A metabenztiazuron fotokémiai bomlása különböző adalékanyagok jelenlétében

A növényvédő szerek a talajban számos abiotikus és biotikus átalakulási folya-maton mehetnek keresztül. A talajt alkotó anyagok hatását különböző adalékanya-gokkal lehet modellezni. Kutatásunk során titán-dioxidot, agyagásványt, humusz-anyagokat, és benzofenont – töltésátviteli komplex kialakítására – használtunk erre a célra. A kutatás célja az volt, hogy felmérje a metabenztiazuron (MBTA) termé-szetes körülmények között lehetséges bomlási útvonalait. A herbicid molekula és a benzofenon között kialakult töltésátviteli komplextől azt vártuk, hogy az energia transzfer hatékonyabbá tételével segítse a bomlást. A kísérletünk eredményei igazolták ezt a várakozást, mivel a metabenztiazuron bomlása a benzofenon jelenlétében volt a leggyorsabb. A huminsav eredő hatása a bomlás enyhe gátlása volt. A titán-dioxid és a montmorillonit kis mértékben növelte a metabenztiazuron fotokémiai bomlásának sebességét, de a titán-dioxid esetében ez nem tekinthető jelentős hatásnak

Rapid detection of Listeria monocytogenes in raw milk and soft cheese by a redox potential measurement based method combined with real-time PCR

The incidence of outbreaks of foodborne listeriosis has indicated the need for a reliable and rapid detection of the microbe in different foodstuffs. A method combining redox potential measurement and real-time polymerase chain reaction (PCR) was developed to detect Listeria monocytogenes in artificially contaminated raw milk and soft cheese. Food samples of 25 g or 25 ml were homogenised in 225 ml of Listeria Enrichment Broth (LEB) with Oxford supplement, and the redox potential measurement technique was applied. For Listeria species the measuring time was maximum 34 h. The absence of L. monocytogenes could reliably be proven by the redox potential measurement method, but Listeria innocua and Bacillus subtilis could not be differentiated from L. monocytogenes on the basis of the redox curves. The presence of L. monocytogenes had to be confirmed by real-time PCR. The combination of these two methods proved to detect < 10 cfu/g of L. monocytogenes in a cost- and time-effective manner. This method can potentially be used as an alternative to the standard nutrient method for the rapid detection of L. monocytogenes in food

Effects of cephalexin residues on the starter culture's microbial activity during the fresh cheese making process

The aim of our study was to investigate the carry-over of cephalexin from cow’s milk to cheese and whey, as well as, to study the potential impact of its presence on the microbial activity of the starter culture. Before cheese-making, the raw milk was artificially contaminated to different antibiotic levels. Cephalexin concentrations and the pH values were measured all along the process. It was found that cephalexin was transferred less into the cheese curd (1.8-4.3 % of the original amount) than into the whey (29.3-42.8 %). According to the results the concentration of cephalexin did not influence substantially the pH changes during curding nor the activity of the starter culture. However, pH of the fresh cheese showed significant (p < 0.05) differences compared to the control suggesting that antibiotic residues even below MRL level may influence the quality of product

Farm to table: Residues of different pesticides in tomato and tomato juice – Food safety aspects

During plant cultivation, the pesticides can get into the tissue of vegetables due to crop protection processes, and thus into the food chain. Therefore, they constitute a potential risk to the consumer's health. Depletion of pesticides [spirotetramat (Movento), azoxystrobin and difenoconazole (Amistar Top)] was monitored by testing tomatoes treated individually or simultaneously and tomato juices prepared from the treated tomatoes. The investigations aimed to reveal any kinetic interaction between the compounds tested and changes in their elimination, and thus to assess their compliance with the official Maximum Residue Limits (MRLs). The co-presence of pesticides prolonged the elimination of the individual compounds which reached significantly higher residue levels ( P < 0.0001) in tomato, especially difenoconazole (45%) and azoxystrobin (50%) on day 8 after treatment that can cause food safety issues to the human consumers. However, the concentrations of pesticides applied alone or simultaneously were found to be below the corresponding MRL values after the withdrawal period in all investigated tomato and tomato juice samples. Accordingly, the investigated pesticides can be safely used simultaneously, their concentrations are in compliance with the legal regulations and thus their concomitant presence does not pose any risk to the consumers' health

Rapid in-house detection method of Campylobacter spp. from food by redox potential monitoring combined with real-time PCR

The rapid detection of Campylobacter spp. is of utmost importance for the reduction of infections in humans by contaminated food products. The standard culturing method (ISO 10272-1:2006) involves a high time and labour demand. In this paper, we present a method that reduces the detection time of Campylobacter spp. to or below one third as compared to the ISO method, at a reduced cost per test. We used redox potential change of enrichment cultures (Bolton broth with Bolton selective supplement) for reliably selecting Campylobacter-contaminated raw milk and broiler meat samples. Identification of Campylobacter spp. in the contaminated samples was done by real-time PCR method. Culturing time to conclusive redox monitoring varied between 6 and 24 h for positive samples, depending on the contamination rate, in contrast to 136 h with the standard culturing process. However, now the Campylobacter-negative majority of food samples will not need to be tested by real-time PCR because redox potential monitoring can identify them in the selective enrichment phase. This method could be potentially used as a faster alternative to the current standard ISO 10272-1:2006, for nonregulatory monitoring purposes

Az új algoritmusok és kódolási eljárások alkalmazása a mobil hírközlésben és informatikában = Application of new algorithms and coding procedures in mobile communications and computing

A kutatási munka során az alábbi résztémákban értünk el eredményeket: - mobil IP, - all IP hálózatok, - útkeresési algoritmusok, - hívásátadási algoritmusok, - mobil technológiák együttműködése, - a szolgáltatás minősége (QoS), - a mobil és informatikai hálózatok és rendszerek biztonsági kérdései, - több-felhasználós vétel, - kódosztásos többszörös hozzáférés, - forgalmi modellezés, - kódkonstrukció kódosztásos technológiákhoz, - kvantum számítástechnikai eljárások, - gráfelmélet, - kombinatorikus optimalizálás. A fenti szakterületeken végzett kutatásaink eredményei közül azokat emeljük ki, amelyeket az alábbi témákban értünk el: - A heterogén mobil hálózatok együttműködési problémái, - A mobil Internet Protokoll alkalmazásával kapcsolatos vizsgálatok, - Többfelhasználós detekciós módszerek a kódosztásos többszörös hozzáféréses mobil rendszerekben, - A heterogén mobil hálózatok forgalmi modellezése, - A mobil informatikai és távközlési hálózatok, rendszerek és szolgáltatások - biztonsági kérdései, - Kvantum számítástechnika és mérnöki alkalmazásai, - Útkeresési és csatornakijelölési algoritmusok fejlesztése és vizsgálata mobil hálózatok számára, alkalmazott gráfelmélet. A kutatásban résztvevők az eredményeket három megvédett PhD disszertációban, egy benyújtás előtt álló akadémiai doktori értekezésben és több beadás előtt álló PhD értekezésben használták fel. A tudományos iskola publikációs listája 135 elemből áll. | The members of the Scientific School have got new results in the following scientific fields: - Mobile IP, all IP networks, - Routing algorithms, - Hand-over algorithms, - Interworking of heterogeneous mobile technologies, - Quality of services (QoS), - Security problems of mobile and information networks and systems, - Multi-user detection, - Code division multiple access, - Traffic modeling, - Code construction for code division technologies, - Quantum computing, - Graph theory, - Combinatorial optimization. On the above mentioned scientific field we have the most important results in the following areas: - Interoperability issues of heterogeneous mobile networks, - Investigations on the applicability of mobile Internet Protocol, - Multi-user detection methods in code division multiple access systems, - Traffic models of heterogeneous mobile networks, - Security issues of mobile information and telecommunication networks, systems and services, - Quantum computing and its engineering applications, - Development and research of routing and channel assigning algorithms for mobile networks, application of the graph theory. The participants of the research used their results in three defended PhD theses, in a dissertation for DSc title, and in some other PhD theses before the final process. The number of the publications of the Scientific School is 135

Food safety significance of the inhibitors in milk

SUMMARY In the dairy industry starter cultures have been used for more than a hundred years in the production of dairy products which are very important in the nutri tion of humans. The authors present the biological and chemical agents which can affect the fermentation and the quality of the finished product. In this paper the possibilities of the contamination of the milk and the dairy products and also the aspects of the inhibitors in milk are demonstrated. The authors review the European and the Hungarian regulations and the screening methods which can be used in the farms or in the dairy industry. Then the presence of the inhibitors in milk or in dairy products are outlined based on the international and Hungarian monitoring results

Food toxicological impor tance of marine and fresh water biotoxins. Part II: Fish and fishery products Literature review

SUMMARY The authors summarise the chemical, toxicokinetic, toxicological and clinical properties and characteristics of biotoxins (ciguatoxins, tetrodotoxin) and bio genic amines (histamine) found in marine and freshwater fish. Biotoxins pro duced by different dinoflagellates can also be found in the body of fish and can be taken up by nutrition. However, certain fish species produce toxins that are stored in their organs and tissues. Generally, these toxins are heat-stable and resistant to gastric juice. Ciguatoxins are lipid soluble and distributed in the whole body of fish. Basically, they bind to the voltage-dependent sodium channel causing depolarisation of the membrane due to sodium influx. Consequently, they increase the influx of calcium and water into the cell leading to muscle contraction, release of neu rotransmitters, decrease of nerve stimulation and paralysis. Characteristic signs of the toxicosis are paraesthesia, nervous system signs, gastro-intestinal prob lems, and rarely cardiovascular alterations. Tetrodotoxins are particularly concentrated in the offal of fish (liver, ovary, intes tines) and the skin with lesser extent. They are potent neurotoxins and block the voltage-gated sodium channel and therefore the influx of sodium, however, having no effect on potassium ions. The symptoms of intoxication include numbness at orofacial area, paraesthesia, gastro-intestinal signs, incoordination, unable to move and general paralysis. The freshwater biotoxins produced by blue algae do not accumulate in different vectors. They act rather by direct contact with the human body and have differ ent biological effects (e.g. hepatotoxic, neurotoxic). Scombrotoxin (histamine) is a biogenic amine with potent biological action that is produced during the normal metabolism of fish or due to microbial decarbox ylation. It may be present in large quantities in fishery products which may be harmful but not fatal to the consumers. The legal official regulations which are important from the aspect of consumer’s health care are also reviewed

Food toxicological importance of marine and freshwater biotoxins Part I: Live bivalves

Summary Biotoxins produced by marine algae are taken up by shellfish during the filterfeeding activity which remain and concentrate in their different organs, thus these toxins can become the part of the human food-chain presenting potential risk to consumers. Generally, the toxin-producing algae habitat in the sea at tropical and temperate climate all over the world, however, the presence of a certain toxin may be characteristic to a given region. The authors summarise the physical-chemical characteristics of different biotoxins (saxitoxin, gonyautoxins, okadaic acid, dynophysistoxins, azaspiracids, yessotoxins, pectenotoxins, domoic acid, brevetoxin, palytoxins, cyclic imines) as food contaminants detected in marine organisms, particularly in shellfish, and their toxicokinetic profile, mechanism of action and potential harmful effects. They are called phycotoxins and most of them are lipid-soluble, heat-stable, thus the cooking and other heat-treatment or freezing does not inactivate them. Some of them - e.g. saxitoxin - are highly potent poisons. From food-toxicological aspects the paralytic shellfish poison (PSP), the diarrhoeic shellfish poison (DSP), the amnesic shellfish poison (ASP) and the neurotoxic shellfish poisoning (NSP) are the most meaningful. Furthermore, the legal regulation of toxins aiming to the health protection of consumers is also discussed. Essentially, the presence of the phycotoxins in edible marine molluscs and fish species does not induce any alterations or abnormality detectable by organoleptic examination. The base of protection against them is based on the prevention and regulation of farming and harvesting of live bivalves. According to the legal limit values and assessment performed by European Food Safety Agency, the consumption of flesh of shellfish containing okadaic acid, azaspiracid, saxitoxin and domoic acid can cause diseases in human consumers

Degradation of doxycycline in aged pig manure

Two types of studies were carried out to characterise the degradation rate of doxycycline in manure. In the laboratory experiment, pig manure containing doxycycline was stored in biochemical oxygen demand (BOD) bottles in a thermoregulated room at a temperature of 20 ± 3.5 °C to maintain the humid and anaerobic incubation conditions, and the relevant temperature. In the field study, the traditional manure composting process used by small farms and household plots was demonstrated, in which the manure heap containing doxycycline was exposed to the regular environmental conditions. In the laboratory experiment more than 30% and in the field study about 10% of the initial doxycycline amount could be detected in manure samples after 16 and 12 weeks of manure ageing period, respectively. Based on the results obtained from the studies performed under laboratory and field conditions, the half-life of doxycycline in manure was calculated to be 52.5 and 25.7 days, respectively