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Gil-Serna J.,Complutense University of Madrid | Patino B.,Complutense University of Madrid | Cortes L.,Laboratorio Arbitral Agroalimentario | Gonzalez-Jaen M.T.,Complutense University of Madrid | Vazquez C.,Complutense University of Madrid
International Journal of Food Microbiology | Year: 2011

Aspergillus westerdijkiae is one of the most relevant ochratoxin A (OTA) producing species within the Section Circumdati contaminating a number of agroproducts. The yeast Debaryomyces hansenii CYC 1244 was previously reported to be able to reduce growth and extracellular OTA produced by A. westerdijkiae. In this work, we examined several mechanisms possibly involved in this OTA reduction in in vitro experiments. OTA biosynthesis was evaluated by quantitation of expression levels of pks (polyketide synthase) and p450- B03 (cytochrome p450 monooxygenase) genes using newly developed and specific real time RT-PCR protocols. Both genes showed significant lower levels in presence of D. hansenii CYC 1244 suggesting an effect on regulation of OTA biosynthesis at transcriptional level. High levels of removal of extracellular OTA were observed by adsorption to yeast cell walls, particularly at low pH (98% at pH 3). On the contrary, no evidences were obtained of absorption of OTA into yeast cells or the production of constitutively expressed enzymes that degrade OTA by D. hansenii CYC 1244. These results described the potential of this yeast strain as a safe and efficient biocontrol agent to decrease OTA in A. westerdijkiae and two important mechanisms involved which may permit its application at different points of the food chain. © 2011. Source

Gil-Serna J.,Complutense University of Madrid | Patino B.,Complutense University of Madrid | Cortes L.,Laboratorio Arbitral Agroalimentario | Gonzalez-Jaen M.T.,Complutense University of Madrid | Vazquez C.,Complutense University of Madrid
Food Microbiology | Year: 2015

Aspergillus steynii and Aspergillus westerdijkiae are the main ochratoxin A (OTA) producing species of Aspergillus section Circumdati. Due to its recent description, few data are available about the influence of ecophysiological factors on their growth and OTA production profiles. In this work, the effect of temperature (20, 24 and 28°C) and water activity (aw) (0.928, 0.964 and 0.995) on growth, sporulation and OTA production by these fungi was examined in CYA and media prepared from paprika, green coffee, anise, grapes, maize and barley. Growth was positively affected by the highest temperature and aw values indicating that both species might be expected in warm climates or storage conditions. However, optimal growth conditions showed differences depending on the medium. OTA production was markedly affected by substrate and showed qualitative and quantitative differences. Both species, especially A.steynii, represent a great potential risk of OTA contamination due to their high production in a variety of conditions and substrates, in particular in barley and paprika-based media. Additionally, neither growth nor sporulation did result good indicators of OTA production by A.steynii or A.westerdijkiae; therefore, specific and highly-sensitive detection methods become essential tools for control strategies to reduce OTA risk by these species. © 2014 Elsevier Ltd. Source

Esteban-Fernandez D.,Humboldt University of Berlin | Mirat M.,Laboratorio Arbitral Agroalimentario | De La Hinojosa M.I.M.,Laboratorio Arbitral Agroalimentario | Alonso J.I.G.,University of Oviedo
Journal of Agricultural and Food Chemistry | Year: 2012

Sample preparation continues being a key factor to obtain fast and reliable quantification of Hg species. Assisted procedures enhance the efficiency and reduce the extraction time; however, collateral species transformations have been observed. Moreover, differential interconversions have been observed even between similar matrixes, which introduce an important uncertainty for real sample analysis. Trying to minimize Hg species transformations, we have tested a soft ultrasound-assisted extraction procedure. Species quantification and transformations have been evaluated using double spike isotope dilution analysis (IDA) together with gas chromatography inductively coupled plasma mass spectrometry (GC-ICP-MS) for a CRM material (Tort-2) and shark and swordfish muscle samples. Optimum extraction solution and sonication time led to quantitative extraction and accurate determination of MeHg and IHg in a short time, although different behaviors regarding species preservation were observed depending on the sample. Negligible species transformations were observed in the analysis of the CRM, while a small but significant demethylation factor was observed in the case of real samples. In comparison with other extraction procedures, species transformations became smaller, and fewer differences between fish species were found. Similar results were obtained for fresh and lyophilized samples of both fish samples, which permit one to analyze the fresh sample directly and save time in the sample preparation step. The high grade of species preservation and the affordability of the extraction procedure allow one to obtain accurate determinations even for routine laboratories using quantification techniques, which do not estimate species transformations. © 2012 American Chemical Society. Source

Cabanero A.I.,Laboratorio Arbitral Agroalimentario | Ruperez M.,Laboratorio Arbitral Agroalimentario
Rapid Communications in Mass Spectrometry | Year: 2012

RATIONALE The cider market is an important sector of the food industry in certain regions. Adulteration of cider can happen in several ways: for example, by the addition of sugar, or of exogenous CO 2 to certain types of cider. Because such practices are not allowed by either Spanish legislation or the legislation of other countries, it is essential to study possible methods to detect these unauthorized practices. For this purpose a procedure was required to study the stable carbon isotopic composition of CO 2 in cider. METHODS A liquid sample of cider was transferred to a vial and CO 2 from the headspace of the vial was analyzed using a peripheral device interfaced to an isotope ratio mass spectrometer. Separation of the CO 2 from water and ethanol was achieved using a gas chromatography column located in the peripheral device. RESULTS The values for repeatability and reproducibility obtained indicated the robustness of the method, which is required for routine analysis. Ninety cider samples from various origins were analyzed, most of which showed a 13C content consistent with the declared origin. The δ 13C ranged from -24.80° to -20.89° for ciders with endogenous carbon dioxide (-22.74 ± 0.79°) and -37.13° to -26.00° if industrial CO 2 was added. Several samples were also suspected of C4 sugar addition prior to the fermentation. CONCLUSIONS A fast, accurate and simple method for cider adulteration detection was developed. The addition of exogenous CO 2 as well as C4 sugar addition prior to fermentation could be detected. The method showed advantages over existing methods in term of simplicity (no sample preparation and very long-term stability of the sample), speed (less than 10 min/sample) and precision ((r ≤0.32 and R a;circ0.42). Copyright © 2012 John Wiley & Sons, Ltd. Source

Campo J.L.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria | Cabezas R.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria | Torres O.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria | Briones I.G.,Laboratorio Arbitral Agroalimentario | Alonso C.,Laboratorio Arbitral Agroalimentario
Archiv fur Geflugelkunde | Year: 2013

The objective of this study was to compare the external, internal, and nutritional quality of eggs, and the welfare of non-beak-trimmed hens housed in three different non-cage systems: indoor litter floor pens (L), outdoor with pasture access (OP), and outdoor without pasture access (O). The external egg quality was analyzed for egg weight, shape index, specific gravity, incidence of cracked and dirty eggs, and shell colour, whereas the internal egg quality was analyzed for yolk colour, and Haugh units, and the nutritional egg quality was analyzed for n-3 fatty acids, cholesterol, and vitamins A and E. The hen welfare was evaluated using heterophil to lymphocyte ratio, duration of tonic immobility, and incidence of eggs with pink shells, brown spotted shells, or internal inclusions. Four Spanish breeds with different genetic background (white-, tinted-, brown-, and dark brown-shell egg layers) were used. A total of 1,140 fresh eggs and 360 hens were used. Additionally, 96 eggs were chosen to analyze their nutritional quality. Housing system × breed interaction was significant for egg weight (P < 0.001), shape index (P < 0.001), specific gravity (P < 0.001), incidence of cracks (P < 0.01), shell colour (P < 0.001), yolk colour (P < 0.001), and Haugh units (P < 0.001). There was no significant interaction for the incidence of dirty eggs and the nutritional egg quality. The OP housing system had darker yolk colour in all breeds. The O outdoor system only with access to sand had higher incidence of dirty eggs, whereas the L system had lighter shell colour, suggesting a commercial disadvantage of this system to market darker brown eggs. Eggs obtained from OP hens were characterized by a significant higher n-3 and linolenic fatty acid content of yolk. There were no significant differences for cholesterol content, and vitamins A and E. There was no significant interaction for any welfare indicator. The effect of the housing system on the tonic immobility duration was not significant. The effect of the housing system on the heterophil to lymphocyte ratio was significant (P < 0.05), with heterophil to lymphocyte ratio being higher in hens housed in the OP system. Housing effect was significant for the incidence of eggs with internal inclusions (P < 0.001), hens from the O system having lower incidence. Housing system × breed interaction was significant for mortality percentage (P < 0.05), mortality being highest (30%) in the OP system for the Prat breed. Our study with Spanish breeds demonstrated that none of the tested housing systems were in general superior to the other systems, each system having its unique challenges. © Verlag Eugen Ulmer, Stuttgart. Source

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