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Spore mods 2019
Spore mods 2019






spore mods 2019

In contrast, vegetative cells are more sensitive to stress, are physiologically active, and can produce degradative enzymes or toxins, form biofilms, and differentiate into resistant spores. The spores are metabolically inactive, but they are commonly resistant to physical and chemical treatments applied in the food industry. The sporeformers display many physiological and enzymatic capacities. Bacterial cells in their vegetative or sporulated forms can be found in the environment and therefore can be natural contaminants of raw materials.

spore mods 2019

Spore-forming bacteria are common contaminants of food, and represent a major source of food poisoning and food spoilage ( 1, 2). Further, this model can be used to assess these data under various environmental conditions in order to better identify the conditions favorable for sporulation regarding the time to obtain the first spore and/or the concentrations of spores which could be reached during a food process.

spore mods 2019

Consequently, the model constitutes an interesting tool to assess the sporulation potential of a bacterial population over time with accurate parameters such as the time needed to obtain one resistant spore and the probability of sporulation. IMPORTANCE The growth-sporulation model describes the progressive transition from vegetative cells to spores with sporulation parameters describing the sporulation potential of each vegetative cell. This model provides physiological information on the spore formation and on the temporal abilities of vegetative cells to differentiate into spores and reveals the heterogeneity of spore formation during and after growth. The biological meaning of the parameters was validated with a derivative strain of Bacillus subtilis 168 which produces green fluorescent protein at the initiation of sporulation. The model accurately describes the kinetics in these different conditions, with a mean error lower than 0.78 log 10 CFU/ml for the growth and 1.08 log 10 CFU/ml for the sporulation. The goodness of fit of this growth-sporulation model was assessed using growth-sporulation kinetics at various temperatures in laboratory medium or in whey for Bacillus subtilis, Bacillus cereus, and Bacillus licheniformis. Two parameters are related to the probability of each vegetative cell to commit to sporulation and to form a spore, and the last one is related to the time needed to form a spore once the cell is committed to sporulation. The model is based on a classical growth model and enables description of the kinetics of sporulation with the addition of three parameters specific to sporulation. In order to characterize and to predict spore formation over time, we developed a model that describes both the kinetics of growth and the differentiation of vegetative cells into spores. Spore-forming bacteria are natural contaminants of food raw materials, and sporulation can occur in many environments from farm to fork.








Spore mods 2019