Search results for "bacteriocin"

Incorporation of nisin in poly (ethylene-co-vinyl acetate) films by melt processing: a study on the antimicrobial properties

2011

Both industry and academia have shown a growing interest in materials with antimicrobial properties suitable for food packaging applications. In this study, we prepared and characterized thin films of ethylene-co-vinyl acetate (EVA) copolymer with antimicrobial properties. The films were prepared with a film blowing process by incorporating a nisin preparation as an antimicrobial agent in the melt. Two grades of EVA containing 14 and 28% (wt/wt) vinyl acetate (EVA 14 and EVA 28, respectively) and two commercial formulations of nisin with different nominal activities were used. The effect of the nisin concentration also was evaluated. The films with the highest antimicrobial activity were th…

Microbial characterisation of fermented meat productions from the Sicilian breed "Suino Nero dei Nebrodi"

2012

Two traditional sausage products (“salsiccia” and “salame”) processed from the raw meat of the Black Sicilian swine “Suino Nero dei Nebrodi” were microbiologically investigated during the manufacturing and ripening stages. Both products were dominated by lactic acid bacteria (LAB), especially rod-shaped types. The concentration of enterococci was consistent in salame. Coagulase-negative cocci increased slower than LAB. Yeasts showed an increasing trend during the ripening of both products. Enterobacteriaceae were counted at a constant level of about 105 CFU/g in both products, while pseudomonads diminished during ripening. Coagulase-positive staphylococci, Listeria monocytogenes and Salmone…

BATTERI LATTICI CON ATTIVITA’ ANTIBATTERICA ISOLATI DA FORMAGGI TRADIZIONALI SICILIANI

2013

The study was conducted on typical Sicilian cheeses made from raw cow milk (Caciocavallo Palermitano) and sheep milk (Vastedda della valle del Belice PDO e Pecorino PDO). Genotypic identification of the LAB isolates was carried out by 16S/23S rRNA sequencing. a total of 400 bacteria strains were isolated and genotypically identified as Lactobacillus spp., Lactoccoccus spp., Pediococcus spp., Leuconostoc spp., Enterococcus spp. and Streptococcus spp. Evaluation of bacteriocin-producing LAB was investigated in vitro using the “spot on the lawn” method (2) aganist Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis and Escherichia coli. Results showed a predominance of LAB sh…

A halocin acting on Na+/H+ exchanger of Haloarchaea as a new type of inhibitor in NHE of mammals

2006

10 páginas, 3 figuras.

The role of environmental factors and medium composition on bacteriocin-like inhibitory substances (BLIS) production by Enterococcus mundtii strains

2008

Bacteriocin-like inhibitory substances (BLIS)-producers Enterococcus mundtii WGWT1-1A, WGW11.2, WGJ20.1, WGJ40.2 and WGK53 from raw material origin were subjected to a study for the characterization of antimicrobial compound production under several growth conditions, including different cultivation media, growth temperatures, pHs, different concentrations and sources of nitrogen compounds, carbohydrates and other nutritional factors, and in the presence of different percentages of ethanol and NaCl. The five E. mundtii strains showed different behaviors. However, in all cases, MRS and sour dough bacteria (SDB) were found as the optimal media for BLIS production. In general, the higher BLIS …

Identification, typing, and investigation of the dairy characteristics of lactic acid bacteria isolated from 'Vastedda della valle del Belìce' cheese

2013

Traditional cheeses made without starter cultures can be characterised by the attribute of instability. The addition of autochthonous starter cultures can ensure stability without compromising the characteristics of the final product. This study aimed to characterise the autochthonous lactic acid bacteria (LAB) population in “Vastedda della valle del Belice” cheeses, which have a protected designation of origin (PDO) status, in order to develop an ad hoc starter culture to be used in its future production. Winter and spring productions were analysed to ensure isolation of specific LAB that had adapted to perform fermentation at low temperatures. Plate counts revealed total microbial numbers…

Microbial strategies to improve the final quality of traditional Sicilian cheeses

An investigation of the bacteriocinogenic potential of lactic acid bacteria associated with wheat (triticum durum) kernels and non-conventional flours

2008

One hundred and thirty-seven lactic acid bacteria (LAB), previously isolated from wheat (Triticum durum) grains and non-conventional flour samples, were tested for the production of antibacterial substances. A total of 16 strains (5 Enterococcus faecium, 5 Enterococcus mundtii, 4 Pediococcus pentosaceus, 1 Lactobacillus coryniformis and 1 Lactococcus garvieae) were found to inhibit the growth of Listeria innocua. The antibacterial activities were preliminarily investigated for their general behaviour with proteolytic (proteinase K, protease B and trypsin), amylolytic (α-amylase) and lipolytic (lipase) enzymes, after heat treatment, and exposure to different pHs and ethanol concentrations. B…

Characterization of Lactobacillus isolates from fermented olives and their bacteriocin gene profiles

2011

Near one hundred isolates of Lactobacillus paraplantarum, Lactobacillus pentosus and Lactobacillus plantarum from table olives were studied. Strains were genotyped by rep-PCR. Although the technique failed to differentiate some isolates at the species level, it proved a robust and easy procedure that could be useful for distinguishing between related strains of L. paraplantarum, L. pentosus and L. plantarum from a large pool of unrelated strains of these species. A PCR-based screening revealed the presence of the plantaricin encoding genes plnA, plnB, plnC, plnD, plnE/F, plnF, plnI, plnJ, plnK, plnG and plnN in most isolates of the three species. Sequences of bacteriocin genes present in L.…

Antibacterial polypeptides of Lactobacillus species

1990

Twelve of 79 strains of the genus Lactobacillus, mainly isolated from plants or fermenting material, were found to inhibit at least one of the nine indicator strains of the species Lact. brevis, Pediococcus damnosus and Leucanostoc oenos. The antimicrobial activities from Lact. brevis B 37 and Lact. casei B 80 were caused by polypeptides detectable in the culture liquids. They are bacteriocins with a narrow antimicrobial spectrum. Brevicin 37 from Lact. brevis B 37 was active against many lactic acid bacteria and Nocardia corallina, whereas caseicin 80 from Lact. casei B 80 inhibits only one other strain of Lact. casei. Brevicin 37 is stable at 121dC, caseicin 80 is inactivated above 60dC, …