Competitiveness of the bacteriocinogenic strain Enterococcus mundtii CRL35 for meat fermentation

VILDOZA MJ; SAAVEDRA L; SESMA F; VIGNOLO G; FADDA S

Estambul

Simposio; 23rd International ICFMH Symposium; 2012

ICFMH

Enterococcus species, a group of lactic acid bacteria (LAB), are ubiquitous microorganisms constitute a large proportion of the autochthonous microbiota found in artisanal fermented foods. Enterococcus mundtii CRL35, isolated from artisanal Argentinean cheese,reported as a bioprotector culture (BC) because of its listeria-active bacteriocinproduction (enterocin CRL35). Considering that this species has also been detected as part of natural microbiota of Argentinean regional sausages; the aim of this work was to evaluate the competitiveness of E. mundtii CRL35 during the meat fermentation process. In vitroanalysis were carried out in a sterile meat fermentation model (MFM) with and withoutcuring additives (CA) (100 ppm NO2, 70 ppm ascorbic acid, 3oA NaCl, 0.75% glucose and sacarose. E. mundtii CRL 35 showed optimal growth and acidification in MFM with a maximal bacterial growth at 24 h with curing agents (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 xl03 at 24 h, was observed in the presence of CA. In order to understand the effect of CAon bacteriocin activity, expression of munA and mun B genes, enconding for the bacteriocinand the ABC-transporter, respectively; under the presence and absence of the curing additives were analyzed by Real Time PCR. These results demonstrated that the expression of bacteriocin genes was not affected by CA addition. On the other hand, Listeria time-killcurves using synthetic enterocin CRL35 showed that CA improves the antimicrobial activityof this peptide. These results suggest that the stimulatory effect of CA might be due tointeractions between these compounds and the protein itself. Besides, E. mundtii CRL35 was able to hydrolyze sarcoplasmic proteins as another important technological feature. Insummary, E mundtii CRL35 may find a practical application as a novel functional starterculture for sausage fcrmentation ensuring hygienic and sensorial quality in the final product.