Physiological characterization of probiotic strains for applications in food industry

Potential probiotic strains from different origins have been tested for some specific physiological properties in order to evaluate their application potentialities. The phenotypic characterisation of examined lactic acid bacteria have done using the API tests and BIOLOG system. All of tested strains survive lyophilization process in skim milk at high population level. Lyophilised strains remained viable at all examined temperatures during 75 days of storage. Recovery of viable cells during storage in the phosphate buffer with glycerol was about 100 % at – 20 oC for all strains. Cells of L. acidophilus M92 rapidly died during storage at 4 and 15 oC, while cells of L. plantarum L4 and E. faecium L3 survive at the number of ca. 104 cells/ml. The potential probiotic strains have shown antagonistic activity against all tested gram-positive and gram-negative spoilage and pathogenic bacteria using 3 different methods (agar-spot test, agar-well diffusion method and in vitro competition test). The inhibition obtained by neutralised 5-fold concentrated supernatant of L. plantarum L4 may be result of bacteriocin activity of this strain.