Survie des bactéries lactiques soumises à la déshydratation : importance de la cinétique de déshydratation

Abstract

Abstract-Viability of lactic bacteria submitted to dehydration: Importance of the dehydration kinetics. Dehydration of Lactobacillus plantarum by glycerol addition (water depressor) has allowed to show the great importance of the kinetics of water potential decrease on cell viability. Thus, wathever the final water potential was, an optimal kinetics of water potential variation was detennined which allow to maintain a viability higher than 80%. Decreasing rate and level of water potential have been proved to influence cell viability in the same way during air drying at 25 oc. In this case, optimal kinetics of dehydration preserved 40% of viable cells. This viabilit Y was higher than 80% when a nutritional stress was realised before dehydration and when cells were rehydrated at 37 oc. A high preservation of dehydrated cells was observed for 3 months at -317.9 MPa (~= 0.100); and after rehydration, stressed cells exhibited an acid production similar to a control. © Inra/Elsevier, Paris. Lactobacillus plantarum