Journal of Food Processing & Technology

Influence of pH on the growth of an autochthonous lactic acid bacteria and bacteriocin production with antilisterial activity

21^st Euro-Global Summit on Food and Beverages

March 08-10, 2018 | Berlin, Germany

Ariana Macieira, Joana Barbosa, Helena Albano, Alcina M M B Morais and Paula Teixeira

CBQF - Universidade Católica Portuguesa, Portugal

Scientific Tracks Abstracts: J Food Process Technol

Abstract:

Introduction: Listeria monocytogenes is a great concern in the food industry. Bacteriocins, produced by Lactic Acid Bacteria (LAB) are of great importance in order to face this concern. The reason for that is because some bacteriocins have demonstrated antimicrobial activity against L. monocytogenes and do not alter the organoleptic characteristics of the products. MRS broth can fulfil fastidious growth requirements of most LAB, so it is used for the growth of Lactic Acid Bacteria and for bacteriocin production. It is known that pH can have some effects over the production of bacteriocins. So, the objective of this study was to investigate how the pH value could influence the growth of an autochthonous strain of Lactobacillus and the production of bacteriocin active against L. monocytogenes. Methodology: From previous studies with different LAB, isolated from traditional meat products, an autochthonous Lactobacillus strain was selected since it demonstrated antimicrobial activity against L. monocytogenes and do not alter the organoleptic characteristics of the tested products. Bacteriocins were tested against five strains of Listeria monocytogenes. The selected Lactobacillus strain was grown in MRS broth for 21 h at 37°C in a batch reactor. Two different batchs were prepared. In one pH was controlled over time (pH=6.5) and in the other one LAB growth and bacteriocin production were performed under uncontrolled pH. Results & Conclusions: Higher bacteriocin activity was observed when LAB were grown under controlled pH. Maximum antimicrobial activity was about 12800 Au/mL for every Listeria monocytogenes tested, after 18 hours of LAB growth when the pH of the medium was controlled. This antimicrobial activity could be maintained, even after 20 hours of LAB growth. Recent publications 1. Bhugaloo Vial, P Grajek, W Dousset, X Boyaval P (1997) Continuous bacteriocin production with high cell density bioreactors. Enzyme and Microbial Technology 21:450â??457. 2. Bogovic-Matijasic B, Rogeli I (1998) Bacteriocin complex of Lactobacillus acidophilus LF221 â?? production studies in MRS-media at different pH-values and effect against Lactobacillus helveticus ATCC 15009. Process Biochem. 33: 345â?? 352. 3. Daeschel M A, Mckeney M C, McDonald L C (1990) Bacteriocidal activity of Lactobacillus plantarum C-11. Food Microbiol. 7: 91â??98. 4. Pleasants A B, Soboleva T K, Dykes G A, Jones R J, Filippov A E (2001) Modelling of the growth of populations of Listeria monocytogenes and a bacteriocin-producing strain of Lactobacillus in pure and mixed cultures. Food Microbiology. 18: 605-615. 5. Vignolo G, Palacios F, Farías M E, Sesma F, Schillinger U, Holzapeel W, et al. (2000) Combined effect of bacteriocins on the survival of various Listeria species in broth and meat system. Current Microbiology 41: 410- 416.

Biography :

Ariana Macieira is a researcher working in Paula Teixeira’s group in Universidade Católica Portuguesa, in Porto, Portugal. She has been doing some work in the field of bacteriocins production by trying to find some techniques that will improve LAB bacteriocins with application in the food industry.
Email:arianamacieira@gmail.com