Viability kinetics of Lactobacillus casei Shirota strain in a commercial fermented milk drink during refrigerated storage

Abstract

Background: One of the most important parameters in a commercial fermented milk drink containing probiotics is the viability of the microorganisms. Aims and Objectives: This study described the viability kinetics of Lactobacillus casei Shirota strain in a commercial fermented milk drink during refrigerated storage using nonlinear models. Materials and Methods: Viability of L. casei Shirota strain was monitored during refrigerated storage using standard bacterial plate count method. Several nonlinear mathematical models such as the zero-order, first-order, and second-order kinetic equations were employed in describing the population dynamics. Best-fit models were selected based on prescribed criteria including sum of squares of the error, p-value, and coefficient of determination. Results: The viable counts of L. casei Shirota strain in the fermented milk samples stored under refrigerated conditions decreased from 3.73 × 10 8 colony forming units per ml (CFU/ml) to 2.70 × 10 8 CFU/ml when monitored every 3-4 days interval over 10 different monitoring points within the product's indicated shelf life. The counts significantly differed between the monitoring points that were at least 14 days apart. The lowest viable count was still within the recommended therapeutic dose. The decrease in the bacterial population behaved under a second-order kinetic relationship. Conclusion: The viability of L. casei Shirota strain in a commercial fermented milk product during refrigerated storage is governed in accordance with the second-order kinetic mechanism.

Varying concentrations of sucralose and the acid-producing capability of Lactobacillus acidophilus

“…[31] However, the viability of Lactobacillus casei decreased in a fermented milk drink during refrigerated storage. [32] In the present study, there was a decrease in the change in pH as the concentration of SPLENDA® was increased. This decrease in pH was associated with the increase in the number of L. acidophilus bacteria.…”

Survival of Lactobacillus casei and functional characteristics of reduced sugar red beetroot yoghurt with natural sugar substitutes

“…The growth of L. casei is affected by such fermentation parameters, as pH, temperature and food matrix/design (Sumalapao et al . 2017). Regarding the growth proportion index (GPI) of L. casei , the rate of development was similar in all samples at the end of fermentation and during the storage (Figure 1).…”

Probiotic viability, pH and lactic acid concentration of opened commercial probiotic dairy drinks stored at different temperatures and durations

“…The viability of probiotics during storage is strain or species-dependent, and it is also influenced by the manufacturing process or composition of probiotic products. Most of the studies showed that the survival of probiotics could be steadily maintained in the commercial products over the storage duration, although some probiotics might slightly lose their viability (Shah et al 2000;Al-Otaibi 2009;Liu 2011;Dharmasena 2012;Haddad 2017;Sumalapao et al 2017). However, the viability of the opened commercial cultured probiotic milk and their physicochemical properties, especially pH and D-lactic acid, are yet to be examined after being opened and stored for a few days.…”