Competitiveness of the bacteriocinogenic strain Enterococcus mundtii CRL35 for meat fermentation

VILDOZA MJ; SAAVEDRA L; SESMA, F; 1.VIGNOLO G; FADDA S

Estambul

Congreso; 23rd ICFMH Food Micro; 2012

ICFMH Food Micro

Enterococcus species, a group of lactic acid bacteria (LAB), are ubiquitousmicroorganisms which constitute a large proportion of the autochthonous microbiotafound in artisanal fermented foods. Enterococcus mundtii CRL35, isolated from artisanalArgentinean cheese, was reported as a bioprotector culture (BC) because of its listeriaactivebacteriocin production (enterocin CRL35). Considering that this species has alsobeen detected as part of the natural microbiota of Argentinean regional sausages; the aimof this work was to evaluate the competitiveness of E. mundtii CRL35 during the meatfermentation process. In vitro analyses were carried out in a sterile meat fermentationmodel (MFM) with and without curing additives (CA) (100 ppm NO2, 70 ppm ascorbicacid, 3% NaCl, 0.75% glucose, 0.75% sucrose). E. mundtii CRL 35 showed optimalgrowth and acidification in MFM with a maximal bacterial growth at 24 h with curingagents (8.6 Log CFU /ml; pH=4.3) and without CA (8.8 log CFU/ml; pH=4.4).Interestingly, a higher bacteriocin production (9.6 X103 UA/ml) at 24 h, was observed inthe presence of CA. In order to understand the effect of CA in bacteriocin activity,Food Micro 2012 - www.verus.com.tr http://www.onlinebildiri.com/foodexpression of munA and mun B genes, enconding for the bacteriocin peptide and theABC-transporter, respectively; under the presence and absence of the curing mixturewere analyzed by Real Time PCR. These results demonstrated that the expression ofbacteriocin genes was not affected by CA addition. On the other hand, Listeria time-killcurves using synthetic enterocin CRL35 showed that CA improves the antimicrobialactivity of this peptide. These results suggest that the stimulatory effect of CA might bedue to interactions between these compounds and the protein itself. Besides, E. mundtiiCRL35 was able to hydrolyze sarcoplasmic proteins as another important technologicalfeature. In summary, E. mundtii CRL35 may find a practical application as a novelfunctional starter culture for sausage fermentation ensuring hygienic and sensorial qualityin the final product.Enterococcus mundtii