This review is an account of experiences of two research teams (from Italy to Spain); the leading idea is the following: yeasts represent valuable sources in food science and microbiology and are a kind of food factories, because of the potentiality of whole cells or for their produced compounds. This review covers three major areas: the first section addresses the role of yeasts as starter cultures with a special focus on wine. The second section is an update on probiotic yeasts. Finally, the focus of the last section is on enzymes produced by yeasts, with a short description of the removal of mycotoxin.

Historically, brewing beer came from uncontrolled spontaneous fermentations; nowadays, spontaneous fermentation is still used in speciality products such as Belgian acid beers (e.g., lambic, gueze and Rodenbach) or in various traditional beers worldwide. On the other hand, industrial fermentations sometimes require a combination of phenotypic traits that might not be commonly encountered in nature. In some cases, the demand for increased productivity, as well as changing consumer preferences, leads to a great interest towards improvement and/or design new strains or yeast variants. This review addresses the following topics: controlled and uncontrolled fermentation, advances in the selection of novel, nonconventional, and superior strains for beer.

The selection of a starter is a complex process, involving different steps, like a preliminary characterization under laboratory conditions, the selection of the most promising strains, a lab validation and the final validation in a large-scale fermentation; the selection of a functional starter includes a further step, dealing with the assessment of the functional traits. This paper proposes a case study on how to use a step-by-step approach, based on some rapid protocols, to select promising starter cultures with probiotic abilities. Nine strains, isolated from a commercial preparation, were studied in relation to some enzymatic activities (slime and acetoin production, reduction of nitrates, proteolytic activity and hydrolysis of tributyrin), technological (acidification and growth at different temperatures, pHs and salt amounts) and probiotic traits (hydrophobicity, co-aggregation towards Salmonella sp. and Escherichia coli, survival at pH 2.5 and in presence of bile salts, antibiotic resistance) and compared to some collection isolates. As a final step, a multivariate approach was used to select the most promising isolates. The isolates from the commercial preparation were able to perform the fermentation (e.g. acidification) at low temperatures with some interesting traits in terms of bioactivity towards E. coli O157:H7, whilst some interesting probiotic traits in terms of hydrophobicity and survival in conditions that mimicked the gut were found for the collection isolates.

BACKGROUND: Olive mill wastewaters (OMWWs) possess a strong environmental impact; the use of fungi as tools for bioremediation could be a promising method. RESULTS: Twenty-nine fungi were grown on minimal media supplemented with five different kinds of OMWWs (5–15%). Radial growth was assessed for 21 days and the data were modelled through the Dantigny-logistic like function to estimate , i.e. the time to attain half of the maximum diameter. Growth on potato dextrose agar and water agar (WA, minimal medium without supplementation) was used as reference. The differences in between PDA/WA and minimal media with OMWWs were modelled through a multi-factorial ANOVA, using the concentration of OMWW, the kind of wastes and fungi as categorical predictors. Finally, a principal component analysis was run to group and divide resistant and sensitive fungi. Some fungi experienced a positive , thus suggesting an inhibition by OMWW, whereas other isolates were enhanced. CONCLUSIONS: Some isolates (for example Aspergillus ochraceus) showed a promising trend and could be possible candidates for a validation on a real scale.

The aim of this study was to characterize the in vitro antimicrobial susceptibility profile of Coliform and Pseudomonas species strains to 10 antibiotics (Vancomycine, Ciprofloxine, Tetracyclin, Chloramphenicol , Erythromycin, Streptomycine, Gentamycine , Ampicilline, trimethoprimsulfamethoxazole and Clarithromycin) that could potentially be used in clinical therapy. MIC was determined for antibiotics in Mueller-Hinton (MH) agar plates, by using E-test strips (Liofilchem, Roseto degli Abruzzi, Italy). MIC was read after 24 h of incubation at 37°C. The both strains were more susceptible to Ciprofloxine (MIC values: Coliform, 0.002 μg/mL; and Pseudomonas, 0.047 μg/mL). No strain of Pseudomonas was found sensitive to Chloramphenicol, Erythromycin, Ampicilline, trimethoprim-sulfamethoxazole and Clarithromycin, contrary to coliform, which was found resistant to those antibiotics with MIC values ranged between 0.38 and 128 μg/mL . Gentamycine (MIC values: Coliform, 0.125μg/mL; and Pseudomonas, 0.50 μg/mL), Tetracyclin (MIC values: Coliform, 1.00 μg/mL; and Pseudomonas, 0.75 μg/mL) and Streptomycine (MIC values: Coliform, 0.75 μg/mL; and Pseudomonas, 2.5 μg/mL) were also active against Coliform and Pseudomonas strains, while resistance to Vancomycine (no inhibition) was observed in the two strains.

The main topic of this paper is the evaluation of adhesion of propionibacteria to IPEC-J2 cells and the survival at pH 2.5 and with 0.3% bile salts added, bioactivity towards pathogens and antibiotic resistance of Propionibacterium freudenreichii subsp. shermanii, Propionibacterium jensenii, Propionibacterium acidipropionici and Propionibacterium thoenii. Adhesion to IPEC-J2 cell lines was ca. 25-35% and significantly increased with CaCl2. Moreover, propionibacteria showed a reduction of cell count of ca. 0.5% at pH 2.5 after 3 h, whereas cell count increased after 24 h with bile salts; finally, they significantly inhibited Escherichia coli O157:H7.

This paper focuses on the use of statistical Design of Experiments (DoE) to investigate the effects of two anti-lactic acid bacteria compounds on growth and metabolism of lactobacilli isolated from Italian table olives. As phenolic compounds were used p-coumaric and vanillic acids (0.0-0.4%) that were combined with salt (0.0-6.0%) and glucose (0.0-4.0%) through a Central Composite Design. As test organisms were used three strains of Lactobacillus plantarum (5 log cfu/ml); samples were stored at 37° C and cell counts and pH were evaluated periodically. The growth of lactobacilli was affected in a significant way by salt, p-coumaric and vanillic acids, being the salt the most significant factor after 24 h (short storage time), then replaced by p-coumaric acid. p-coumaric acid played also a significant role on the acidifying ability, expressed as decrease of pH of the medium: microbial metabolism, in fact, appeared as completely inhibited at 0.2% of p-coumaric acid.