Resumo

Enterococci are widespread in various raw food systems especially from animal source. The potential health attributes of this gender includes the control of gastrointestinal infections, reduction of serum cholesterol and also current studies have shown that various strains of lactic acid bacteria (LAB) exhibit antioxidative and antimicrobial activity. So, the aim of this study was to evaluate the antimicrobial and the antioxidant properties of LAB18s isolated from “Minas Frescal” cheese and identified as Enterocuccus durans. The antimicrobial activity of LAB18s was tested with two extract (culture supernatant and intracellular extract) against different indicator pathogenic microorganisms: Listeria monocytogenes, Escherichia coli, Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium, S. Enteritidis, Pseudomonas aeruginosa, Aeromonas hydrophila and Corynebacterium fimi. The reaction to thiobarbituric acid (TBARS) was performed with the previously oxidation of extra virgin olive oil with ferrous sulfate. Thereafter, it was added the samples, sodium dodecyl sulfate, buffered with acetic acid and thiobarbituric acid. The concentration of TBARS was calculated using a standard curve (1,1,3,3-tetramethoxypropane). The antioxidant activity was determined using ABTS•+ (2,2 azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radical cation method. Ascorbic acid was used as the standard in the range 0–9 μg mL-1. The scavenging ability on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals was also performed. The standard curve was DPPH in the range between 0 to 60 μM. The results from antimicrobial activity showed that the LAB18s exhibited a high inhibition zone for all indicator microorganisms tested, except to B. cereus, S. aureus and S. Enteritidis when used the culture supernatant, and to S. Typhimurium when used the intracellular extract. It was analyzed the antioxidant activity for culture supernatant and intracellular extract of LAB18s by ABTS•+ and DPPH methods, and it was observed that only culture supernatant presented ability to scavenge for both methods. However, when it was analyzed the sample by TBARS method, it was observed high antioxidant activity with both extracts. In conclusion, the antimicrobial and antioxidant capacities of LAB18s indicate that it could be very useful in food fermentation and feed composition. It could particularly help to inhibit pathogenic microorganisms as well as oxidative spoilage in foods and feeds.