Influence of culture conditions on the technological properties of Carnobacterium maltaromaticum CNCM I-3298 starters

The aim of this study is to investigate the effect of a broad spectrum of culture conditions on the acidification activity and viability of Carnobacterium maltaromaticum CNCM I‐3298, the main technological properties that determine the shelf‐life of biological time‐temperature integrator (TTI) labels. Cells were cultivated at different temperatures (20–37°C) and pH (6–9·5) according to a modified central composite design and harvested at increasing times up to 10 h of stationary phase. Acidification activity and viability of freeze‐thawed concentrates were assessed in medium mimicking the biological label. Acidification activity was influenced by all three culture conditions, but pH and harvest time were the most influential. Viability was not significantly affected by the tested range of culture conditions.Carnobacterium maltaromaticum CNCM I‐3298 must be cultivated at 20°C, pH 6 and harvested at the beginning of stationary phase to exhibit fastest acidification activities. However, if slower acidification activities are pursued, the recommended culture conditions are 30°C, pH 9·5 and a harvest time between 4–6 h of stationary phase. Quantifying the impact of fermentation temperature, pH and harvest time has led to a predictive model for the production of biological TTI covering a broad range of shelf‐lives

Mapping the physiological states of Carnobacterium maltaromaticum obtained” by applying stressful fermentation conditions

This work received funding from the European Union´s Horizon 2020 research and innovation programme under grant agreement No 777657Mapping the physiological states of Carnobacterium maltaromaticum obtained” by applying stressful fermentation conditions. 4. Microbial Stress: from systems to molecules and bac

Freeze-Drying of Lactic Acid Bacteria: A Stepwise Approach for Developing a Freeze-Drying Protocol Based on Physical Properties

International audienceFreeze-drying or lyophilization has become a reference process for preserving lactic acid bacteria. The development of stable freeze-dried lactic acid bacteria (LAB) requires maintaining the biological activity of the cells and the macroscopic porous structure while increasing the efficiency of the manufacturing process. Physical properties of protective solutions such as glass transition and collapse temperature, are key elements not only for process optimization but also for the stability of freeze-dried LAB. This chapter provides a stepwise approach for developing a protective formulation for long term preservation of LAB and an efficient freeze-drying process. Methods for determining glass transition and collapse temperatures of protective solutions and cell suspensions, as well as water activity and water content of freeze-dried products are described

Complementary analytical approaches improving knowledge on lactic acid bacteria cryoresistance

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 777657Complementary analytical approaches improving knowledge on lactic acid bacteria cryoresistance. 56. Annual Meeting of the Society for Cryobiolog

Application of Lactic Acid Bacteria in Time-Temperature Integrators

International audienceBiological Time-Temperature Integrators (TTI) offer a novel approach for improving food safety and preventing spoilage. These smart tools relay, by an irreversible color shift, the cumulative effect of time and temperature on the microbial quality of food they are attached to. Among various types of TTI developed to date, biological TTI have the advantage of reproducing microbiological spoilage reactions that take place in food. They are based on the pH decline of a medium contained within the label, resulting from lactic acid bacteria (LAB) growth and acidification. When developing LAB-based TTI, careful LAB strain selection, research, and development efforts on TTI production are necessary to closely match the behavior of both spoilage and pathogenic microorganisms that grow during the storage of perishable foods. Covering a wide range of time-temperature profiles is a challenging goal involving research in different domains (microbiology, food science, modelling, etc.). This chapter describes the design and working principle of LAB-based TTI, how they are parametrized to be able to track a wide range shelf-lives and how their performance is evaluated. Current applications and future prospects of this innovative way of using lactic acid bacteria are also discussed

Dynamic Modeling of <i>Carnobacterium maltaromaticum</i> CNCM I-3298 Growth and Metabolite Production and Model-Based Process Optimization

Carnobacterium maltaromaticum is a species of lactic acid bacteria found in dairy, meat, and fish, with technological properties useful in food biopreservation and flavor development. In more recent years, it has also proven to be a key element of biological time–temperature integrators for tracking temperature variations experienced by perishable foods along the cold-chain. A dynamic model for the growth of C. maltaromaticum CNCM I-3298 and production of four metabolites (formic acid, acetic acid, lactic acid, and ethanol) from trehalose in batch culture was developed using the reaction scheme formalism. The dependence of the specific growth and production rates as well as the product inhibition parameters on the operating conditions were described by the response surface method. The parameters of the model were calibrated from eight experiments, covering a broad spectrum of culture conditions (temperatures between 20 and 37 °C; pH between 6.0 and 9.5). The model was validated against another set of eight independent experiments performed under different conditions selected in the same range. The model correctly predicted the growth kinetics of C. maltaromaticum CNCM I-3298 as well as the dynamics of the carbon source conversion, with a mean relative error of 10% for biomass and 14% for trehalose and the metabolites. The paper illustrates that the proposed model is a valuable tool for optimizing the culture of C. maltaromaticum CNCM I-3298 by determining operating conditions that favor the production of biomass or selected metabolites. Model-based optimization may thus reduce the number of experiments and substantially speed up the process development, with potential applications in food technology for producing starters and improving the yield and productivity of the fermentation of sugars into metabolites of industrial interest