Publications (33) View all
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Article: High content of biogenic amines in Pecorino cheeses.
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ABSTRACT: Pecorino refers to Italian cheeses made exclusively from raw or pasteurized ewes' milk, characterized by a high content of fat matter and it is mainly produced in the Middle and South of Italy by traditional procedures. The autochthonous microbiota plays an important role in the organoleptic traits of Pecorino cheese and it can influence biogenic amines (BA) content. The aim of this study was to characterize from microbiological and chemical point of view 12 randomly purchased commercial cheeses produced in Abruzzo region. Moreover, the BA content and the bacteria showing a decarboxylating activity were detected. For this purpose, a real-time quantitative PCR (qPCR) was applied to evaluate histamine and tyramine-producers. The samples were well differentiated for microbial groups composition, such as aerobic mesophilic bacteria, Enterobacteriaceae, coagulase-negative staphylococci, yeasts, enterococci, mesophilic and thermophilic lactobacilli. Pathogens such as Salmonella spp., Listeria monocytogenes and Escherichia coli O157:H7 were absent in all samples. In most samples the content of BA resulted to be high, with prevalence of histamine and tyramine. In particular, total BA content reached 5861 mg/kg in Pecorino di Fossa cheese. The qPCR method resulted to be very useful to understand the role of autochthonous Pecorino cheese microbiota on BA accumulation in many different products. In fact, since the ability of microorganisms to decarboxylate aminoacids is highly variable being in most cases strain-specific, the detection of bacteria possessing this activity is important to estimate the risk of BA cheese content.Food Microbiology 05/2013; 34(1):137-44. · 3.28 Impact Factor -
Article: Yeast biota associated to naturally fermented table olives from different Italian cultivars.
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ABSTRACT: The yeast communities associated with the fermentation of six different cultivars of Italian table olives were studied. Molecular identification of a total of 117 isolates was achieved by a combination of PCR-RFLP of the 5.8S ITS rRNA region and sequencing of the D1/D2 domain of the 26S rRNA gene. In addition, the isolates were differentiated by RAPD-PCR. The yeast population was also monitored by a culture-independent method based on PCR-DGGE analysis. This combined strategy resulted to be a powerful and reliable tool to investigate table olives yeast ecology and revealed that Saccharomyces cerevisiae was present in all the processed olives. Moreover, strains were characterized on the basis of different properties of technological interest. In particular, β-glucosidase, catalase, pectinolytic, xylanolytic, esterase and lipase activities were investigated and the ability to grow up in presence of different salt concentration (5-7.5-10-14-20% w/v) was evaluated. The majority of strains showed catalase activity and none of them expressed pectinolytic, xylanolytic, esterase or lipase activities. Six strains belonging to Pichia galeiformis and six strains of Wicheramomyces anomalus showed β-glucosidase activity. Only 10 S. cerevisiae strains were able to grow in presence of 14% NaCl. The obtained results offer valuable information on yeast population biodiversity and dynamics in naturally fermented Italian table olives and show the potential use of some yeast strains, besides lactic acid bacteria, as a part of mixed starter cultures for table olive fermentation.International journal of food microbiology 12/2012; 161(3):203-208. · 3.01 Impact Factor -
Article: Detection of yessotoxin by three different methods in Mytilus galloprovincialis of Adriatic Sea, Italy.
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ABSTRACT: Samples of Mytilus galloprovincialis collected from shellfish aquaculture plans located in the Adriatic Sea were analysed for yessotoxin (YTX) by three methods, in vivo (Mouse Bioassay, MBA), in vitro (functional assay) and chemical test (Liquid Chromatography-Mass Spectrometry, LC-MS/MS). As YTX coexists with other phycotoxins in shellfish, namely the diarrhoetic shellfish poisoning, okadaic acid, dinophysistoxins, pectenotoxins, and azaspirazids, the MBA is not completely satisfactory because it is difficult to identify which toxin causes the death of the mice. So, the two other techniques were proposed to detect and quantify YTX and its analogues in order to avoid this problem. The global results showed no difference among the three methods and the correlation between the functional assay and LC-MS/MS was positive (Spearman r=0.72). Both analytical methods demonstrated advantages; the functional assay is specific, very sensitive and correlates well with real toxicity, whereas LC-MS/MS is convenient because it allows the detection of YTX and some analogues which are currently included in the EU regulation. For this reason LC-MS/MS will become the official method starting 1st January 2015 (Regulation 15/2011/EU). Only four samples exceeded the current EU regulation limit of 1mg of YTX equivalent kg(-1). However, all samples belonged to a monitoring program and they were not suitable for consumers.Chemosphere 10/2012; · 3.21 Impact Factor -
Article: Yessotoxin determination in Mytilus galloprovincialis revealed by an in vitro functional assay.
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ABSTRACT: Yessotoxins (YTXs) are polycyclic ether compounds produced by phytoplanktonic dinoflagellates and accumulated in filter-feeding shellfish. Mouse bioassay is still the official method to detect these toxins, even if it is lacking of specificity and sensitivity. Moreover, there is growing resistance against the use of animal experiments. Many efforts have been made to determine YTXs with other methods. The detection of YTX using a functional assay allows its quantification with an automated and repetitive technique at concentrations in the range of the 1 mg of YTX equivalent/kg European regulatory limit. In this study, an in vitro functional assay based on YTX treatment of MCF-7 cells and resulting in the accumulation of a 100-kDa fragment of E-cadherin was developed on samples of Mytilus galloprovincialis collected from the Adriatic Sea, Italy, along the coasts of Abruzzo, Molise, and Emilia Romagna regions. The YTX concentrations ranged from 0.2 to 1.8 mg of YTX equivalent/kg. The occurrence of levels exceeding the above mentioned limit was observed only in samples of Emilia Romagna region. This last result could represent a risk for human health, but these shellfish were not intended to consumers, because they belonged to a preventive monitoring program.Environmental Science and Pollution Research 09/2012; · 2.65 Impact Factor -
Article: Detection of Brettanomyces spp. in Red Wines Using Real-Time PCR.
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ABSTRACT: The question if the "Brett character" is a favorable wine attribute is one of the most controversial issues and it is currently addressed by many researches. Actually, the presence of Brettanomyces/Dekkera in wine during barrel aging is often associated to detrimental organoleptic characteristics depending on the release of volatile phenols (for example, 4-ethylphenol and 4-ethylguaiacol); for that reason the possibility to rapidly detect the yeast at the early stage of wine production could allow preventive actions to reduce wine spoilage. In this work, 25 and 5 samples from conventional and organic vineyards, respectively, all suspected to be spoiled by Brettanomyces/Dekkera spp., were analyzed using both culture-dependent and culture-independent techniques. In particular, a DNA extraction protocol and a real-time quantitative PCR (qPCR) assay to directly detect and quantify B. bruxellensis were optimized. Results showed that B. bruxellensis was present in 22 of 30 samples, ranging from 10 to 10(4) CFU/mL, lower values being found in organic wines (10 to 10(2) CFU/mL). Overall, qPCR was proved to be a useful and valuable wine control system, since 12 samples were recorded as positive for yeast presence when analyzed by qPCR and negative in case of plate count analyses. Practical Application: Brettanomyces cells were detected using a qPCR method, optimized in this study, which allows to obtain results quickly.Journal of Food Science 08/2012; 77(9):M545-9. · 1.66 Impact Factor
