Impact of a selected Debaryomyces hansenii strain's inoculation on the quality of Sardinian fermented sausages.

Dominant yeast species in Salsiccia Sarda, a traditional fermented sausage produced in Sardinia (Italy), were evaluated through the monitoring three typical production processes. Six different species were identified by molecular techniques, but Debaryomyces (D.) hansenii proved to be dominant. A D. hansenii strain was selected according to its technological features and used in three experimental sausage productions at farm scale with the aim to evaluate its antifungal effect. In all cases, two batches were inoculated with a previously selected autochthonous starter cultures (Lactobacillus plantarum and Staphylococcus xylosus), whereas two batches were left to spontaneous fermentation. D. hansenii was inoculated on the sausages surface by brushing after the sausages drying, by immersion in a yeast suspension after the stuffing, or, alternatively, casings were dipped in a yeast suspension before the dough stuffing. Microbial counts in the sausages core did not appear to be affected by D. hansenii application, while outcomes obtained for casings appeared soundly diversified. Brushing on the sausages surface at the onset of fermentation proved to be the best approach to treat sausages. Yeast inoculation exerted a noteworthy anti-mould effect, independently of the mode of application and, on the other hand, did not affect the overall quality and typical features of the product.

Novel starters for old processes: use of Saccharomyces cerevisiae strains isolated from artisanal sourdough for craft beer production at a brewery scale.

The deliberate inoculation of yeast strains isolated from food matrices such as wine or bread, could allow the transfer of novel properties to beer. In this work, the feasibility of the use of baker's yeast strains as starters for craft beer production has been evaluated at laboratory and brewery scale. Nine out of 12 Saccharomyces cerevisiae strains isolated from artisanal sourdoughs metabolized 2 % maltose, glucose and trehalose and showed growth rates and cell populations higher than those of the brewer's strain Safbrew-S33. Analysis of allelic variation at 12 microsatellite loci clustered seven baker's strains and Safbrew-S33 in the main group of bread isolates. Chemical analyses of beers produced at a brewery scale showed significant differences among the beers produced with the baker's strain S38 or Safbrew-S33, while no significant differences were observed when S38 or the brewer's strain Safbrew-F2 was used for re-fermentation. The sensory profile of beers obtained with S38 or the brewer's yeasts did not show significant differences, thus suggesting that baker's strains of S. cerevisiae could represent a reservoir of biodiversity for the selection of starter strains for craft beer production.

Rapid prenatal diagnosis of common chromosome aneuploidies by QF-PCR, results of 9 years of clinical experience.

BACKGROUND: Despite being deliberately targeted to common chromosome aneuploidies, the rapid quantitative fluorescent polymerase chain reaction (QF-PCR) tests can detect the majority of chromosome abnormalities in prenatal diagnosis. The main advantages of this assay are low cost, speed and automation allowing large-scale application. METHODS: We developed a QF-PCR test that was applied on 43 000 clinical samples reporting results in 24 h. Most common indications were biochemical risk (32%) and advanced maternal age (30%). Samples were also tested by cytogenetic analysis and the results compared. RESULTS: Aneuploidies involving chromosomes 21, 18, 13, X and Y were detected with 100% specificity. Several cases of partial trisomies and mosaicism were also identified. Overall 95% of clinically relevant abnormalities were readily detected and termination of affected pregnancies could be performed without waiting for the cytogenetic results. CONCLUSIONS: Our study supports the possibility of reducing the load of prenatal cytogenetic tests if the pregnancies are carefully monitored by non-invasive screening. In case of abnormal QF-PCR results, medical action can be taken within few hours from sampling. In cases of negative QF-PCR results, cytogenetic analyses might only be performed for fetuses with ultrasound abnormalities. In countries where large-scale cytogenetic tests are not available, QF-PCR may be used as the only prenatal diagnostic procedure.

Rapid prenatal diagnosis by QF-PCR: evaluation of 30,000 consecutive clinical samples and future applications.

Rapid prenatal diagnoses of major chromosome abnormalities can be performed on a large scale using highly polymorphic short tandem repeats (STRs) amplified by the quantitative fluorescent polymerase chain reaction (QF-PCR). The assay was introduced as a preliminary investigation to remove the anxiety of the parents waiting for the results by conventional cytogenetic analysis using amniotic fluid or chorionic cells. However, recent studies, on the basis of the analyses of several thousand samples, have shown that this rapid approach has a very high rate of success and could reduce the need for cytogenetic investigations. Its high efficiency, for example, allows early interruption of affected fetuses without the need of waiting for completion of fetal karyotype. The main advantages of the QF-PCR are its accuracy, speed, automation, and low cost that allows very large number of samples to be analyzed by few operators. Here, we report the results of using QF-PCR in a large series of consecutive clinical cases and discuss the possibility that, in a near future, it may even replace conventional cytogenetic analyses on selected samples.