Premium
Evaluation of Antimicrobial Activity and Safety Aspect of E nterococcus Italicus GGN 10 Strain Isolated from T unisian Bovine Raw Milk
Author(s) -
Gaaloul Necima,
Ben Braiek Olfa,
Berjeaud Jean Marc,
Arthur TIMOTHY,
Cavera Veronica L.,
Chikindas Michael L.,
Hani Khaled,
Ghrairi Taoufik
Publication year - 2014
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/jfs.12126
Subject(s) - bacteriocin , antimicrobial , lactic acid , bacteria , fermentation , microbiology and biotechnology , proteolytic enzymes , enzyme , biology , chemistry , food science , biochemistry , genetics
Screening of lactic acid bacteria ( LAB ) from T unisian raw bovine milk has resulted in the isolation of an E nterococcus italicus strain designated as GGN 10, which has demonstrated a bacteriocin‐like activity against L isteria spp. Antibacterial activity in the culture supernatant was lost after treatment with proteolytic enzymes, whereas it was stable over a wide range of pH (2–10). The treatment of extracellular extract of this strain at 100 C did not cause loss of antimicrobial activity. The bacteriocin yield reached a maximum of 67,677.1 AU /mL at the beginning of the exponential growth phase and remained stable during 24 h of incubation. Amplification of bacteriocin genes revealed ent A and ent B genes present in GGN 10. In addition, this result was confirmed by the bacteriocin's reversed‐phase high‐performance liquid chromatography purification and mass spectrometry analysis. This is the first report on enterocins A and B production by this newly isolated strain. Safety elucidation and antibiotics susceptibility of E . italicus GGN 10 was conducted using polymerase chain reaction analysis. No commonly associated pathogenicity islands were identified. An enzymatic study revealed GGN 10 as a high producer of acid phosphatase and aminopeptidase, which are important features in flavor and texture development during fermentation. Thus, E . italicus GGN 10 produces antimicrobial substances and other biologically active substances of importance for food preservation. Practical Applications The potential advantages of discovering new lactic acid bacteria strains offer new possibilities in terms of food application, which may have potent socioeconomic applications. Studies on the local microflora in raw milk contribute to the understanding of both the environment and how selected wild strains can be used with fermented foods. In this study, the strain E nterococcus italicus GGN 10 isolated from raw milk was identified as a means of providing a powerful tool for inhibiting pathogenic organisms such as L isteria monocytogenes in dairy foods.