Central Environmental and Food Science Research Institute

Budapest, Hungary

Central Environmental and Food Science Research Institute

Budapest, Hungary
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Szalontai H.,Eszterházy Károly College | Adanyi N.,Central Environmental and Food Science Research Institute | Kiss A.,Eszterházy Károly College
New Biotechnology | Year: 2014

The regular consumption of foods containing probiotic bacteria has beneficial physiological effects on the health and the digestion system. There is a need for novel analytical approaches for the determination of these bacteria that are faster than the classical plate counting method. For this purpose, two label-free biosensors were investigated and presented in this paper: Quartz Crystal Microbalance (QCM) and Optical Waveguide Lightmode Spectroscopy (OWLS) based direct immunosensors were developed for real-time direct detection of probiotic bacteria in fermented dairy products. Bifidobacterium bifidum O1356 and Lactobacillus acidophilus O1132 were detected by polyclonal anti- B. bifidum IgG and anti- L. acidophilus IgG immobilized on the sensors' surface.Sulfo-LC-SPDP cross linking agent was used to bind antibodies to the gold surface of the QCM's AT-cut quartz wafer. Concerning OWLS, antibodies were covalently bound to the amino groups of the silanized surface of the waveguide by glutaraldehyde. The dynamic measuring range was found between 1.0E+3 and 5.0E+5CFUmL-1 in 100 fold diluted fermented milk products by QCM and with OWLS. Considering the current legislation of the probiotic content in probiotic products, the two developed immunosensors can be applied for rapid quantification of L. acidophilus and B. bifidum in fermented milk. These examinations offer effective alternatives to the microbiological plate counting method. © 2014 Elsevier B.V.

Boka B.,Eszterházy Károly College | Adanyi N.,Central Environmental and Food Science Research Institute | Szamos J.,Central Environmental and Food Science Research Institute | Virag D.,Eszterházy Károly College | Kiss A.,Eszterházy Károly College
Enzyme and Microbial Technology | Year: 2012

The novel putrescine oxidase based amperometric biosensor selectively measures putrescine, which can be considered as an indicator of microbial spoilage. Putrescine oxidase (PUOX, EC was isolated from Kocuria rosea (Micrococcus rubens) by an improved and simplified purification process. Cells were grown on brain heart infusion medium supplemented with putrescine. Cell-free extract was prepared in Tris buffer (pH 8.0) by Bead-beater. A newly elaborated step based on three-phase partitioning (TPP) was applied in the purification protocol of PUOX.The purified enzyme was immobilized on the surface of a spectroscopic graphite electrode in redox hydrogel with horseradish peroxidase, Os mediator and poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as crosslinking agent. This modified working electrode was used in wall-jet type amperometric cell together with the Ag/AgCl (0.1M KCl) reference electrode and a platinum wire as auxiliary electrode in flow injection analysis system (FIA). Hydrogel composition, pH and potential dependence were studied. Optimal working conditions were 0.45mLmin-1 flow rate of phosphate buffer (66mM, pH 8.0) and +50mV polarizing potential vs. Ag/AgCl. The linear measuring range of the method was 0.01-0.25mM putrescine, while the detection limit was 5μM. Beer samples were investigated by the putrescine biosensor and the results were compared by those of HPLC reference method. © 2012 Elsevier Inc.

Boka B.,Eszterházy Károly College | Adanyi N.,Central Environmental and Food Science Research Institute | Virag D.,Eszterházy Károly College | Frebort I.,Palacky University | Kiss A.,Eszterházy Károly College
Electroanalysis | Year: 2013

An enzyme-based amperometric biosensor was developed for the rapid determination of adenine in biological and food samples. Recombinant adenine deaminase (EC from Schizosaccharomyces pombe was co-immobilized on graphite electrode with xanthine oxidase (EC, peroxidase (EC and an Os mediator. Optimal working conditions were pH7.0 and -150mV vs. Ag/AgCl. The novel method was characterized by a detection limit of 1μM and a linear measuring range of 0.005-0.1mM. Different beer and tea samples were analyzed by the newly elaborated adenine biosensor. The results obtained correlate with the adenine content measured by the reference HPLC method. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hansen L.S.,University of Aarhus | Lovei G.L.,University of Aarhus | Szekacs A.,Hungarian Academy of Sciences | Szekacs A.,Central Environmental and Food Science Research Institute
Pest Management Science | Year: 2013

Background: The effect of transgenic maize (Zea mays L.) containing a lepidopteran-specific Bt toxin on a stored-product pest, Sitophilus zeamais Motschulsky, and its parasitoid, Lariophagus distinguendus Förster, was examined in the laboratory to test the impact of transgenic maize on stored-product pests and their biological control. Results: Weevils were not harmfully affected by transgenic Bt maize in their development characteristics (development time, body mass), and females emerging from transgenic maize kernels were larger. However, significantly fewer parasitoid females emerged from weevils that developed in transgenic kernels, although parasitoids did not develop more slowly and were not different in size or mass from their conspecifics emerging from hosts in non-transgenic maize kernels. Conclusion: The emergence of female parasitoids was reduced in transgenic Bt maize, and this effect cannot be explained by the known lepidopteran-specific toxicity of Bt Cry1Ab toxin. © 2012 Society of Chemical Industry.

Baranyi J.,UK Institute of Food Research | Csernus O.,Central Environmental and Food Science Research Institute | Beczner J.,Central Environmental and Food Science Research Institute
International Journal of Food Microbiology | Year: 2014

The purpose of this paper was to develop a predictive model for the effect of temperature and water activity on the growth rate of Aspergillus niger and to determine the sources of the error when the model is used for prediction. Parallel mould growth curves, derived from the same spore batch, were generated and fitted to determine their growth rate. The variances of replicate ln(growth-rate) estimates were used to quantify the experimental variability, inherent to the method of determining the growth rate. The environmental variability was quantified by the variance of the respective means of replicates. The idea is analogous to the "within group" and "between groups" variability concepts of ANOVA procedures.A (secondary) model, with temperature and water activity as explanatory variables, was fitted to the natural logarithm of the growth rates determined by the primary model. The model error and the experimental and environmental errors were ranked according to their contribution to the total error of prediction.Our method can readily be applied to analysing the error structure of predictive models of bacterial growth models, too. © 2013 Elsevier B.V.

Cserhati M.,Szent Istvan University | Kriszt B.,Szent Istvan University | Krifaton C.,Szent Istvan University | Szoboszlay S.,Szent Istvan University | And 4 more authors.
International Journal of Food Microbiology | Year: 2013

Mycotoxins are secondary fungal metabolites that may have mutagenic, carcinogenic, cytotoxic and endocrine disrupting effects. These substances frequently contaminate agricultural commodities despite efforts to prevent them, so successful detoxification tools are needed. The application of microorganisms to biodegrade mycotoxins is a novel strategy that shows potential for application in food and feed processing. In this study we investigated the mycotoxin degradation ability of thirty-two Rhodococcus strains on economically important mycotoxins: aflatoxin B1, zearalenone, fumonisin B1, T2 toxin and ochratoxin A, and monitored the safety of aflatoxin B1 and zearalenone degradation processes and degradation products using previously developed toxicity profiling methods. Moreover, experiments were performed to analyse multi-mycotoxin-degrading ability of the best toxin degrader/detoxifier strains on aflatoxin B1, zearalenone and T2 toxin mixtures. This enabled the safest and the most effective Rhodococcus strains to be selected, even for multi-mycotoxin degradation. We concluded that several Rhodococcus species are effective in the degradation of aromatic mycotoxins and their application in mycotoxin biodetoxification processes is a promising field of biotechnology. © 2013 Elsevier B.V.

Adanyi N.,Central Environmental and Food Science Research Institute | Majer-Baranyi K.,Central Environmental and Food Science Research Institute | Nagy A.,Central Environmental and Food Science Research Institute | Nemeth G.,Central Environmental and Food Science Research Institute | And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2013

Abstract Label-free, optical waveguide lightmode spectroscopy (OWLS) based immunosensors were developed for vitellogenin (Vtg) determination in carp (Cyprinus carpio). Purified polyclonal serum raised in rabbits against lipovitellin (Lpv) purified from carp ovary and shown to fully cross-react with Vtg was applied both in direct and indirect measurement formats, and analytical features (limit of detection, specificity, matrix effects) were investigated. The direct OWLS immunosensor and the sandwich ELISA assay developed showed linear measuring range in 600-12,000 ng mL?1 and 200-3000 ng mL?1 Lpv concentrations in standard solutions, respectively. The competitive immunosensor allowed a sensitive detection range for Lpv between 3 and 100 ng mL?1. Vtg content in blood and liver samples from male and female carp were determined by indirect OWLS. To reduce the matrix effect, calibration curves were obtained using Vtg-free blood and liver samples from male carp spiked with Lpv. Vtg levels in the liver of female carp was lower than determined in the blood samples, therefore, blood occurs to be a more proper tissue to monitor elevated Vtg in male carp due to possible exposure to water-contaminating endocrine disrupting chemicals. © 2012 Elsevier B.V. All rights reserved.

Krifaton C.,Szent Istvan University | Kriszt B.,Szent Istvan University | Risa A.,Szent Istvan University | Szoboszlay S.,Szent Istvan University | And 6 more authors.
Journal of Hazardous Materials | Year: 2013

The aim of this study was to screen microbes for their zearalenone degrading potential and to select microbes whose activities do not create toxic or endocrine disrupting metabolites. Bioluminescent bioreporters (Saccharomyces cerevisiae BLYES and BLYR) were successfully used to monitor toxin degradation; the results of zearalenone biodegradation experiments were confirmed by parallel chemical analysis (HPLC-FLD) and immunoanalytical (ELISA) tests. Using the BLYES/BLYR bioreporters, the most appropriate microbes (ones that produced minimal toxic products and products with lower estrogenic potential) could be selected. The most promising strains belong to Streptomyces and Rhodococcus genera. Our findings demonstrate the benefit of using biological tests beside the analytical method, since bioreporters were able to monitor the samples for toxicity and estrogenic potential even after substantial degradation. We conclude that the BLYES/BLYR bioreporter system is a cost effective, fast and reliable tool for screening zearalenone-degrading microbes. © 2012 Elsevier B.V.

Paszti-Gere E.,Szent Istvan University | Barna R.F.,Szent Istvan University | Kovago C.,Szent Istvan University | Szauder I.,Cardiosens Center | And 4 more authors.
Inflammation | Year: 2015

The effect of oxidative stress on barrier integrity and localization of transmembrane serine proteinase 2 (TMPRSS2) were studied using porcine epithelial IPEC-J2 cells on membrane inserts. Increased paracellular permeability of FITC-dextran 4 kDa (fluorescence intensity 43,508 ± 2,391 versus 3,550 ± 759) and that of gentamicin (3.41 ± 0.06 % increase to controls) were measured parallel with the reduced transepithelial electrical resistance (23.3 ± 4.06 % decrease) of cell layers 6 h after 1 h 1 mM H2O2 treatment. The immunohistochemical localization of adherens junctional β-catenin was not affected by reactive oxygen species (ROS) up to 4 mM H2O2. Peroxide-triggered enhanced paracellular permeability of IPEC-J2 cell layer was accompanied by predominantly cytoplasmic occurrence of TMPRSS2 embedded in cell membrane under physiological conditions. These results support that ROS can influence paracellular gate opening via multifaceted mode of action without involvement of β-catenin redistribution in adherens junction. Altered distribution pattern of TMPRSS2 and relocalized transmembrane serine protease activity may contribute to weakening of epithelial barrier integrity under acute oxidative stress. © 2014, Springer Science+Business Media New York.

Banati D.,Central Environmental and Food Science Research Institute
Journal of the Science of Food and Agriculture | Year: 2014

Food safety has been a growing concern among European Union (EU) citizens over the last decades. Despite the fact that food has never been safer, consumers are considerably uncertain and increasingly critical about the safety of their food. The introduction of new principles, such as the primary responsibility of producers, traceability, risk analysis, the separation of risk assessment and risk management provided a more transparent, science-based system in Europe, which can help to restore consumers' lost confidence. The present EU integrated approach to food safety 'from farm to fork' aims to assure a high level of food safety within the EU. © 2014 Society of Chemical Industry.

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