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Zavedení metody lyofilizace probiotických kultur pro výzkumné účely
Drábková, Monika
The experimental part of this thesis focuses on monitoring the viability and stability of lyo-philized probiotic cultures during storage (at 4 °C, -20 °C). Further it deals with the compa-rison of the influence of selected protective substances of these bacteria on the survival of the lyophilization process. The assessment of the number of viable bacteria was carried out using cultivation methods at 5, 10 and 20 days. The results showed that the application of cryoprotectants improved the viability of probiotic bacteria, not only during the lyophili-zation process but also during the storage period. At the same time, an increasing trend with increasing storage time was observed. Comparing the effect of storage temperature on the viability of probiotics, it was found that L. acidophilus showed a higher tendency to survive at -20 °C in the sample without cryoprotectants. In contrary, the culture with sucrose tended to perform better at 4 °C. The other cultures did not show a statistically significant differen-ce (p < 0.05). In the case of L. rhamnosus, there was no statistically significant difference (p > 0.05) in any of the samples, so it can be said that storage temperature did not affect the viability of this bacterium. Overall, skim milk showed the best protective effect, followed by sucrose and lactose.
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Změny mikrobiologických a senzorických parametrů v průběhu skladování jogurtů
Bašková, Barbora
The diploma thesis entitled "Changes in microbiological and sensory parameters during storage of yoghurts" deals with the production, microbiological and sensor quality of yoghurts from cow's milk. The theoretical part is focused mainly on the issues of production and microbial contamination of yoghurts, including sensory defects. The practical part deals with the determination and evaluation of selected groups of microorganisms throughout the minimum shelf life of strawberry and white yogurt. The work also deals with sensory evaluation of yogurts at the beginning and end of the minimum shelf life. The results showed that both types of yogurt maintain microbiological and sensory quality throughout their minimum shelf life.
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Mikrobiologie snídaňových směsí a lyofilizovaného ovoce
Collinsová, Ria
The diploma thesis "Microbiology of breakfast cereals and lyophilized fruit" considers microorganisms and their occurrence in lyophilized fruit and in raw materials that are used to produce breakfast cereals. It focuses on the production, composition and storage options of breakfast cereals and lyophilized fruit. The thesis is focused on fruit lyophilization and the benefits of this method, compared to the classic heat drying. The practical part is focused on the microbiological analysis of selected products of breakfast cereals and lyophilized fruit. Samples were analyzed for the total number of microorganisms, fungi, yeast, coliform bacteria, and Escherichia coli. Finally, it was determined whether the microbiological limits set according to the norm. From the obtained results, it is clear, that higher number of MOs was evident in the sliced lyophilized fruit and in the chocolate-containing breakfast cereals. The results also show that the microbiological limit was not exceeded in the selected samples.
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Změny mikrobiologické jakosti ochucených olivových olejů v průběhu skladování
Soumarová, Tereza
This diploma thesis deals with the change of microbiological quality of flavoured olive oils during storage. The theoretical part is focused on the production composition of olive oil and its beneficial effects on health. It describes the optimal storage conditions for olive oils and the microbial quality which can be affected by the type of flavouring. In the practical part the work deals with microbiological analysis of flavoured olive oils. Olive oils were flavoured with various variants of rosemary and garlic (fresh, dried, essential oil). The microbiological analysis was carried out during annual storage and total numbers of microorganisms, the presence of anaerobic sporulates, yeasts and moulds, bacteria of the family Enterobacteriaceae, lactic acid bacteria and the occurren-ce of Salmonella spp. and Clostridium botulinum were measured. Only total numbers of microorganisms, anaerobic sporulates, bacteria of the family Enterobacteriaceae and yeasts and moulds were detected in the oils during storage. The results clearly show that flavouring with garlic, especially fresh garlic is more suitable type of olive oil flavouring than rosemary. There were no significant changes in the number of microorganisms during storage, however the presence of Enterobacter cloacea and aerogenes was detected.
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Mikrobiologické parametry bezlepkového cukrářského provozu
Poláčková, Gabriela
This diploma thesis concerns microbial contamination, which is a substantial factor in production, manufacture and distribution of confectionery products. The work describes types of contamination, types of pathogens and their subsequent impact on human health, focusing on gluten-free confectionery products in particular. It also deals with the prevention of microbial contamination. In order to experimentally verify the above findings, a microbiological screening of a selected gluten-free confectionery was carried out. Firstly, control smears of work surfaces and cooling equipment were taken. In addition, an air purity check was executed. Lastly, a key microbiological analysis of three different types of gluten-free confectionery products from selected confectionery was performed. The desserts were analyzed at the same temperatures, but at different time periods. From the results obtained, it can be stated that the selected confectionery and its products are in accordance with legislative regulations.
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Vliv teploty a doby skladování na mikrobiologickou kvalitu balené salátové zeleniny
Krejčová, Veronika
The diploma thesis deals with the issue of microbial safety of fresh salad vegetables. The number of microorganisms (increase/decrease) in fresh salad vegetable products was evaluated with respect to the effect of storage temperature and storage time. Single-species vegetables (baby spinach and cornsalad) and multi-species vegetables (mixes of leafy and salad vegetables) were chosen for the experiments. The following microbial indicators were monitored: total number of microorganisms, enterobacteria, coliform bacteria, Escherichia coli, Escherichia coli O157, Salmonella spp., yeasts and fungi. Samples of fresh salad vegetables were analyzed during storage on the 1st, 4th and 8th day after packaging. The numbers of microorganisms depending on the type of vegetable and contents of the package varied with storage time and storage temperature (temperature regimes 4°C and 7°C). An increase (P < 0.05) in the total number of microorganisms and enterobacteria was recorded between the 1st and 8th day of storage in the fresh salad vegetable mix 1 (sample C). In other cases, such as baby spinach (sample A), there was a noticeable increase (P < 0.05) in the total number of microorganisms between the 1st and 4th day of storage with no further change (P > 0.05) on 8th day. A decrease in coliform bacteria determined at the 2nd and 3rd sampling (P < 0.05) was recorded in the cornsalad (sample B). In most cases, there was no statistically significant difference in the growth (P > 0.05) of the microorganisms between the samples stored in different temperature regimes.
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Mikrobiální kontaminace piva v průběhu skladování
Zemánek, Zbyněk
This thesis pushes ahead the microbiological contamination of beer during storage. The theoretical part deals with the beer racking to different packaging materials and beer storage. It describes microorganisms which bring on beer contamination. For example Lactic acid bacteria, Wild yeast or molds are included there. Further it focuses on methods to eliminate these microorganisms. The experimental part deals with microbiological analysis of beer from different breweries during four months of storage. The samples are taken from Czech Republic sales network or straightly from brewery shortly after racking. Influences of producers, used packaging materials and storage are statically evaluated time according to measured values.
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Konstrukce a zprovoznění laboratorního UASB reaktoru
Pavlík, Jan
This diploma thesis deals in its first part with research on anaerobic reactors, their use and its advantages and disadvantages. The second part deals with the design, construction and operation of the UASB reactor in the laboratory. The work describes in detail the course of the experiment and the operation of the reactor in laboratory conditions.
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Změny mikrobiologických a vybraných kvalitativních parametrů konzumního mléka
Říha, Patrik
The diploma thesis deals with the microbiology of drinking milk. The theoretical part deals with the importance of milk in human nutrition, composition, microbiology of raw and heat-treated milk, heat treatment, important groups of microorganisms contaminating milk, pathogens of milk and milk treatment after milking. The experimental part of the work deals with the determination of selected groups of microorganisms - total number of microorganisms, coliform bacteria, enterococci, psychrotrophic microorganisms, lactic acid bacteria, E. coli, fungi, yeast and chemical analysis of milk, where the values of fat, protein, lactose, fat-free dry matter, dry matter, density, added water, freezing point and active and titratable acidity are determined in six milk samples.
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Mikroskopické houby jako kontaminanty raw tyčinek
Vávra, Jaroslav
The diploma thesis Microfungi as contaminants of raw sticks includes a theoretical and experimental part. The theoretical part is a literary research, which aims to get acquainted with raw foods, consumers of raw foods and their beliefs in connection with raw foods. Furthermore, the literary research deals with legislative regulations, production technology and summarizes potentially occurring genera of microscopic fungi. The experimental part then deals with the analysis of commercially available raw bars from several manufacturers, determines the total number of microorganisms, fungi and yeasts and compares individual products and brands. Although many microbes were found in some sticks, the legislation did not exceed the regulations.
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