A ocratoxina (OTA) é uma micotoxina que possui propriedades nefrotóxicas, hepatotóxicas, teratogênicas e carcinogênicas. No Brasil, o limite máximo permitido de OTA em vinhos foi estabelecido em 2011 e é 2 μg/L. A ocorrência desta toxina em vinhos está relacionada principalmente à presença de fungos do gênero Aspergillus nas uvas usadas para a vinificação. Deste modo, o objetivo deste estudo foi verificar a influência das etapas de elaboração de vinho Cabernet Sauvignon sobre os níveis de OTA, através de dois diferentes experimentos: (A) vinho elaborado a partir de uvas inoculadas com fungo ocratoxigênico e (B) vinho elaborado com uvas naturalmente contaminadas com OTA. Para os dois experimentos, amostras das etapas mosto, fermentação/maceração, descuba, pós-fermentação, trasfega e maturação foram coletadas em triplicata, durante um período de 5 meses. A OTA foi detectada através da técnica de cromatografia líquida de alta eficiência com detector de fluorescência (CLAE-FL) e o limite de detecção e quantificação foi de 0,06 μg/L e 0,6 μg/L, respectivamente. Durante a vinificação, as etapas que apresentaram maior percentual de redução da toxina foram descuba, pós-fermentação e trasfega. Reduções significativas nos níveis de OTA foram observadas após a conclusão da vinificação. No vinho elaborado com uvas inoculadas com fungo ocratoxigênico observou-se uma redução de 92,6%. Valor similar (92%) foi verificado no vinho produzido com uvas naturalmente contaminadas por OTA. Considerando todo o processo de vinificação, pode-se sugerir que a diminuição dos níveis de OTA foi observada principalmente, devido à adsorção da toxina à parede celular das leveduras. Além disso, a adsorção da toxina aos sólidos em suspensão presentes no vinho durante a elaboração pode ter ocorrido. / The ochratoxin A (OTA) is a mycotoxin with nephrotoxic, hepatotoxic, teratogenic and carcinogenic properties. In Brazil, the permitted maximum limits for the OTA in wines was established in 2011 and is 2 μg/L. The occurence of this toxin in wines is due mainly for presence of fungi from Aspergillus genera in grapes used for winemaking. In this way, the aim of this study was to check the influence of stages of the winemaking process of Cabernet Sauvignon grape on the OTA levels through two different experiments: (A) wine made from grapes inoculated with ochratoxigenic fungi and (B) wine made from grapes naturally contaminated with OTA. For the two experiments, samples of must, fermentation/maceration, drawn-off wine, after fermentation, racking and maturation stages were collected in triplicate, during 5 months. The OTA was detected using high-performance liquid chromatography with fluorecence detector (HPLC-FL) and the limit of detection and limit of quantitation were 0.06 and 0.6 μg/L, respectively. During the winemaking, the stages that show higher toxin reduction were drawn-off wine, after alcoholic fermentation and racking. Significant reductions in OTA levels were observed when winemaking was finished. A reduction of 92.6% was observed in wine made from grapes inoculated with ochratoxigenic fungi. Similar value (92%) was verified in wine made from grapes naturally contaminated with OTA. Considering all winemaking process, we may suggest that the decreasing of OTA levels was observed mainly due to adsorption of the toxin in cell wall of yeast. Furthermore, the adsorption of the toxin in suspended solids present in wine during the winemaking may be occurred.

Orientador: José Luiz Pereira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-21T13:27:50Z (GMT). No. of bitstreams: 1 Lopes_AlinedeSouza_M.pdf: 1681631 bytes, checksum: f77820cebe02c8058ad8b01cc2f36a6e (MD5) Previous issue date: 2012 / Resumo: O gênero Aspergillus é um grupo de fungos que possui diversas espécies produtoras de micotoxinas, distribuídas principalmente em três seções denominadas de Nigri, Flavi e Circumdati. Estudos para isolamento destas espécies estão sendo executados para se conhecer a micobiota e atuar na prevenção e redução da contaminação dos alimentos, principalmente por micotoxinas, como também são úteis nas descobertas de novas espécies. A identificação de fungos, como o gênero Aspergillus sp foi, por muito tempo,realizada através de suas características morfológicas, sendo hoje amparadas por técnicas como a Biologia Molecular, fisiologia e detecção de metabólitos específicos produzidos pelos microrganismos. Com este objetivo, este trabalho apresenta o inicio do levantamento de dados relacionado à ocorrência, caracteres morfológicos, fisiológicos,bioquímicos e moleculares, assim como a distribuição geográfica. A partir do isolamento de 10.048 cepas potencialmente toxigênicos de amostras de café, cacau, castanha do Brasil e frutas secas (tâmaras, uvas passas, figos e ameixas), matérias-primas de projetos desenvolvidos no Laboratório de Microbiologia do Instituto de Tecnologia de Alimentos (ITAL), 5.069 destes isolados foram preservadas em sílica gel, exigindo a catalogação dos dados. Neste acervo, a section Flavi predominou com o número de 2.507 culturas (32% destas cepas foram produtoras de aflatoxinas), seguida da section Nigri com 2.078 e 463 da section Circumdati que, somando, contribuiram com 11% de fungos produtores de ocratoxina A. Os Aspergillus da section Nigri apareceram em número considerável em todos os substratos, confirmando a sua predominância destes como contaminantes de alimentos. As amostras de castanha do Brasil contribuíram com o maior número de isolados, principalmente pela biodiversidade da floresta e colheita extrativista. Fungos que apresentaram estruturas diferenciadas, representantes de grupos com mesmas características, toxicidade ou espécies novas foram encaminhados para outros tipos de identificação. Duzentos e setenta e seis culturas foram identificadas por análise molecular, 435 pela extração de seus metabólitos e 87 espécies foram classificadas através da identificação polifásica. A distribuição das culturas apresentou representantes do Norte, Nordeste, Sul e Sudeste do Brasil, sendo que o Pará e Amazonas contribuíram com 2.759, como também culturas originárias de amostras de outros países como Irã,Turquia, Tunísia, EUA, México, Espanha e Argentina. A rotina de uma coleção consiste em novos isolamentos, manutenção do acervo e atualização do banco de dados, um trabalho enriquecedor para a ciência e que nunca se encerra / Abstract: The genus Aspergillus is part of a fungi group with several species that produce mycotoxins, mainly distributed in three sections named Nigri, Flavi and Circumdati. Studies to isolate these microorganism types are being made to know the mycobiota and their function in prevention and reduction of food contamination, mainly by mycotoxins and also to discover new species. The Aspergillus fungi identification was for a long time made by morphological characteristics but now it is supported by techniques such as molecular biology, physiology and detection of microorganism metabolites. With the objective this work presents the beginning of data collection related to the occurrence, morphological, physiological, biochemical and molecular, as well as the geographic distribution. From the potentially toxigenic strains isolation of 10,048 samples of coffee, cocoa, Brazil nuts and dried fruit (dates, raisins, figs and prunes) raw materials for projects developed in the Laboratory of Microbiology, Institute of Food Technology (ITAL), 5069 of these isolates were preserved in silica gel, requiring cataloging data. In this collection section Flavi predominates with 2,507 cultures (32% of these strains are aflatoxin producers) followed by section Nigri with 2,078 and 463 of section Circumdati that together, contributes 11% of ochratoxin A fungi producing. The Aspergillus section Nigri showed a considerable number of all substrates, confirming its predominance and resistance as a food contaminant. Brazil nut samples contributed with the largest number of strains due to forest biodiversity and harvest extraction. Fungi that had differentiated structures, group representatives with similar characteristics, toxicity or new species were referred to other types of identification. Two hundred and seventy six isolates were identified by molecular analysis with 435 metabolites, 88 species of Aspergillus showed the two forms, being classified by polyphasic identification. The genus Aspergillus was identified widely from countries such as Iran, Turkey, Tunisia, USA, Mexico, Spain and Argentina. In Brazil there are representatives from the North, Northeast, South and Southeast, and Para and Amazonas states that contributed to 2,759 cultures. The collection routine consists of new insolation, collection maintenance and updating of the database, which is an undending task for the enrichment of science / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos

Orientador : Lucia Maria Valente Soares / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T02:12:47Z (GMT). No. of bitstreams: 1 Mariutti_LilianReginaBarros_M.pdf: 1680960 bytes, checksum: 54a05df2fbb3674f6e787d861ae60c73 (MD5) Previous issue date: 2003 / Resumo: Um recente relato da presença de Aspergillus flavus e Aspergillus parasiticus em polpa de tomate industrializada brasileira motivou preocupações quanto a possível presença de micotoxinas em produtos de tomate nacionais. Aspergillus fIavus e Aspergillus parasiticus são conhecidos produtores de aflatoxinas, uma família de toxinas com propriedades hepatotóxicas, mutagênicas, teratogênicas e carcinogênicas. No presente trabalho foi adaptado e avaliado um método para determinação de aflatoxinas em produtos de tomate por cromatografia de camada delgada com detecção por comparação visual com padrões. Para verificar a possível contaminação de produtos de tomate comercializados com aflatoxinas foram analisadas 63 amostras de produtos de tomate (polpa, extrato, purê, catchup, tomate desidratado e tomate seco conservado em óleo) provenientes de 5 Estados e uma do exterior, compreendendo 29 marcas. A avaliação do método para determinação das aflatoxinas em produtos de tomate resultou em uma recuperação médía de 86%, para as quatro aflatoxinas, em dois níveis de adição. Os limites de detecção para as aflatoxinas B1, B2, G1 e G2 variaram entre 2 e 7 mg/Kg dependendo do tipo de produto. As aflatoxinas não foram detectadas em nenhuma das amostras analisadas / Abstract: A recent report on the presence of Aspergillus flavus and Aspergillus parasiticus in tomato pulp from a Brazilian plant caused concern about the possible presence of mycotoxins in tomato products from local plants. Aspergillus flavus and Aspergillus parasiticus are known producers of aflatoxins, a group of toxins with hepatotoxic, mutagenic, teratogenic, and carcinogenic properties. In the present work a thin layer chromatographic method with visual detection for the determination of aflatoxins in tomato products was adapted and evaluated. In order to verify a possible contamination of tomato products with aflatoxins, 63 samples of tomato products (pulp, paste, purée, catsup, dehydrated tomato and dried tomatoes in oil preserve) from 5 states and one from abroad, totaling 29 brands, were analyzed. The method evaluation showed an average recovery of 86%, for all four aflatoxins, at two levels of addition. The detection limits for the aflatoxins 81, 82, G1 e G2 ranged from 2 and 7 mg/Kg depending on the type of product. Aflatoxins were not detected in any of the samples analyzed. / Mestrado / Mestre em Ciência de Alimentos

M.Sc. (Nanoscience) / Ochratoxin A and Aflatoxin B1 are important food contaminates as they are known to be mutagenic, genotoxic, nephrotoxic, hepatotoxic, immunosuppressive and teratogenic to both animals and humans. These mycotoxins are associated with the contamination of food stuff such as grapes, maize, red pepper, meat, milk, beans and processed products from contaminated raw material. Current physical, biological and chemical methods employed to improve the safety of food often compromise the nutritional value and result in huge losses. The alternative to these treatments are addition of supplements with protective properties to reduce the toxicity of mycotoxins or prevent their formation. The work presented in this dissertation reports an attempt to develop such materials to prevent damage caused by ochratoxin A and aflatoxin B1. This was done through the synthesis; characterisation and cytotoxicity study of chitosan nanoparticles with methanolic plant extracts (L. leonurus, M. longifolia and A. montanus). Inhibition of cellular damage due to mycotoxins for possible application in prevention of cellular damage by mycotoxins also presented. Chitosan nanoparticles were synthesised using an ionic gelation method with sodium triphosphate as the cross linker. The methanolic medicinal plants extracts were incorporated into the chitosan solution before synthesising nanoparticles, and nanoparticle synthesis initiated by the addition of sodium triphosphate solution. The synthesised products were characterised using zetasizer, transmission electron microscopy, x-ray diffraction and Fourier-transform infrared spectroscopy. The extracts’ antioxidant ability was evaluated before incorporation into chitosan using 2, 2-diphenyl- 1-picrylhydrazy (DPPH) radical scavenging assay. This assay was performed using UVvis spectroscopy. The cytotoxicity of the synthesised nanoparticles was assessed using a Vero cell line and by evaluating the cell viability with an MTS assay. The nanoparticles were successfully synthesised and showed the presence of different functional groups as expected. Plain chitosan nanoparticles were roughly spherical shaped and had smooth surfaces, nanoparticles containing extracts similarly were spherical in shape as well but had rougher surfaces when visualised under TEM. All nanoparticles had positive zeta potentials between 26 – 28 mV. The average particle sizes ranged between 31 – 65 nm as measured using TEM and average particle sizes obtained using zetasiser was 78 – 190 nm. The cytotoxicity studies of plain nanoparticles and nanoparticles with extract showed that the synthesised nanomaterials were not toxic even at concentration of 500 μg/ml and less than 20% of the Vero cells were affected under these conditions.

D.Tech. (Biomedical technology) / The majority of the South African rural black population remain is exposed to HIV/ AIDS and other chronic diseases, tuberculosis, malaria and cancer. The effect of single and combined mycotoxins on their health and particularly their immune system is unknown and remain of concern as these populations are on daily basis exposed more than one mycotoxin at once. The aim of this study was to evaluate the exposure of South African rural black populations to mycotoxins via animal products in comparison to urban populations and to assess the effect of the major mycotoxins (fumonisin B1 (FB1), aflatoxin B1 (AFB1) and ochratoxin A (OTA)) mostly present in their food on human and animals (pigs) mononuclear cells and by extrapolation, evaluate possibilities of these mycotoxins on the immune system. To achieve this, animal feed and animal products (milk, serum, and tissues) obtained from selected rural and commercial farms in selected areas of South Africa were analysed for fungal and mycotoxins contamination. It was found in this study that almost all of the samples from both areas were contaminated with the major mycotoxin producing fungal strains (Fusarium, Aspergillus and Penicillium spp.) with the most prominent among them being Aspergillus flavus (87%), A. parasiticus (43%), A. niger (69%), A. ochraceus (42%), A. candidus (23%), F. verticillioides (98%) F. graminearum (67%) and P. Verrucosum (48.9%) and in commercial samples A. flavus (98%), A. parasiticus (51%), A. ochraceus (65%), A. niger (31%), A. candidus (21%), F. verticillioides (F. moniliforme) (68%), F. graminearum (43%) and P. verrucosum (7%). While, the three main mycotoxins were also present and contaminated most samples with fumonisins (FBs) 0in rural and commercial samples at 90.6% and 93.3% respectively with respective means values of 10136.4 ppb and 1045.4 ppb. Aflatoxins (AFs) contamination was of 92.0% in rural samples and 96.2% in commercial samples with means concentrations of 168.8 ppb and 294.1 ppb respectively. While 85.4% and 83.7% of rural and commercial samples respectively were contaminated with ochratoxin A (OTA), with mean concentrations of 67.6 ppb and 89.4 ppb respectively. Zearalenone (ZEA) concentrations were of 43.6 ppb in rural samples and 62.7 ppb in commercial samples with respective contamination of 50.6% and 55.3%. In addition, a co-occurrence of fungi and mycotoxins contaminations was found in both rural and commercial samples. It was found that, 50.5% of rural and 53% of commercial samples were contaminated with all four analyzed mycotoxins. (FBs, AFs, OTA and ZEA), whereas, 81.2% and 79.5% of samples respectively from rural and commercial farms were contaminated with FBs, AFs and OTA mycotoxins simultaneously. The above-obtained results are of significance in this study as they confirm the hypothesis of fungal contamination and mycotoxin co-occurrence in South African feed and their possible combined effects on consumers.

De nombreuses espèces de moisissures (Aspergillus, Fusarium, Penicillium…) produisent des molécules toxiques appelées mycotoxines. Malgré des efforts agronomiques croissants, la contamination en mycotoxines dans les produits agricoles est toujours présente. Des stratégies de décontamination sont alors utiles pour limiter l’impact des mycotoxines sur la santé animale ou humaine. La première stratégie que nous avons étudiée est le piégeage par adsorption de mycotoxines sur des spores d’Aspergillus de la section Nigri. Nous avons démontré que les spores vivantes sont aussi efficaces que les spores inactivées à la chaleur, indiquant que les composés responsables de l’adsorption ne sont pas altérés par ce traitement. Le phénomène d’adsorption semble être principalement du à des interactions hydrophobes. Des études restent à faire sur l’efficacité d’un tel procédé in vivo et pour caractériser les composés responsables. La deuxième stratégie étudiée a été la biotransformation d’une mycotoxine particulière, la zéaralénone. Plusieurs microorganismes ont été testés. Parmi eux, il a été démontré que certaines espèces d’Aspergillus avaient la capacité de transformer la zéaralénone en zéaralénone-sulfate. La toxicité de ce composé a été évaluée par test de prolifération de cellules cancéreuses MCF-7. Ces cellules ont la particularité de proliférer en présence de composés oestrogéniques. Il a été montré que la zéaralénone-sulfate provoquait peu de prolifération chez ces cellules, suggérant une toxicité plus faible que la zéaralénone. Des études seront effectuées pour évaluer la stabilité d’un tel conjugué in vivo. / Several species of fungi (Aspergillus, Fusarium, Penicillium…) are producers of very hazardous mycotoxins. Despite the use of recommended agricultural practices to avoid mold development and mycotoxinogenesis during crop growth, harvesting and storage, contamination by mycotoxins still occurs. Decontamination procedures are useful to reduce the mycotoxin content of contaminated raw materials. The first strategy we studied was to decrease the bioavailability of mycotoxins trapping them with binding agents. For the first time, the adsorption of mycotoxins by conidia of black Aspergilli has been demonstrated. Heat-treated conidia are as efficient as living conidia, which demonstrates that the components involved in adsorption are not affected by heat-treatment. The adsorption phenomenon seems to involved hydrophobic interactions. Further in vivo studies are necessary to develop the application of such a decontamination process to contaminated raw materials and feeds. The second strategy studied was the biodegradation of zearalenone by microorganisms which could offer a pratical and efficient method to alleviate negative effects on animals. For the first time, some Aspergillus niger strains, isolated from grapes, have been shown to transform zearalenone to zearalenone-sulfate. To be sure that zearalenone biotransformation leads to a detoxification, the estrogenic toxicity of zearalenone-sulfate was determined by cell culture studies. An estrogen receptor positive breast cancer cell line (MCF-7) was used to confirm the lost of toxicity by E-screen assay. The test principle is based on the fact that MCF-7 cells proliferate in presence of estrogenic substances. Zearalenone-sulfate was less estrogenic than zearalenone. Further work will focus on the stability of the zearalenone-sulfate in vivo.

Mycotoxins have become an important issue for the grain industry and animal producers with a growing interest in the decontamination and remediation of highly contaminated feedstuffs. Practical methods to detoxify mycotoxin-contaminated grain on a large scale and in a cost-effective manner are essential but not currently available. The most recent and promising approach to detoxify mycotoxin-contaminated grain is the use of non-nutritive adsorbents, which bind the aflatoxin and thereby reduce their absorption from the gastrointestinal tract. Humic acids are products of chemical and biological transformations of animal and plant residues and are widely distributed in nature. Humic acids have some therapeutic characteristics and a strong binding affinity for several compounds. A South African company developed an effective large-scale regeneration process for humic acids from coal, called oxihumate. This study evaluated the effectiveness of oxihumate to adsorb mycotoxins, for the purpose of developing it as a commercial mycotoxin binder to be used in the preventative management of contaminated poultry feedstuffs. The in vitro affinity and adsorption capacity of oxihumate to aflatoxin was evaluated and the efficacy of oxihumate as an aflatoxin binder in broiler feeds in vivo was determined. The data showed adsorptions of about 10.3, 7.4 and 11.9 mg aflatoxin B1/g oxihumate at pH 3, 5 and 7, respectively. Oxihumate adsorbed 1.2, 2.6 and 8.5 mg aflatoxin G2/g at pH 3, 5 and 7, respectively. Oxihumate supplementation at a concentration of 3.5 g/kg feed was effective in diminishing the growth inhibitory effects of aflatoxin and apparent protection was noted for some of the organ, haematological and serum biochemical changes associated with aflatoxicosis. These results suggest that oxihumate could alleviate some of the toxic effects of aflatoxin in growing broilers, and when used with other sound mycotoxin management practices, might prove beneficial in the preventative management of aflatoxin-contaminated feedstuffs for poultry. The improvement observed during this specific study was, however, not satisfactory enough to recommend oxihumate as a commercially available product. / Thesis (PhD (Animal and Wildlife Sciences))--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

Submitted in fulfillment of the requirements for the Degree of Master of Technology: Biological sciences at the ML Sultan Technikon, 2000. / Plant medicine is an important area of commercial activity in South Africa. This is a rapidly expanding market, thus we are evaluating natural and stressinduced compounds (phytoalexins) from plants as agents that may be able to control mycotoxins. Natural compounds from Bridelia micrantha, Warburgia salutaris, Lippia javanica and Scenecio serratuloides and stress-induced compounds (phytoalexins) from Citrus sinensis cv Valencia were screened for antitunqal and antimycotoxic activity by bioautography against a test organism (Cladosporium cladosporoides) and mycotoxin producing fungi (Fusarium moniliforme and Aspergillus flavus). / M

O objetivo deste trabalho foi estudar a transferência de aflatoxinas da ração para peixes lambari (Astyanax altiparanae), avaliando a influência dos níveis de toxina na ração sobre o desempenho dos peixes. As aflatoxinas foram incorporadas à ração extrusada para peixes tropicais, previamente testada para a presença de aflatoxinas, e as concentrações foram confirmadas por cromatografia líquida de alta eficiência (CLAE). Os tratamentos foram constituídos por: Controle - ração sem toxina; A. Ração + 10 µg AFB1/kg; B. Ração + 20 µg AFB1/kg e C. Ração + 50 µg AFB1/kg. Os juvenis de lambari foram alocados em aquários com densidade de 1 peixe por litro. O experimento foi realizado por 120 dias, com três repetições. A cada 30 dias foram realizados levantamentos biométricos e avaliação do desempenho (taxa de crescimento, sobrevivência, ganho de peso). A determinação de aflatoxinas nas amostras foi realizada por CLAE em músculo e fígado. Mensalmente, dez peixes por aquário foram utilizados para compor uma amostra, totalizando 48 amostras de músculo e 48 amostras de fígado analisadas ao final do experimento. As aflatoxinas na dieta prejudicaram o desempenho dos lambaris, observando-se menor peso e tamanho dos peixes nos tratamentos com aflatoxinas em relação ao controle. Houve também menor consumo de ração pelos peixes do tratamento C no período final do experimento. De modo geral, observou-se que, principalmente a partir dos 90 dias de experimento, houve acúmulo de aflatoxinas no fígado e no músculo dos animais. A concentração de aflatoxina B1 observada no músculo dos lambaris ao final do período de exposição foi semelhante aos níveis empregados na dieta. Os resultados mostraram que o lambari é uma espécie sensível, havendo efeito das aflatoxinas sobre o desempenho e acúmulo de aflatoxinas no músculo e fígado. Assim, quando da exposição diária e prolongada de lambaris às aflatoxinas, conclui-se que os limites atuais das legislações para aflatoxinas em ração animal não garantem segurança à produção e à saúde dos consumidores. / The aim of this study was to evaluate the transfer of aflatoxins from feed to lambari fish (Astyanax altiparanae), assessing the influence of toxin levels on fish performance. Aflatoxins were incorporated into extruded feed for tropical fish, previously tested for aflatoxins, and the concentrations were confirmed by high-performance liquid chromatography (HPLC). The treatments were: Control - feed without toxin; A. Feed + 10 µg AFB1/kg; B. Feed + 20 µg AFB1/kg and C. Feed + 50 µg AFB1/kg. Juveniles of lambari fish were placed in aquariums with density of 1 fish per liter. The experiment was conducted for 120 days, with three replications. Every 30 days biometric surveys were performed, including weight and standard length. Feed intake, feed conversion, growth rate and survival were also evaluated. Determination of aflatoxins was carried out by HPLC in muscle and liver. Monthly, a pool of 10 fish were used to make a sample, adding up to 48 samples of muscle and 48 samples of liver analyzed at the end of the experiment. Aflatoxins in the diet impaired the lambari performance, with lower weight and size of fish from aflatoxins treatments compared to control. There was also lower feed intake by fish from treatment C in the final period of the experiment. In general, it was observed that, mainly from 90 days of experiment, there was accumulation of aflatoxins in the liver of lambari fish and consequently in the muscle. Aflatoxin B1 concentration observed in the muscle of lambari fish at the end of the exposure period was similar to the levels used in the diet. Results showed that lambari fish is sensitive specie, with effects of aflatoxins on performance and accumulation of aflatoxins in muscle and liver. Therefore, when daily and prolonged exposure of lambaris to aflatoxins, it is concluded that the current regulation limits for aflatoxins in animal feed do not guarantee safety production and consumer health.

This master thesis deals with monitoring of a content of deoxynivalenol, its metabolite deoxynivalenol-3-b-D-glucopyranoside and ochratoxin A in beer samples collected from retail market in the Czech Republic, Poland and Slovakia. The theoretical part describes general characteristics of mycotoxins, its transfer from field barely through malt to beer and its occurrence in beers. Malting process and brewing technology were also mentioned. Subsequently possibilities for a determination of the mycotoxins by the chromatografic and immunochemical method were presented. The experimental section describes analysis of 30 samples of beer. The analyses were conducted using ultra high-performance liquid chromatography with fluorimetric detection (UPLC/FLR) for ochratoxin A and high-performance liquid chromatography coupled with mass spectrometer (HPLC/MS) for deoxynivalenol and its metabolite. Ochratoxin A was detected in 25 of the 30 samples in concentration range of 0,6 - 82,5 ng·l-1. Deoxynivalenol was found in 24 of the 30 samples with concentration range of 2,29 - 12,57 ug·l-1 and deoxynivalenol-3-b-D-glucopyranoside was occure in 19 of the 30 samples in concentration range of 2,45 - 12,47 ug·l-1. It was also assessed the relationship between beer gushing and presence of mycotoxins in beer. No connection between the parameters has been found. Consequently it is not possible to predict beer gushing from the presence of mycotoxins.