Andrade, Mário

Campos, Francisco

Couto, José António

Hogg, Tim

Pereira, Marcos T.

Redondo, Luís

Santos, João

English

Repositório Institucional da Universidade Católica Portuguesa

 1                   PORTUGUESE CONGRESS OF  MICROBIOLOGY AND BIOTECHNOLOGY Micro Biotec‘13 6th – 8th December | Aveiro Portugal Abstracts Book  98   Food Microbiology & Biotechnology P067  THE ANTIMICROBIAL EFFECT OF PULSED ELECTRIC FIELDS (PEF) AGAINST BRETTANOMYCES/DEKKERA YEASTS  José António Couto1; João Santos2; Luís Redondo3; Mário Andrade4; Francisco Campos1; Tim Hogg1; Marcos T. Pereira2  1 CBQF/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal (*e-mail: jcouto@porto.ucp.pt) 2 Energy Pulse Systems, Estrada do Paço do Lumiar, Polo Tecnológico de Lisboa, Lote 3, 1600-546 Lisboa – Carnide, Portugal 3 Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emídio Navarro 1, 1959-007 Lisboa, Portugal 4Caldeira Andrade Lda, Av. António dos Santos 1, 4ºF, 2000-074 Santarém, Portugal  PEF is known to provoke a dramatic increase in cell membrane permeability caused by externally applied short and intense electric pulses (1). One possible application of PEF is on the microbiological control of food by the inactivation of pathogenic and spoilage organisms in food matrixes including liquids (2). Puertolas et al (3) applied this technology on several wine spoilage microorganisms. Brettanomyces / Dekkera are well known to be involved in the production of volatile phenols in wines imparting aroma defects that may affect wine quality (4). The monitoring and control of these organisms is of major importance for wine producers.This work aimed to evaluate the effect of PEF on the survival of Brettanomyces / Dekkera in a continuous system, taking into account the energy efficient needed for industrial scale.Cell suspensions prepared by diluting YM culture medium with sterile water (1:10) were submitted to the following PEF parameters: electric field 10 kV/cm, pulse width 50 µs, pulse frequency 50 Hz, pulse current 13 A, using a EPULSUS-PM1-10@ modulator. A cell inactivation effect was observed leading to a reduction of 3 logarithmic cycles of the initial population in 2 min for both strains tested (Dekkera bruxellensis PYCC 4801 and Dekkera/Brettanomyces 2). When only distilled water was used as cell suspension medium exposed to 100 µs, 100 Hz and 3 A of pulse width, frequency and current respectively, for 5 min, cell survival was almost unaffected. The electroporation medium composition and the way it influences properties such as medium conductivity seems to play an important role on the efficiency of the method. This is a preliminary study approaching for the first time the application of a continuous PEF system to wine spoilage organisms. Future work will focus on the influence of PEF parameters, medium composition and strain variability on PEF efficiency, along with the minimum energy needed for the microbial inactivation.  (1) Kanduser, M. and Miklavcic, D.2008. Electrotechnologies for Extraction from Food Plants and Biomaterial. E. Vorobiev, N. Lebovka (eds.), Springer Science+Business Media, LLC (2) Barbosa-Cánovas, G.V., Fernández-Molina, J.J., Swanson, B.G., 2001. Pulsed electric fields: A novel technology for food preservation. Agro Food Industry Hi-Tech 12: 9–14. (3) Puértolas, E., López, N., Condón, S., Raso, J. and Álvarez, I. 2009. Pulsed electric fields inactivation of wine spoilage yeast and bacteria. Int J Food Microbiol. 130: 49–55. (4) Chatonnet, P., Dubourdieu, D. and Boidron, J.N., 1995. The influence of Brettanomyces/Dekkera sp. and lactic acid bacteria on the ethylphenol content of red wines. Am J Enol Viticult 46 (4): 463-467   

The antimicrobial effect of pulsed electric fields (pef) against brettanomyces/dekkera yeasts

https://repositorio.ucp.pt/bitstream/10400.14/14345/1/The%20antimicrobial%20effect%20of%20pulsed%20electric%20fields%20%28pef%29%20against%20brettanomyces-dekkera%20yeasts.PDF

The antimicrobial effect of pulsed electric fields (pef) against brettanomyces/dekkera yeasts

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Repositório Institucional da Universidade Católica Portuguesa