Abstract

Lactobacillus plantarum and Pediococcus pentosaceus strains isolated from dairy milk products, produced bacteriocins that displayed a wide spectrum of antimicrobial activity against Listeria ivanovii and food spoilage microorganisms. The two bacteriocins were thermally stable over a wide temperature range up to 100°C for 15 min and retained their activity at pH 2.0 to 6.0. Full bacteriocins activity were stable after three months of storage at 4 and -20°C, for 75 min of exposure to UV light, bacteriocin produced by P.pentosaceus was completely destroyed, but the second L. plantarum remained stable after the same time of exposure; treatment with proteolytic enzymes resulted in a remarkable stability of activity. Results obtained showed an increase in bacteriocins activity of the both strains against L. ivanovii on increasing the concentration of NaCl and KCl up to 5%, in presence of spices 5%, stability to acetone and hexane indicated that both surfaces were rather hydrophilic and bipolar. Further studies are required regarding suitable bioprocessing strategies for an efficient bacteriocin production process.

Key words: Lactobacillus plantarum, Pediococcus pentosaceus, bacteriocin activity, temperature, pH, enzymes, solvents, salts, spices.