Botanica Lithuanica , Supplementum 7

2005 m.

In 2002–2004, investigations on evolution of contamination of grain, seeds and other food products of plant origin grown in Lithuania and imported from different countries were performed in various premises of storing, sale, and processing under diverse conditions of production preservation. For mycological investigations, 1024 samples of 102 product types were taken. After the analysis of food product samples, 408 species of micromycetes ascribed to 89 genera, 26 families, 13 orders, 3 classes, 6 phyla were identified. Composition of micromycetes in the investigated premises depended upon diversity of the analyzed products, their origin, quality of the environment of their storing and preventive measures.

Keywords: grain, seeds, vegetables, fruit, food, raw materials, products, micromycetes, mycotoxins.

At the Lithuanian Institute of Agriculture (Dotnuva) in 2004, eighteen winter and eighteen spring cereal commercial varieties were sown in a field certified for organic farming. Naturally contaminated organic grain samples were analyzed for occurrence of toxic fungi and Fusarium toxin deoxynivalenol (DON). Experimental results showed that organic grain were heavily contaminated and infected with toxic fungi and were not free from mycotoxins. Species Alternaria, Cladosporium, Fusarium were more frequent on grain surface. The most prevalent of toxic fungi in freshly harvested organic grain were Alternaria spp. Infection with Fusarium spp. in grain was higher in spring than in winter cereals. Aspergillus spp. and Penicillium spp. infection level in freshly harvested grain was very low and no significant differences were determined. DON was detected in all analyzed samples, but toxin concentration was low. Host-plant, variety and weather conditions influenced infection level of organic grain.

Keywords: toxic fungi, Fusarium, mycotoxins, DON, organic grain.

Results of field research on the efficacy of fungicides upon Fusarium head blight (FHB) on winter wheat ‘Zentos’ and laboratory analyses of grain contamination with micromycetes and mycotoxins are presented. Effect of strobilurin (pyraclostrobine+epxiconazole 200+75 g ha-1 a.i.) and triazoles propiconazole (125 g ha-1 a.i.) and tebuconazole (250 g ha-1 a.i.) on FHB incidence and severity as well as grain contamination with micromycetes at different maturity stages are reported for the period of 2003–2004. Efficacy of fungicides on FHB depended on the application timing and environmental conditions of the season. The data on the impact of fungicides on post-harvest grain infection with Fusarium spp. and contamination with mycotoxins deoxynivalenol (DON), zearalenone (ZEN) and T-2 were contradictory. As a result, further investigation is needed.

Keywords: winter wheat, Fusarium, head blight, fungicide, mycotoxin.

The article deals with potato storage technologies, ways of microclimate formation in potatoes stored in bulk, the impact of these factors on quality preservation and prevalence of micromycetes on stored tubers. It was established that throughout the whole storing period biological activity of potatoes stored with periodic ventilation was lower than of those stored with continuous ventilation. Storing in periodic ventilation stores ensured stable quality of potatoes. In intervals without ventilation in a thick layer of potatoes the optimal microclimate is set and in pores of the bulk autoregulation processes of microclimate proceed. Micromycetes prevalence on stored tubers is mostly affected by temperature fluctuation in the potato bulk which raises condensation processes.

Keywords: potatoes, storage, ventilation, microclimate, quality, contamination, micromycetes.

Investigation on fungal contamination of fruit and berries showed that ‘Cortland’ and ‘Lobo’ apples were mostly contaminated by fungi Penicillium expansum and P. italicum. Fungal species diversity was higher on stored apples than on freshly harvested ones. Treatment with the fungicide Zato at 0.15 kg/ha did not show evident influence on decrease of superficial apple contamination by micromycetes. Fruits of cherry ‘North Star’ were mostly deteriorated by Penicillium corymbiferum, P. granulatum and P. italicum. The most effective measure against spreading of toxin-producing fungi on cherry fruits was the mixture of Euparen M and Zato at 2.5 kg/ha. Black currant ‘Ben Nevis’ berries were mostly contaminated by the Penicillium genus fungi, and fungicides Signum at 1 kg/ha and Candit at 0.2 kg/ha were the most effective measures, reducing spreading of toxin-producing fungi.

Keywords: fungal contamination, toxins, apples, cherries, black currants, fungicides.

Recently aiming to enrich and add variety to nutrition, many raw materials and products of plant origin have been imported from various regions. Investigations on mycological state of the imported foodstuffs revealed that the marketed fruit, desiccated fruit, vegetables, nuts were contaminated by propagules of various micromycetes. The obtained results allow the conclusion that vegetables and fruit can become a good substrate for mycotoxin producing micromycetes. Some microorganisms, especially micromycetes of some species belonging to the Penicillium Link, Aspergillus Mich. : Fr., and other genera, are able to produce secondary metabolites (mycotoxins) of various compositions that are toxic to plants, animals and humans. Most of the researched micromycetes belonged to the Penicillium, Aspergillus and Alternaria Nees genera. Their detection frequency on the investigated fruit, nuts and vegetables was determined. Most of micromycete strains developing on incorrectly preserved fruit, seeds and vegetables, produce toxic secondary metabolites that pose a potential health hazard for people eating the foodstuffs.

Keywords: micromycetes, contamination, vegetable, fruit, products.

In 2003–2004, micromycetes producing toxic metabolites were isolated from food raw material and various sources directly contacting it. Fungi were identified and deposited to the pure culture collection. Evaluation of factors determining contamination of food products was carried out periodically, beginning with the investigation on contamination of grain, seeds, flax-seeds, vegetables, potatoes, fruit, and finishing up with testing of produced products. It is very important to find out if fungi that contaminate grain or vegetables can produce and excrete toxic substances into surrounding. Some fungal species potential toxin producers were detected both on the surface and inside the grain. Specific composition of fungi was detected on seeds of rape, maize, soy and their products. The most frequent fungi were as follows: Aspergillus niger, A. clavatus, A. vesicolor, Fusarium oxysporum, F. avenaceum, Penicillium expansum, P. palitans, P. roquefortii, P. viridicatum, Alternaria alternata, Rhizomucor pusillus. These fungi were predominant in the air of grain, vegetable and fruit storehouses. Micromycetes most intensively producing toxins were detected and intensity of the synthesis was ascertained. More active strains belong to these species: Alternaria brassicae, A. pluriseptata, Chrysosporium merdarium, Fusarium solani, Fusarim sp. 1-pn, Penicillium expansum, Penicillium sp. sv.-161-1. The most interesting and dangerous are strains producing more than one toxic secondary metabolite. The thin-layer chromatography constants for secondary metabolites T-2 toxin, nivalenol, neosolanol, deoxynivalenol, zearalenone, alternariol, alternuene, tenuazonic acid were determined. Micromycetes of the Penicillium genus, isolated from various food sources, produced patulin, penitrem, citochalazin, tenuazonic acid, sterigmatoscistin.

Keywords: grain, seeds, vegetables, fruit, mycotoxins, fungi, food, Lithuania.

Selection of toxin-producing micromycetes detected on grain, was carried out. More micromycetes (6) able to synthesise secondary metabolites were detected on barley. Four mycotoxin producers were identified on wheat. Fusarium poae, F. sporotrichioides and F. equiseti showed abundant excretion of pigment into CYA medium. The most abundant pigmentation on YES medium was excreted by Trichosporiella ceribriformis. Silica gel method enabled to determine that Fusarium poae, F. sporotrichioides, F. tricinctum produced T-2 toxin. Micromycete Penicillium viridicatum produced ochratoxin, Penicillium variabile – patulin and penitrem, and Alternaria alternata – tenuazonic acid.

Keywords: grain, micromycetes, mycotoxins, chromatography, pigments.

Data on the influence of Penicillium sp. in vivo and in vitro are presented in this paper. The body weight and haematological data on experimental mice as well as toxic activity of Penicillium metabolites patulin and ochratoxin A in blood-derived cell culture were estimated. It was detected that Penicillium variabile influenced the body weight of experimental mice, while the main haematological data of the tested animals were within the physiological range. Nevertheless, the experimental group demonstrated an increase in hematocrit value as compared to the control group. For the understanding of the mycotoxin mode of action in the organism, we analyzed toxic activity of Penicillium metabolites patulin and ochratoxin A in cell culture in vitro. Human promyelocytic leukemia HL60, chronic myelogenous leukemia K562 and B cell precursor leukemia REH cell lines were used as a model system of blood cells. Quantitative analyses of the proliferation and mode of cell death of haemopoetic cell lines after mycotoxins treatment revealed that all studied cells were more sensitive to patulin than ochratoxin A. The most resistant to the mycotoxins’ treatment were K562 cells. Apoptotic process was more intensive after ochratoxin A effect.

Keywords: Penicillium, toxicity, ochratoxin A, patulin, cell culture.

The applied measures of microclimate regulation are not sufficient to stop spreading of micromycetes onto the stored production. The article deals with chemical, mechanical and technological preventive measures used against micromycetes as well as the improvement of mycological state of storehouses. It was determined that disinfection of a storehouse with Menno Florates solution eliminates micromycetes of only some species and, moreover, stimulates the appearance of other species. Preservation measures against potato sprouting, automatic control of ventilation systems, washing of storehouse walls and cleaning of storehouses reduce the contamination of the storehouse air with micromycetes. The applied mechanical and chemical measures improve the mycological state of the storehouse only during initial stage of storage.

Keywords: storehouses, vegetables, potatoes, apples, micromycetes, contamination, prevention.

During the period of 2003–2004 microbial contamination of barley, wheat and other grain as well as grain processing premises was investigated. The research was carried out in a mill, premises for concentrated fodder and groats production. It was determined that technological operations of grain surface cleaning twice reduced microbial contamination in grain products. After the process of extrusion, microbial contamination of concentrated fodder was reduced by almost 70 %. In the air of industrial premises potentially toxic micromycetes were recorded.

Keywords: grain processing technologies, extrusion, micromycetes.

Commonly not driers but active ventilation is used for grain drying in small- and average-scale farms. It is a cheap and universal way of drying; however, grain in a mound becomes dry unevenly. The drying occurs in a narrow mound layer only, i.e. in the drying zone. Process of drying using active ventilation involves the formation of the zone at the air entrance location, the shift of the zone in the direction of the air flow, and its vanishing in the top layer of the mound where almost all the grain keeps the initial moisture till the end of the drying process. As a result, moist and warm medium that is hospitable for the development of the micromycetes forms. When selecting the active ventilation modes, the most important thing for the grain in the top mound layers is to become dry before it goes bad. It is the only condition for the successful drying using the active ventilation.

Keywords: grain, drying, active ventilation, micromycetes.

Mycotoxins are secondary metabolites secreted by fungi, mostly belonging to the genera Aspergillus Mich. : Fr., Penicillium Link and Fusarium Link. Mycotoxin-containing feed can cause serious diseases in farm animals. The presence of mycotoxins in feed may decrease feed intake and affect animal performance. The most applied method for protecting animals against mycotoxicosis is the utilization of adsorbents mixed with the feed, which are supposed to bind the mycotoxins efficiently in the gastro-intestinal tract. The most promising approach to decontaminate feed is a biological detoxification.

Keywords: adsorbents, biological detoxification, fungi, mycotoxins, yeast.