61C-18 |
Production and partial characterization of a bacteriocin produced by Pediococcus parvulus |
J. C. HERNÁNDEZ-LÓPEZ1, F. J. Fernández-Perrino, I. Guerrero-Legarreta, and E. PONCE-ALQUICIRA4. (1) Biotecnología, Universidad Autónoma Metropolitana, Av. San Rafael Atlixco No.186 Col. Vicentina, Mexico, D.F., 09340, Mexico, (2) Bioquimica de Macromoleculas, Mexico Lactic acid bacteria (LAB) produce various antimicrobial substances; among them, bacteriocins have generated a great interest as natural preservatives in foods. In general LAB have complex growth requirements that in conjunction with the environmental growing parameters may influence the bacteriocin production. Additionally, it is necessary to evaluate the efficiency of bacteriocins as biopreservatives by determining their spectrum of activity, production conditions and stability to various environmental conditions. The objective of this work was to assess the potential use of the bacteriocin produced by Pediococcus parvulus VKM133 as a biopreservative in foods. Pediococcus parvulus was isolated from fresh sausages and identification was based on 16S rRNA gene sequence similarity. The bacteriocin was produced in MRS broth in microaerobic and anaerobic conditions at various temperatures from 20 to 45°C. Antimicrobial activity was assayed using the agar diffusion technique against several LAB strains, Enterococcus faecium and Listeria innocua. Proteinase sensibility, stability to pasteurization and sterilization processes; and shelf life at room temperature (25°C), refrigeration (4°C) and freezing (–20°C) were also evaluated. Results showed that the bacteriocin inhibited the growth of strains from the genus Lactobacillus, Lactococcus, Enterococus and Listeria. The highest activity was obtained when the strain was cultivated at 40°C under microaerobic conditions. The bacteriocin was sensitive to trypsine and proteinase K and stable when subjected to pasteurization. The bacteriocin activity was gradually lost in relation with the temperature of storage. The activity was lost during the first 10 days of storage at 25°C. However, 60 and 100% of the original activity was retained after 4 months of storage at 4°C and –20°C, respectively. Therefore, this bacteriocin could be applied as a biopreservative in pasteurized foods stored under refrigeration or freezing temperatures, inhibiting the growth of a wide range of microorganisms.
Session 61C, Food Microbiology: General I
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