Bacteria of the Pseudomonas migula genus on stored vegetables

For the study on Pseudomonas bacteria, samples of vegetables with soft rot symptoms were collected in a market place and storage-rooms. The samples were examined on selective media for Gram-negative bacteria of the genus Pseudomonas. Forty Pseudomonas strains were isolated from injured carrot roots, potato tubers, onions, leek leaves, beetroots, cabbages, radish. On the basis of biological tests the bacteria were ascribe to 10 Pseudomonas species: P. fluorescens, P. marginalis, P. putida, P. facilis, P. aeruginosa, P. delafieldii, P. cichorii , P. pseudoalcaligenes, P. cepacia (=Burkholderia cepacia), P. gladioli (=Burkholderia gladioli pv. aliicola). Five species isolated from potato tubes, carrot roots, onions, and beetroots – P. fluorescens, P. marginalis, P. cichorii, P. cepacia (= Burkholderia cepacia), and P. gladioli (=Burkholderia gladioli pv. aliicola) – were able to cause soft rot symptoms of various vegetables.Z warzyw przechowywanych w różnych warunkach na pożywkach sztucznych wydzielono 40 patogenów rodzaju Pseudomonas. Po sprawdzeniu właściwości biologicznych bakterii stwierdzono, że s to gatunki P. fluorescens, P. marginalis, P. putida, P. facilis, P. aeruginosa, P. delafieldi, P. cepacia (=Burkholderia cepacia), P. cichorii, P. alcaligenes ir P. gladioli pv. aliicola (=Burkholderia gladioli pv. aliicola). W wyniku przeprowadzonych testów na określenie patogeniczności bakterii stwierdzono, że pięć spośród wyizolowanych okazało się patogenicznymi: P. fluorescens wyizolowana z bulw ziemniaka, korzeni marchwi i cebuli, P. marginalis wyizolowana z bulw ziemniaka, P. cepacia, z korzeni marchwi i cebuli, P. cichorii, wyizolowana z korzeni marchwi oraz P. gladioli wyizolowana z cebuli. Wykazano, że niektóre gatunki bakterii mogą być patogeniczne i powodować zgniliznę warzyw. Porażone warzywa mogą być pierwotnym źródłem zakażenia zdrowych warzyw. Nieliczne spośród tych bakterii są chorobotwórcze dla zwierząt i człowieka

Problems of a longtime strawberry growing in one plot

Long term investigations revealed that cultivation of strawberries (Fragaria magna Thuill.) for 10 years continuously in one plot reduces their vitality: the number of the produced runners decreases by 41%, of leaves – by 30%, form only 28% of inflorescence, the yield reduces by 50% in comparison with strawberries grown for two years in a new plot. Evident decline in the vitality and productivity of strawberries was detected during 4th–6th years of cultivation. Unequal reaction of the tested cultivars upon the durability of cultivation was noticed; strawberries of the cultivar ‘Senga Sengana’ reacted slightly, while the ones of the cultivar ‘Nida’ – strongly. It is related with different sensibility of these cultivars towards the disease agents of root rots. It was determined that long-term cultivation of the Fragaria genus plants results in the accumulation of the parasitic fungi propagules in soil: Ascochyta fragaricola, Cercospora fragariae, Fusarium oxysporum, F. solani, Perenospora fragariae, Phytophthora cactorum, Pythium intermedium, P. ultimum, Plasmodiophora brassicae, Sclerotium rolfsii, Verticillium alboatrum. Therefore, cultivation of strawberries in the same plot for longer time increases the phytopathogenic potential of soil, and short interval (1–2 years) between planting has little significance upon it. The second reason for low productivity of strawberries cultivated for a long in one plot is soil tiredness caused by fungi, synthesising and excreting into surrounding toxic secondary metabolites, widespread in the rhizosphere, especially those belonging to the Penicillium genus: P. janthinellum, P. verruculosum var. verrucosum, P. canescens, P. spinulosum.Wieloletnie badania wykazały, że uprawa truskawki (Fragaria magna Thuill.) na jednym polu przez 10 lat spowodowała zahamowanie ich wzrostu i rozwoju. Uprawiane w ten sposób truskawki tworzą o 41% mniej rozłogów, o 30% mniej liści, o 28% mniej kwiatostanów oraz tworzą o 50% mniej owoców w porównaniu z truskawką uprawianą przez dwa lata na danym polu. Najczęściej do obniżenia wzrostu i plonowania truskawki dochodzi w 4–6 roku uprawy. Nie wszystkie uprawiane odmiany reagują jednakowo obniżeniem wzrostu i plonowania. Najmniej podatną na choroby korzeni jest odmiana ‘Senga Sengana’, natomiast bardziej podatna okazała się odmiana ‘Nida’. Stwierdzono, że długotrwała uprawa truskawki powoduje wzrost potencjału infekcyjnego gleby, co związane jest ze wzrostem jednostek propagacyjnych takich grzybów chorobotwórczych, jak Ascochyta fragaricola, Cercospora fragariae, Fusarium oxysporum, F. solani, Peronospora fragariae, Phytophthora cactorum, Pythium intermedium, P. ultimum, Plasmodiophora brassicae, Sclerotium rolfsii, Verticillium albo-atrum. W wyniku prowadzonych badań wykazano, że 1-2 letnia przerwa w uprawie truskawki nie ma większego wpływu na wzrost i plonowanie oraz porażenie roślin truskawki przez fitopatogeny. Ponadto przy długotrwałej uprawie truskawki na tym samym polu zwiększa się liczebność grzybów z rodzaju Penicillium: P. janthinellum, P. verruculosum, P. canescens, P. spinulosum. Przypuszcza się, że grzyby te w strefie korzeniowej roślin tworzą związki fitotoksyczne będące produktami ich metabolizmu

Preventive measures reducing superficial mycobiotic contamination of grain

Search for the preventive measures reducing the accumulation of mycotoxin producers in food raw material was carried out. Active ventilation was used; the impact of the electro-chemically activated air (ozone) and electro-chemically activated water (anolyte) on the micromycetes prevailing in grain raw material for food (GRMF) was determined. The GRMF was dried by active ventilation using the ozone-air mixture. Ozone (concentration 1250 ppb) disinfects the surface of the raw material and creates conditions unfavourable for the increase of mycobiotic contamination in drying upper layers of the grain mound. Within 8 days the contamination of GRMF in a mound decreased by 50%, while in its lower layers – more than 3 times. Ventilation of the mound with the above-mentioned concentration of the ozone-air mixture has ceased the active functioning of Fusarium avenaceum, F. graminearum, F. poae, F. solani, F. tricinctum F. sporotrichioides micromycetes and has considerably retarded the development of Alternaria alternata and other fungi. Anolyte (0.05% of chlorine concentration) reduced the mycobiotic contamination of GRMF by almost 2.5 times. The optimal treatment duration is from 0.5 to 1 hour. The optimal technical parameters, allowing the use of these measures for the preparation of grain food safety technologies, were elaborated; they are designed for more efficient protection of human health against micromycetes and their toxic metabolites, which are abundantly produced and released into the environment

Fault Tree Analysis for Fungal Corrosion of Coated Aluminum

A fault tree methodology has been used to analyze the combinations of basic factors involved in fungal degradation and corrosion. The purpose was to demonstrate the identification of mitigation actions for reducing the risk of fungal corrosion of coated aluminum in aircraft. The interaction between fungal-induced degradation processes and coatings is described, and the methodology of the fault tree analysis (FTA) is presented. The interconnection of the basic factors through conventional AND and OR logic gates in the fault tree structure reveals vulnerabilities and potential failure pathways in the system. Mitigation actions can be directed at these basic factors to reduce or eliminate failure pathways, thereby reducing the overall risk of fungal-induced corrosion. Potential applications of FTA for corrosion mitigation, design and materials selection, and failure analysis are presented

Factors determining accumulation of mycotoxin producers in cereal grain during harvesting

During the meteorologically contrasting period of 2003-2005, the contamination of winter wheat, malt barley and fodder barley grain with micromycetes during grain harvesting and preparation for storage was investigated. Micromycetes of over 70 species ascribed to 16 genera were isolated and identifi ed, the density of their populations in grain was determined. Micromycetes with a population density of >50% were attributed to dominant species. Short biological characteristic, ecological peculiarities of the dominating micromycetes are provided; factors determining intensity of their development and abilities to synthesise and excrete toxic metabolites are indicated. The importance of grain drying for stabilisation of its contamination with micromycete propagules is highlighted. It is noted that in grain dried in shaft dryer using air at 90°C the number of cfu (colony forming units) was reduced from 2.2 to 8.2 times. When active ventilation is applied, conditions favourable for the development of micromycetes remain longest in the upper layers of the mound. The airfl ow passing through the layer of damp grain inhibits the development of micromycetes, but an increase of comparative air fl ow for more than 500 m3·(t·h)-1 did not reduce the abundance of micromycete cfu. After drying Alternaria alternata, Fusarium avenaceum, F. culmorum, Penicillum verrucosum dominated in wheat grain; Aspergillus fl avus, Bipolaris sorokiniana, Fusarium chlamydosporum, F. culmorum, F. tricinctum in malts barley grain; Fusarium avenaceum, F. culmorum, F. tricinctum, Alternaria alternata in fodder barley grain. It has been determined that all micromycetes recorded on grain after drying are potential producers of toxic metabolites, i.e. are hazardous to human health