiotic preparations (detection level 106cfu and the assay was applicable also for acid-treated cells. In the acidtolerance test, B. animalis was sensitive to pH 2.5, although pepsin hadclearly protective effect in acidic conditions. Potentiometric measurementswith DiBAC4 fluorochrome indicate that acidic conditions causedhyperpolarization of the cell membrane in B. animalis cells. Benefits from thefluorochromic viability assays are that changes in cell state in probioticpreparations can be estimated earlier compared to the results obtained withtraditional cultivation methods.