Physiological response of Saccharomyces cerevisiae to citral combined with thermal treatment

Tabanelli, Giulia; Montanari, Chiara; Arioli, Stefania; Magnani, Michael; Patrignani, Francesca; Lanciotti, Rosalba; Mora, Diego; Gardini, Fausto

doi:10.1016/j.lwt.2018.12.006

Cited by 7 publications

(7 citation statements)

References 36 publications

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“…The correlation coefficients for the FISH-FCM and the PCA count results for the different samples were greater than 0.9, showing an obvious positive correlation. Additionally, many studies have shown that the FCM method accurately quantifies the total number of bacteria, fungi or live/dead bacteria in samples (Van Nevel et al 2017;Ou et al 2019;Tabanelli et al 2019). Therefore, the FISH-FCM method established in this experiment can precisely count lactic acid bacteria and yeast in dairy products under the conditions of definite fluorescence in situ hybridisation.…”

Section: Comparison Of Different Methods For Counting Lactic Acid Bac...mentioning

confidence: 89%

Establishment of a rapid counting method for lactic acid bacteria and yeast in dairy products

Li,

Wang,

Wang

2024

Int J of Dairy Tech

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The plate count agar (PCA) method is a common technique used to count microorganisms in dairy products, but this method is time‐consuming and highly selective by the medium. This study adopted Lab158 and PF2 as the universal probes for hybridising lactic acid bacteria and yeasts, respectively, and investigated the effects of fixation time, hybridisation time, hybridisation temperature, probe concentration and propidium iodide (PI) concentration on hybridisation efficiency in the samples. The results showed that the highest hybridisation efficiency for lactic acid bacteria and yeast, along with the best double staining results, was observed under the following conditions: a fixation time of 80 min, a hybridisation time of 180 min, a hybridisation temperature of 48°C, a probe volume of 5 μL for lactic acid bacteria and 3 μL for yeast, and a PI volume of 5 μL for lactic acid bacteria and 3 μL for yeast. The fluorescence in situ hybridisation‐flow cytometry (FISH‐FCM) and PCA counting results showed a significant positive correlation (r > 0.9). The FISH‐FCM and PCA counting results showed a significant positive correlation (r > 0.9). The FISH‐FCM counting method can serve as a quick and accurate method for the counting of lactic acid bacteria and yeast in dairy products.

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Section: Comparison Of Different Methods For Counting Lactic Acid Bac...mentioning

confidence: 89%

Establishment of a rapid counting method for lactic acid bacteria and yeast in dairy products

Li,

Wang,

Wang

2024

Int J of Dairy Tech

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“…The cells were stained with SYBR-Green I (1X), propidium iodide (PI) 7.5 μM and DiBAC 4 (3) (Bis-(1,3-Dibutylbarbituric Acid) Trimethine Oxonol) 3.0 μM as reported by Tabanelli et al [ 16 ]. The data obtained were analyzed using the BD ACCURITM C6 software version 1.0 (BD Biosciences, Milan, Italy).…”

Section: Methodsmentioning

confidence: 99%

Metabolism of Lactobacillus sakei Chr82 in the Presence of Different Amounts of Fermentable Sugars

Barbieri

Laghi

Gardini

et al. 2020

Foods

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Lactobacillus sakei is widely used as a starter culture in fermented sausages since it is well adapted to meat environments and able to maintain high viability thanks to secondary pathways activated when hexoses are depleted (i.e., metabolism of pentoses and amino acids). In this study, a commercial strain of L. sakei was inoculated in a defined medium with ribose or glucose as the carbon source, at optimal or reduced concentrations, to evaluate its different physiological and metabolic responses in relation to different growth conditions. The results obtained with different approaches (HPLC, 1H-NMR, flow cytometry) evidenced different growth performances, amino acid consumptions and physiological states of cells in relation to the carbon source as an active response to harsh conditions. As expected, higher concentrations of sugars induced higher growth performances and the accumulation of organic acids. The low sugars amount induced the presence of dead cells, while injured cells increased with ribose. Arginine was the main amino acid depleted, especially in the presence of higher ribose, and resulted in the production of ornithine. Moreover, the 1H-NMR analysis evidenced a higher consumption of serine at the optimal sugars concentration (pyruvate production). This information can be helpful to optimize the use of these species in the industrial production of fermented sausages.

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“…The strain Saccharomyces cerevisiae SPA belonging to the collection of the Department of Agricultural and Food Sciences (University of Bologna) was used in this study. It was isolated from spoiled soft drinks (Ndagijimana et al, 2004) and in previous trials showed resistance to thermal and non-thermal treatments (Patrignani et al, 2013; Tabanelli et al, 2019). The strain was stored at −80°C and, before the experiments, refreshed twice in Sabouraud dextrose medium (SAB; Oxoid, Basingstoke, UK) for 48 h at 28°C.…”

Section: Methodsmentioning

confidence: 99%

“…Cell suspensions collected immediately after treatments and during recovery were analyzed with a flow cytometer Accuri C6 (BD Biosciences, Milan, Italy), using setting parameters, emission filters and thresholds according to Arioli et al (2019). The cells were stained with SYBR-Green I (1X), propidium iodide (PI) 7.5 μM, and DiBAC 4 (3) [Bis-(1,3-Dibutylbarbituric Acid) Trimethine Oxonol] 3.0 μM as reported by Tabanelli et al (2019), and data obtained were analyzed using the BD ACCURITM C6 software version 1.0 (BD Biosciences, Milan, Italy).…”

Section: Methodsmentioning

confidence: 99%

“…Indeed, the characteristics of these products (low pH and high sugar amounts) give a competitive advantage to this species towards other microbial groups. To avoid yeast proliferation, that would cause ethanol and CO 2 accumulation, with consequent package blowing, thermal treatments have been traditionally applied (Tabanelli et al, 2019). However, because of their negative side-effects in terms of sensorial and nutritional profiles, PEF has been proposed as a feasible non-thermal technology for beverage stabilization (Mathys et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Heat-Assisted Pulsed Electric Field Treatment for the Inactivation of Saccharomyces cerevisiae: Effects of the Presence of Citral

et al. 2019

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Pulsed electric field (PEF) treatment is a non-thermal technology that has shown good potential for microbial inactivation. However, in many cases, it cannot be sufficient to avoid microbial proliferation, and the combination with other stabilizing technologies is needed. In the framework of the hurdle concept, several researches have been focused on the use of PEF in combination with heat and/or antimicrobials to increase its efficacy. This study investigated the inactivation effect of PEF on a strain of Saccharomyces cerevisiae (isolated from spoiled beverages) in a model system (growth medium). The efficacy of PEF treatment was evaluated in relation to different variables, such as electric field strength (25 and 50 kV/cm), treatment time (from 1 to 5 s), initial inoculum level (4 or 6 log cfu/ml), preheating at 50°C, medium pH (4 or 6), and addition of citral at sublethal concentration (i.e., half of minimum inhibiting concentration). The data from plate counting, modeled with the Weibull equation, showed that one of the main factors affecting yeast inactivation was the preheating of the suspension at 50°C. Indeed, higher cell load reductions were obtained with heat-assisted PEF, especially in the presence of citral. The effect of initial cell load was negligible, while pH affected yeast inactivation only without preheating, with higher death kinetics at pH 6. Flow cytometry (FCM) analysis confirmed higher mortality under these conditions. However, the occurrence of injured cells, especially in samples treated at pH 4, was observed. The ability of these cells to recover from the damages induced by treatments was affected by both citral and preheating. The synergic effects of PEF, preheating, and citral were likely due to the increase of membrane permeability (especially at pH 6), as the primary target of electroporation, which favored the solubilization of citral in the cell membrane, enhancing the efficacy of the whole process. The multi-analytical approach (traditional plate counting and FCM) allowed defining parameters to increase PEF efficacy against S. cerevisiae . Moreover, FCM, able to discriminate different physiological states of the yeast population, was helpful to better clarify the action mechanism and the potential recovery of cells after treatment.

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Physiological response of Saccharomyces cerevisiae to citral combined with thermal treatment

Cited by 7 publications

References 36 publications

Establishment of a rapid counting method for lactic acid bacteria and yeast in dairy products

Establishment of a rapid counting method for lactic acid bacteria and yeast in dairy products

Metabolism of Lactobacillus sakei Chr82 in the Presence of Different Amounts of Fermentable Sugars

Heat-Assisted Pulsed Electric Field Treatment for the Inactivation of Saccharomyces cerevisiae: Effects of the Presence of Citral

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