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Aflatoxins in food and their influence on DNA and cell lines
Šislerová, Lucie ; Pernicová, Iva (referee) ; Brázda, Václav (advisor)
Aflatoxins present a great danger due to their high toxicity and carcinogenicity, which is not easily avoided in everyday life. Intoxication with aflatoxins causes a wide range of diseases ranging from mild diseases to organs necrosis or death. Aflatoxins mostly affect the liver, where it degrades and the formation of subsequent metabolites, which are the most toxic to the body. For this reason, their precise determination and understanding of the principle of their effect is very important. In this work, methods for monitoring and closer determination of aflatoxin effects on human cells were calibrated. The methods that were used are: MTT viability assays, fluorescence microscopy and flow cytometry. Next, the amount of aflatoxins present in different foods with different storage conditions was measured. For this analysis were used ELISA assays RIDASCREEN Aflatoxin Total and RIDA Aflatoxin column. Calibrated methods were compared with the methods already used to determine the effect of aflatoxins and the results of the ELISA tests were compared with the limits of aflatoxin levels permitted by the Czech legislation. None of the controlled foods contained above-the-limit concentration of aflatoxins, which in the Czech Republic is set at 4-10 µg/l (varies for different types of food). Foods that were poorly stored but not visibly affected by fungi showed the highest levels of aflatoxins. The LD50 value for aflatoxin B1 was determined to 12,25 µM. The type of cell death caused by aflatoxins was determined by flow cytometry and these data were further confirmed by fluorescence microscopy images.
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The evaluation of mycotoxins monitoring in selected raw materials
DYKOVÁ, Jitka
Contaminants in feed and food pose a long-term global issue that requires constant attention. The diploma thesis aimed to assess results of the monitoring of mycotoxin presence in feed, raw milk, and tissue of animals in the period 2015-2019 (from State Veterinary Administration of the Czech Republic), and further to evaluate notifications of danger in the period 2016-2019 in selected countries (from the Rapid Alert System for Food and Feed, RASFF). From the total of 1320 analysed feed samples during the period, there were 378 samples (28.6%) positive in mycotoxins. The highest presence was found for deoxynivalenol (143; 43.3%), on the contrary, the lowest number of positive samples was in aflatoxin B1 (25; 7.6%). From the total of 210 raw milk samples, only one positive sample was found, and it was even under the allowed hygiene limit, 0.05 ?g/kg. All liver tissue samples (n=130) were also in compliance with the hygiene limits. The total number of notifications during the evaluated period was 315 (2.2% in the EU). An alert which is the most serious type of notification presented 31% of total notifications. The alerts were caused mainly by the presence of Salmonellaspp. in poultry meat. The highest number of notifications were found in Germany (11.9% in the EU), the lowest number was reported in Slovakia (1.1% in the EU). Although the results of this thesis are very satisfactory, continuing regular contaminants monitoring is necessary to ensure food safety.
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Detection and identification of aflatoxins by means of portable liquid chromatograph for purpose of control of biological weapons prohibition
Šesták, Jozef ; Lunerová, K.
Method describes screening detection and identification of selected mycotoxins aflatoxins (aflatoxins B1, B2, G1 and G2), ochratoxins A, B and zearalenon by means of portable miniaturzed capillary liquid chromatograph (miniLC) with UV/VIS and fluorescence detector (FLD). The aim of the method is to provide rapid screening method for finding/excluding the presence of given mycotoxins in unknown samples. In case of positive finding, it is necessary to perform confirmation analysis using other instrumental methods (e. g. LC-MS). The method is intended namely for the needs of technical support of the State Office for Nuclear Safety for control and supervising activities in field of execution of the Act No. 281/1997 Coll (Biological Act).
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Aflatoxins in food and their influence on DNA and cell lines
Šislerová, Lucie ; Pernicová, Iva (referee) ; Brázda, Václav (advisor)
Aflatoxins present a great danger due to their high toxicity and carcinogenicity, which is not easily avoided in everyday life. Intoxication with aflatoxins causes a wide range of diseases ranging from mild diseases to organs necrosis or death. Aflatoxins mostly affect the liver, where it degrades and the formation of subsequent metabolites, which are the most toxic to the body. For this reason, their precise determination and understanding of the principle of their effect is very important. In this work, methods for monitoring and closer determination of aflatoxin effects on human cells were calibrated. The methods that were used are: MTT viability assays, fluorescence microscopy and flow cytometry. Next, the amount of aflatoxins present in different foods with different storage conditions was measured. For this analysis were used ELISA assays RIDASCREEN Aflatoxin Total and RIDA Aflatoxin column. Calibrated methods were compared with the methods already used to determine the effect of aflatoxins and the results of the ELISA tests were compared with the limits of aflatoxin levels permitted by the Czech legislation. None of the controlled foods contained above-the-limit concentration of aflatoxins, which in the Czech Republic is set at 4-10 µg/l (varies for different types of food). Foods that were poorly stored but not visibly affected by fungi showed the highest levels of aflatoxins. The LD50 value for aflatoxin B1 was determined to 12,25 µM. The type of cell death caused by aflatoxins was determined by flow cytometry and these data were further confirmed by fluorescence microscopy images.
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Occurrence of mycotoxins in milk and dairy products
DYKOVÁ, Jitka
The aim of the bachelor thesis was to create a literary review focused on microscopic filamentous fungi (micromycetes) and the occurrence of their secondary metabolites, mycotoxins, in milk and dairy products. The first part of the work dealt with a general characteristic of micromycetes, their positive and negative effects, and with the description of three main genera - Aspergillus, Penicillium and Fusarium. The next part of the work was focused on the occurrence of mycotoxins in milk and in dairy products. The ways of contamination were described, and also the most common mycotoxins in milk and in dairy products, mainly in cheese, and some preventive measures for their elimination.
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