Growth Kinetics and Bacteriocin Production by Three Enterococcus Strains under Low-temperature Stress

AIM: The production of bacteriocins under temperatures close to those that can be found during conservation of milk products had to be investigated in order to retrieve maximal advantage of these naturally occurring anti-spoilage agents. METHODS: Cultivations of the BLIS producer strains were performed at 8 oC, and the cell number and the BLIS activities were determined at regular intervals. The growth parameters were analyzed by modeling with appropriate software. RESULTS: 1) low temperatures significantly reduce the BLIS activity of two of the strains, Enterococcus faecium 3587 and Enterococcus faecalis 3915, while in the third strain, Enterococcus durans M-3, it was stimulated; 2) For all strains bacteriocin activity was higher when cultivation was performed on MRS broth rather than on M-17, and 3) the three strains showed the typical growth for Enterococci in conditions of low temperature cultivation. CONCLUSIONS: Temperature stress can up-regulate or down-regulate the BLIS synthesis depending on the strain.