Study of the nutritional changes and evolution of microbiota during sourdough like fermentation of wheat bran

Several studies have emphasized the possibility to enhance nutritional properties of cereal by-products through biotechnological processes. Bran fermentation positively affects the bioavailability of several functional compounds and, in particular, it could increase water-extractable arabinoxylans (WEAX), compounds with positive effects on glucose metabolism and potential prebiotic properties. This study was aimed to increase the amount of bran\u2019s bioactive compounds through sourdough like fermentation process. Wheat bran fermentations were conducted through continuous propagation by back-slopping of fermented bran (10% inoculum) until a stable microbiota was established, reaching high counts of lactic acid bacteria and yeasts (109 and 107 CFU g-1 respectively). After fermentation, levels of soluble fiber increased (+ 30%), WEAX and free ferulic acid were respectively fourfold and tenfold higher than in raw bran, results probably related to microbial xylan-degrading activity, while phytic acid was completely degraded. At each refreshment step, bacterial strains were isolated, clustered, molecularly analysed by Randomly Amplified Polymorphic DNA and identified at the species level by 16S rRNA gene sequencing. Leuconostoc mesenteroides, Lactobacillus brevis, Lactobacillus curvatus, Lactobacillus sakei, Lactobacillus plantarum, Pediococcus pentosaceus and Pichia fermentans were dominating the stable sourdough ecosystem. These strains were characterized by their metabolic and enzymatic activities, such as xylan- and phytate-degrading activities. These preliminary data suggest that fermented bran could be considered as an interesting functional ingredient for nutritional enhancement. The characterization of the bacteria involved in sourdough like fermentation process represents the first step toward selecting starter cultures, according to their functional aspects, in order to conduct \u201ctailored\u201d bran fermentation process aimed at improving its functional and nutritional properties

Study of the chemical changes and evolution of microbiota during sourdoughlike fermentation of wheat bran

Several studies have emphasized the possibility of enhancing nutritional properties of cereal by-products through biotechnological processes. Bran fermentation positively affects the bioavailability of several functional compounds. Moreover, bran fermentation could increase water-extractable arabinoxylans (WEAX), compounds with positive effects on glucose metabolism and prebiotic properties. This study was aimed at increasing the amount of bran bioactive compounds through a sourdoughlike fermentation process. Wheat bran fermentations were conducted through continuous propagation by back-slopping of fermented bran (10% inoculum) until a stable microbiota was established, reaching high counts of lactic acid bacteria and yeasts (109 and 107 CFU/g, respectively). At each refreshment step, bacterial strains were isolated, clustered, molecularly analyzed by randomly amplified polymorphic DNA, and identified at the species level by 16S rRNA gene sequencing. Leuconostoc mesenteroides, Lactobacillus brevis, Lactobacillus curvatus, Lactobacillus sakei, Lactobacillus plantarum, Pediococcus pentosaceus, and Pichia fermentans dominated the stable sourdough ecosystem. After fermentation, levels of soluble fiber increased (+30%), and WEAX and free ferulic acid were respectively fourfold and tenfold higher than in raw bran, results probably related to microbial xylan-degrading activity, whereas phytic acid was completely degraded. These preliminary data suggest that fermented bran could be considered an interesting functional ingredient for nutritional enhancement

Sand bedding as a reservoir for Lactococcus garvieae dissemination in dairy farms

Lactococcus garvieae is now recognized as a species with clinical significance for human and veterinary medicine. The aim of this study was to evaluate the presence of this pathogen in sand bedding and milk samples. Two farms in Minnesota with problems of clinical and subclinical mastitis due to streptococci-like organisms were selected. Twenty-four Lactococcus garvieae isolates from sand bedding and 18 isolates from quarter milk were comparatively studied using a genotypic approach. RAPD (random amplification of polymorphic DNA) PCR and REP (repetitive element palindromic) PCR experiments highlighted a similar electrophoretic profile. When genes belonging to the core genome of L. garvieae were tested through a MLRT (multilocus restriction typing), we again observed that all L. garvieae isolates coming from sand bedding and milk shared a common profile, distinguishable from previously studied representative L. garvieae strains. These data indicate that the L. garvieae isolated from sand bedding and milk originated from a few strains adapted to persist in the same habitat. This supports the hypothesis that sand bedding can represent a reservoir of L. garvieae strains and be a potential vehicle for their dissemination in dairy farms.Lactococcus garvieae est maintenant consid\ue9r\ue9 comme une esp\ue8ce d\u2019importance clinique chez l\u2019humain et en m\ue9decine v\ue9t\ue9rinaire. L\u2019objectif de cette \ue9tude consistait \ue0 \ue9valuer la pr\ue9sence de cet agent pathog\ue8ne dans de la liti\ue8re de sable et des \ue9chantillons de lait. Deux fermes du Minnesota qui pr\ue9sentaient des probl\ue8mes de mammite clinique et subclinique provoqu\ue9e par des organismes de type streptococcus ont \ue9t\ue9 s\ue9lectionn\ue9es. Vingt-quatre isolats de Lactococcus garvieae de la liti\ue8re de sable et 18 isolats de lait du pis ont \ue9t\ue9 \ue9tudi\ue9s de mani\ue8re comparative \ue0 l\u2019aide d\u2019une approche g\ue9notypique. Des exp\ue9riences en RAPD (\uab random amplification of polymorphic DNA \ubb) et en REP (\uab repetitive element palindromic \ubb) PCR mettaient en \ue9vidence des profils \ue9lectrophor\ue9tiques similaires. Lorsque les g\ue8nes appartenant au g\ue9nome central de L. garvieae \ue9taient test\ue9s par MLRT (\uab multilocus restriction typing \ubb), les auteurs observaient encore que tous les isolats de L. garvieae provenant de la liti\ue8re de sable et du lait partageaient un profil commun, distinctif de celui de souches de L. garvieae repr\ue9sentatives, \ue9tudi\ue9es pr\ue9c\ue9demment. Ces donn\ue9es indiquent que L. garvieae isol\ue9 de la liti\ue8re de sable et du lait proviennent d\u2019un nombre limit\ue9 de souches adapt\ue9es pour persister dans le m\ueame habitat. Ceci appuie l\u2019hypoth\ue8se que la liti\ue8re de sable peut constituer un r\ue9servoir de souches de L. garvieae et un v\ue9hicule de leur diss\ue9mination dans les fermes laiti\ue8res

Antimicrobial susceptibilities and random amplified polymorphic DNA-PCR fingerprint characterization of Lactococcus lactis ssp. Iactis and Lactococcus garvieae isolated from bovine intramammary infections

In total, 181 streptococci-like bacteria isolated from intramammary infections (IMI) were submitted by a veterinary clinic to Quality Milk Production Services (QMPS, Cornell University, Ithaca, NY). The isolates were characterized by sequence analysis, and 46 Lactococcus lactis ssp. lactis and 47 Lactococcus garvieae were tested for susceptibility to 17 antibiotics. No resistant strains were found for \u3b2-lactam antibiotics widely used in clinical practice (penicillin, ampicillin, and amoxicillin), and all minimum inhibitory concentrations (MIC) were far from the resistance breakpoints. Eight strains had MIC intermediate to cefazolin. The random amplification of polymorphic DNA (RAPD)-PCR fingerprint patterns showed a slightly higher heterogeneity for Lc. lactis ssp. lactis isolates than for Lc. garvieae isolates