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

Research Note

Quality of silages from Italian farms as attested by number and identity of microbial indicators.

AIMS: This study evaluated the quality and possible hygiene risks related to farm-made silages by analysing the presence and number of micro-organisms that influence the preservation and safety in samples from four Italian regions. METHODS AND RESULTS: Lactic acid bacteria, clostridia, lactate-fermenting yeasts and propionibacteria (PAB) were isolated and identified by random amplified polymorphic DNA PCR, sequencing of the V2-V3 16S rRNA gene region, 5.8S-ITS rDNA RFLP and species-specific PCR. The Lactobacillus plantarum cluster was the most numerous and comprised strains mostly isolated from alfalfa silage. The Lactobacillus buchneri cluster, second in number, comprised isolates from both alfalfa and maize silage. Anaerobic spore formers were assigned to the species Clostridium baratii, Clostridium beijerinkii, Clostridium butyricum, Clostridium perfringens, Clostridium saccharolyticum, Clostridium tyrobutyricum and Paenibacillus macerans. Yeast isolates were identified as Candida apicola, Candida mesenterica and Pichia fermentans. PAB strains, detected only in unifeed, were all identified as Propionibacterium acidipropionici. CONCLUSIONS: The occurrence of spoiling micro-organisms was frequent and the possibility of contamination by potentially pathogenic clostridia was demonstrated. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest the need for improved ensiling practices and appropriate control measures to safeguard the hygienic and nutritional quality of silages produced in farms

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