Interactions between Saccharomyces and Oenococcus oeni strains from Amarone wine affect malolactic fermentation and wine composition

Research Note

Microbiological variations in silage of lucerne and italian rye-grass with added lactic acid bacteria or formic acid

In this study the quantitative and qualitative variations of useful and harmuf microflora were followed during ensilage of Italian rye-grass and lucerne. In addition the effects of adding lactic acid bacteria or formic acid to these foffers was studied. After only four days of ensilage the LAB addition determined a faster lowering of pH. In particular, moulds were actively inhibited

DNA-DNA homology, physiological characteristics and distribution of lactic acid bacteria isolated from maize silage

Lactic acid bacteria represent a dynamic bacterial group in maize silage. Their establishement, variations and characterization have been studied by investigating 22 samples taken at different times during the ensilage process. After a preliminary screening based on physiological characteristics 100 of 229 strains isolates were chosen for further taxonomic investigation. Twenty-nine strains of Homofermentative lactobacilli were identified as L. plantarum, L. casei and L. coryniformis; 24 heterofermentative strains were allotted to L. buchneri, L. brevis, L. fermentum and Lc paramesenteroides; 22 coccal strains as E. faecium, S. lactis and S. bosis. A few strains remained unidentified

Production of DL lactic acid by an atypic strain of Lactobacillus bulgaricus

Attempts to increase the L(+) lactic acid content in fermented foods are in progress in several countries. We refer to an alypical strain of Lactobacillus bulgaricus able to produce DL lactic acid instead of D(-) isomer. A possible correlation between presence of plasmid anf L(+) lactic acid production is suggested

Tracing Pediococcus acidilactici in ensiled maize by plasmid-encoded erythromycin resistance

Curing experiments undertaken on Pediococcus acidilactici strain S364, isolated from maize silage, revealed a linkage between a resident 40 MD plasmid and resistance to erythromycin, oleandomycin and tylosin. The possibility of using erythromycin resistance to monitor the fate of this strain in a model ensiling system was also demonstrated

Microbiological contribution to the study of Monte Veronese Cheese

The aim of this research was to investigate the starter and non starter lactic acid bacteria of long ripened Monte Veronese cheese (a traditional raw cows' milk cheese from the North East of Italy). A total of 315 isolates, obtained form samples collected at various stages during manufacture and ripening of Monte VEronese cheese, were identified and characterized using physiological and genetical methods. RAPD-PCR proved to be a fast and reliable tool for identification of strains and revealed the existence of intraspecific genetic variability. Moreover, a clear differentiation of isolates on the basis of their technological characteristics was recognized. The data obtained in this study can be exploited for the development of specific indigenous starter cultures for use in the manufacture of traditional long ripened Monte Veronese cheese

Diffusione di enterococchi vancomicina-resistenti in prodotti carnei

In this research some potential sources of vancomycin-resistant enterococci (VRE) were analysed. A total of 43 strains were isolated from samples of raw and processed meat products. VRE could be detected after an enrichment in TSYE supplemented with vancomycin in 75% of samples which contained enterococci. Most strains belonged to Enterococcus faecium species, as determined by traditional physiological tests, and by SARA-PCR and species-specific PCR assays, and the remaining to E. faecalis and E. durans species. All the VRE isolates, identified as E. faecium (17 strains) and E. faecalis (3 strains), were highly resistant to vancomycin and teicoplanin (>64 \u3bcg/mL) and harboured the vanA gene, as shown by PCR

Taxonomy of probiotic microorganisms

When referring to probiotics we refer to probiotic strains, i.e. the microbial individuals, sub-cultures of billion of almost identical cells ideally derived from the same mother cell. Therefore, beneficial effects attributed to probiotics are ascribed in fact to specific strains. However, these strains have to be, by law, clearly identified at the species level. In fact, probiotics have to be safe for consumption, and the evaluation of QPS \u2013 Qualified Presumption of Safety \u2013 status by the European Food Safety Authority (EFSA) is discussed for species, not for single strains. Also, corrected names have to be reported on products labels: failure of identification of the declared species is a commercial fraud and a consumer misleading, besides being an indication of unreliability of the product. These two examples should clarify how important is the correct taxonomic identification of probiotic strains in the assessment of their reliability and efficacy. The aim of the present contribution is to clarify which procedures, rules and scientific knowledge stand behind microbial names, as results of taxonomic analysis. Probiotic strains described to date fall in two different groups of microorganisms, namely bacteria and yeasts, which will be the focus of this treatment