|
|
Posouzení vlivu země původu a způsobu zpracování na mikrobiotu vybraného koření
Menoušková, Karolína
The diploma thesis deals with the requirements for the quality of spices. It mainly deals with the microbial contamination of spices, factors of influence and possible means to prevent its contamination. Furthermore, the work deals with the characteristics of spices of the genus Capsicum, its range and possible use. In the practical part of the work, the microbial contamination of spices in peppers and chilli was determined. Individual spice samples differed depending on the country of origin, the method of technological processing, physical treatment and the content of capsaicin. During the microbiological analysis, the total number of microorganisms (CPM), the numbers of coliform bacteria and Escherichia coli, moulds and yeast, or the presence of Clostridum perfringens were monitored. The highest CPM value (4,49 log KTJ·g−1) was detected in the sample of ground chilli from China. A higher number of coliform bacteria and E. coli (2,49 log KTJ·g−1) was observed in the sample of sweet pepper from Spain. A significantly higher number of moulds and yeasts (3,13 log KTJ·g−1) was recorded in the sample of ground goulash pepper from the Czech Republic. In the case of Cl. perfringens, the presence of this bacterium was showed in 3 of 13 pepper and chilli spice samples. During the laboratory experiment, no significant deviations of occurrence of the monitored microorganisms were detected in comparison with the recommended limits or the results of scientific studies. The results show that microbial contamination may be affected by the country of origin, the physical treatment, or the alkaloid content of capsaicin, which evidences an antimicrobial activity. When monitoring the effect of technological processing on the spice microbiota, there was no statistically significant difference between the monitored pepper samples (P < 0,05).
|
|
|
Microbial contamination of raw food and cereal products
VENGLOVIČOVÁ, Kristýna
Plasma has been increasingly used in recent years due to its lethal effect on microorganisms. Foods treated in this way are not a risk to humans in terms of chemical substance. The literature search is focused on raw foods. Description of pathogenic microorganisms frequently occurring on seeds and methods of disposal feasible in accordance with the rules of the raw diet. The aim of this bachelor thesis was to evaluate the effect of low-temperature plasma on seeds. Seed groups were exposed to plasma for 4, 5, 6, 7 and 8 minutes. Seeds of mung beans, broccoli, watercress, radish and barley were treated with the plasma generated in the vacuum chamber. First of all was evaluated the inhibitory effect of plasma treatment on microorganisms occurring on seeds. Furthermore was monitored the impact on the growth of sprouts and roots. Could not be demonstrated the inhibitory effect of plasma on microorganisms present on seeds. The treated seeds compared to the untreated control group were contaminated with a similar amount of microorganisms. The effect on seed development was different for each species.
|
|
|
Natural enemies of the European spruce bark beetle \kur{Ips typographus}
BÁRTA, Jiří
Bark beetles (Scolitynae) are among the most important pests of forest stands, where they cause extensive damage, especially in spruce monocultures. Their negative effect is to attack the host tree, which is its source of food and at the same time provides them with space for reproduction. The bark beetle is able to have several generations per year under suitable temperature conditions. One of the most widespread is consi-dered to be the European spruce bark beetle Ips typographus. This species is able to search for weakened and abiotically damaged trees. Integrated Pest Management of forests includes several effective methods against bark beetles. The most used met-hods include the installation of feromone traps, traps trees and poisoned tripods. The European spruce bark beetle is in their population regulated by many natural enemies. From parasitoids such as Coeloides bostrichorum and Rhopalicus tutela and predators Thanasimus formicarius and Medetera spp. to pathogenic microorganisms such as entomopathogenic viruses, bacteria, protozoa, microsporidia and especially entomo-pathogenic fungi belonging to the order Hypocreales. The most important species is the fungus Beauveria bassiana, which has the greatest potential in the biological pro-tection of spruce stands.
|
|
|
Factors affecting quality of raw cow´s milk during milking and storage at farm
HAVRÁNKOVÁ, Iveta
Milk is one of the few products which we can use for direct consumption. Not only is it important for human nutrition as a raw product, but it also finds an increasing usage in food industry. The quality of milk is affected by various factors. This work deals only with the most important ones, which have an influence on the nutrition value as well as on the microbiological and hygienic quality of milk.
|
guest ::
