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Natural toxins in food and their effect on human health
Houdková, Kristine ; Bušová, Milena (advisor) ; Schlenker, Anna (referee)
This bachelor thesis deals with the occurrence of natural toxic substances in food and describes their effect on human health. It focuses on toxic substances that are a natural part of plants, animals, and also on natural contaminants. This work is divided into theoretical and practical part. The aim of this work is to provide information and raise awareness about these substances, because they are an integral part of most foods. The purpose of the practical part is find out the level of public awareness of toxins in food and discover the frequency of mycotoxins appearences in food from the Rapid Alert System for Food and Feed (RASFF), which operates within the European Union. Mold toxins are a major worldwide problem, both in terms of public health and global economic. The research part of the work was carried out using a questionnaire survey through social networks. The general public seems to have a basic awareness of food safety and toxins substances in food. The bachelor thesis can serve as an informative and educational material for the public. Key words natural toxins - toxic substances - mycotoxins - alkaloids - poison
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The determination of mycotoxins in commercial beers
Martiník, Jan ; Benešová,, Karolína (referee) ; Mgr. Marek Pernica, Ph.D (advisor)
Mycotoxins are secondary metabolites of microscopic fibrous micromycetes that are able to infect cereals. The use of contaminated materials can lead to transfer of mycotoxins into the final product, such as beer. The master’s thesis deals with the determination of mycotoxins in beers. The theoretical part of this thesis describes selected mycotoxins, their occurrence, toxic properties and legislative limits of the European Union. The theoretical part also deals with the description of beer production and the possibilities of mycotoxin determination. The theoretical part also describes the statistical methods used for data processing. The experimental part of this work describes the validation of the method for determination of mycotoxins in beers. This section also describes the optimization of mycotoxin extraction using a commercially available 11+Myco MS-PREP® immunoaffinity column. The conditions for the determination of mycotoxins on UPLC-MS/MS are given in this thesis. The validation parameters such as linearity, accuracy, precision, LOD and LOQ were determined. This section contains a description of beer samples used for the determination of mycotoxins. The goal of the thesis was to optimize and validate the method for determination of mycotoxins in beers. From the validation parameters, it was found that this method is suitable for its intended purpose, namely for mycotoxins aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, fumonisin B1, fumonisin B2, fumonisin B3, ochratoxin A, ochratoxin B, zearalenone, -zearalenol, -zearalenol, -zearalanol, -zearalanol, deoxynivalenol, 3-acetyldeoxynivalenol, T-2 toxin and HT-2 toxin. The recoveries of this method ranged from 72,2 % to 100,0 %. The validated method was used for determination of above-mentioned mycotoxins in 89 beers. Of the total number of beers, 37 were produced in the Czech Republic and 52 in other European countries. Mycotoxins deoxynivalenol, T-2 toxin and HT-2 toxin were found in all beer samples. Common mycotoxins included fumonisin B1, ochratoxin A, -zearalenol and 3-acetyldeoxynivalenol. The mycotoxins aflatoxin B1, aflatoxin B2, aflatoxin G1, fumonisin B2, fumonisin B3, zearalenone and ochratoxin B were identified in less than 50 % of the samples. Mycotoxins aflatoxin G2, -zearalenol, -zearalanol and -zearalanol were not determined in any tested samples. The results of the analysis were subjected to statistical processing where the concentrations determined in Czech and European beers were compared. Principal component analysis and correlation analysis were created for aflatoxin B1, fumonisins, ochratoxin A, -zearalenol, deoxynivalenol, 3-acetlydeoxynivalenol, T-2 toxin and HT-2 toxin. The results of the analysis were compared with published studies.
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Mycotoxins in fermented beverages
Martiník, Jan ; Svoboda, Zdeněk (referee) ; Běláková,, Sylvie (advisor)
Mycotoxins are toxic secondary metabolites of mold and fungi that attack cereals, wine grapes or apples, which are then used to produce fermented beverages. This thesis focuses on mycotoxin patulin which is primarily found in ciders. The theoretical part describes selected mycotoxins, legislation concerning these mycotoxins and their occurrence in fermented beverages. Section of the theoretical part is also dedicated to the description of fermented beverages and analytical methods used to determine mycotoxins in beverages. The experimental part deals with the validation parameters of the method for determination of patulin and 5-HMF. It also deals with the extraction and determination of these substances. Columns EASIMIPTM PATULIN were used in the extraction of patulin and 5-HMF and the concentration was measured by ultra high performance chromatography with photodiode array detection (UPLC/PDA). The determination of patulin and 5-HMF was performed in a total of 33 samples of cider, 9 samples of apple juice, 2 samples of wine and 2 samples of radler. Patulin was found in 6,1 % of cider samples and in 44,4 % of apple juice samples. 5-HMF was found in both wines and radlers, in 78,8 % of ciders and in 77,8 % of apple juices. All measurement data is processed in the results and discussion. The results were compared with foreign studies.
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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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Stability of selected mycotoxins in beer
Štáblová, Taťána ; Benešová, Karolína (referee) ; Běláková, Sylvie (advisor)
Mycotoxins are secondary metabolites of moulds, which attack cereals, for example barley, from which mycotoxins then get to beer. This submitted work is focused on ochratoxin A, deoxynivalenol and zearalenone, which can occur in beer. The first part of this master’s thesis consists of literary research, which describes mycotoxins in general, points out their occurrence, prevention of their formation and delivers information about their physical and chemical properties and toxicity. Furthermore, the research contains basis of malt and beer technology, the occurrence of mycotoxins in beer and raw materials for its production. The research describes changes in concentration of mycotoxins across malt and beer production. The next part deals with possibilities of determination of mycotoxins in barley, malt and beer, compares individual methods of their determination and points out many difficulties of some analyses. The experimental part of this work pursues determination of ochratoxin A, deoxynivalenol and zearalenone in different types of beer with the help of UPLC-FLR, HPLC-MS and ELISA. Instrumental techniques are validated and gathered results are compared with the results in literature. The goal of this master’s thesis is to assess the stability of ochratoxin A and deoxynivalenol in beer over time. The gained results show that there are changes in the concentration of ochratoxin A over time, nevertheless those changes show no pattern. Overall, there was a decrease in concentration in 47 % of the samples and an increase in 28 % of them. In the rest of the samples the concentration did not change. The concentration of deoxynivalenol does not change over time. One of the other goals of this thesis is monitoring of selected mycotoxins in beer. The average concentration of ochratoxin A in the samples was 39 ng/l and deoxynivalenol 9,9 g/l. Zearalenone did not occur in any of the samples when determined by liquid chromatography. All results agree with literature. Next, the thesis compares different analytical methods for determination of ochratoxin A, deoxynivalenol and zearalenone. The screening method ELISA is compared to UPLC-FLR and HPLC-MS. The determination of ochratoxin A by ELISA has shown to be time consuming, nevertheless the results responded to instrumental technique. ELISA overestimated the results of determination of deoxynivalenol in beer by 363–697 % and with zearalenone there were found false positive results.
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Toxic substances in food and their effects to human health
KADLECOVÁ, Hana
The bachelor thesis "Toxic substances and their effects to human health" deals with characteristics of selected historical periods of toxicology. It describes the basic concepts of toxicology. It briefly characterizes toxic substances of plant and animal origin. More attention is paid to mycotoxins, especially aflatoxins, fumonisins, ochratoxins and zearaleon. A very important part of this thesis is the prevention of the effects of toxic substances on human health and describes the partial measures that are necessary before consumption or preparing of food. The practical part examines the awareness of university students about important toxic substances in food. It assesses whether these students recognize the desired mold species on food. Next it is interested in what precautionary measures are taken by university students before consuming and preparing food. The conclusion of the thesis shows that the know-how of university students is relatively high.
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The Usage of Plasma Technologies to Improve the Quality of Feedstuffs
HAVELKA, Zbyněk
The dissertation thesis deals with the problems of the use of plasma technologies in agriculture for the purpose of improving the quality of feedstuffs for agricultural animals. The attention is focused above all on the use of low-temperature gliding arc plasma discharge generated by the atmospheric pressure for the elimination of model fungal pathogens (T. virens) and for the testing of the possibility of the use of plasma for the decreasing of mycotoxin load (DON and D3G). The professional orientation of the dissertation thesis is strongly interdisciplinary with the overlap to the area of the physics of plasma, microbiology, zootechnics and the proposal and construction of technical facilities. With that corresponds also the division of thesis into individual chapters. In the research part, there is a summary of actual pieces of knowledge from the area of fungal microorganisms and mycotoxins produced by these with the view on their presence in feedstuffs. There follows a research of pieces of knowledge of low-temperature plasma and its applications in the food industry and feeding. In the chapter Material and Methodology, the applicated methods of work, employed instruments and biological material are described. The resulting part is, for its clear arrangement, divided into five subchapters ? stating of selected parameters of plasma device, influence of plasma on nutritional parameters, influence of plasma on the model fungus Trichoderma virens and possibilities of the use of plasma discharge for the decreasing of concentration of mycotoxins in feedstuffs. The final part is dedicated to the description of system which enables the treatment of samples in continuous regime. The treatment of mycelial discs by plasma discharge lead to the decrease of germination capacity of spores of fungi, while there was experimentally proven the synergic effect of the influence of individual mechanisms by which the plasma interacts with the surface of biological material. At the same time, there was not observed a more significant change in the composition of feedstuffs, more significant is only the change of humidity of sample. In the laboratory conditions, the decreasing of concentration of mycotoxins spread on laboratory glass was proven. At the samples of feedstuffs contaminated by natural way, it was not successful to reliably provedecreasing of concentration of mycotoxins in a sample as a result of plasma activity.
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Chemical contaminants in milk
UHLÍKOVÁ, Tereza
The bachelor thesis is focused on the issue of contaminants in milk, such as pesticides, veterinary drugs, heavy metals, mycotoxins and their influence on milk quality. These substances present in milk have a negative impact on consumers health and for dairy cows health. The presence of contaminants in milk should therefore be monitored mainly to ensure the safe of the milk. An important group in terms of milk contamination are veterinary drugs. Their residues have a negative impact for milk processing and consumer health, but can also contribute to an increase in antimicrobial resistance. However, over-limit findings of veterinary drug residues in the Czech Republic have been on a low level in recent years. Special attention has been paid to milk contamination with mycotoxins because this problem is currently a very topical and discussed topic. Most of the work is focused on the contamination of milk with aflatoxin M1, which is the most explored milk-related mycotoxin.
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