Toxigenic and allergen-producing fungi represent a serious hazard to human food and animal feed safety. Ninety-four fungal species were isolated from mite-infested samples of seeds taken from Czech seed stores. Fungi were isolated from the surface of four kinds of seeds (wheat, poppy, lettuce, and mustard) and from the gut and external surface of five species of mites (i.e., Acarus siro L., 1758, Caloglyphus rhizoglyphoides (Zachvatkin, 1973), Lepidoglyphus destructor (Schrank, 1781), Tyrophagus putrescentnae (Schrank, 1781) and Cheyletus malaccensis Oudemans 1903) separately. Multivariate analysis of fungi complex composition showed that the frequency of fungal was species significantly influenced by the kind of seed. Fungal frequencies differed between mites gut and exoskeleton surface and between the surfaces of mites and seeds. Three groups of fungal species were recognized: 1) mite surface-associated fungi: Penicillium brevicompactum, Alternaria alternata, and Aspergillus versicolor; 2) mite surface- and seed-associated fungi: Aspergillus niger, Penicillium crustosum, Penicillium aurantiogriseum, Penicillium chrysogenum, and Aspergillus flavus; and 3) seed-associated fungi: Cladosporium herbarum, Mucor dimorphosporus f. dimorphosporus, Botrytis cinerea, Penicillium griseofulvum, and Eurotium repens. Mite-carried species of microfungi are known to produce serious mycotoxins (e.g., aflatoxin B1, cyclopiazonic acid, sterigmatocystin, ochratoxin A, and nephrotoxic glycopeptides) as well as allergen producers (e.g., A. alternata and P. brevicompactum). Storage mites may play an important role in the spread of some medically hazardous micromycetes. In addition, these mite-fungi associations may heighten the risk of occurrence of mycotoxins in food and feed stuffs and cause mixed contamination by fungal and mite allergens.

Mites are well documented as vectors of micromycetes in stored products. Since their vectoring capacity is low due to their small size, they can be serious vectors only where there is selective transfer of a high load of specific fungal species. Therefore the aim of our work was to find out whether the transfer of fungi is selective. Four kinds of stored seeds (wheat, poppy, lettuce, mustard) infested by storage mites were subjected to mycological analysis. We compared the spectrum of micromycete species isolated from different species of mites (Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, Caloglyphus rhizoglyphoides and Cheyletus malaccensis) and various kinds of stored seeds. Fungi were separately isolated from (a) the surface of mites, (b) the mites' digestive tract (= faeces), and (c) stored seeds and were then cultivated and determined. The fungal transport via mites is selective. This conclusion is supported by (i) lower numbers of isolated fungal species from mites than from seeds; (ii) lower Shannon-Weaver diversity index in the fungal communities isolated from mites than from seeds; (iii) significant effect of mites/seeds as environmental variables on fungal presence in a redundancy analysis (RDA); (iv) differences in composition of isolated fungi between mite species shown by RDA. The results of our work support the hypothesis that mite-fungal interactions are dependent on mite species. The fungi attractive to mites seem to be dispersed more than others. The selectivity of fungal transport via mites enhances their pest importance.

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Stored-product pests cause high economic losses by feeding on stored grain and endanger the public health by contamination of food by allergens. Therefore, the aim of this work was to explore whether the risk of infestation of stored grain by pests is different in various types of storage premises. We compared the level of infestation and the pest species composition in the two main types of grain stores in Central Europe that includes horizontal flat-stores (HFS) and vertical silostores (elevators) (VSS). A total of 147 grain stores located in Bohemia, Czech Republic was inspected. We found that both types of stores were infested with arthropods of three main taxonomic groups: mites (25 species, 120 000 individuals), psocids (8 species, 5 600 individuals) and beetles (23 species, 4 500 individuals). We found that VSS and HFS differ in species composition of mites, psocids and beetles. However, the primary grain pests (i.e. Lepidoglyphus destructor, Acarus siro, Tyrophagus putrescentiae, Lachesilla pedicularia, Sitophilus oryzae, Rhyzopertha dominica, Oryzaephilus surinamensis and Cryptolestes ferrugineus) occurred in both types of stores. The only exception was higher frequency and abundance of two serious beetle-pests (Tribolium castaneum, Sitophilus granarius) in HFS than in VSS. The total numbers of mite and beetle species infesting VSS and HFS was almost the same. There was higher psocid species diversity in VSS than in HFS. The difference between the total (i.e. level of pest infestation per kg of grain sample) numbers of mite and psocid individuals collected from VSS and HFS was not significant. However, the total numbers of beetle-pest individuals collected from HFS was twice the amount collected from VSS. We concluded that both types of stores are equally risky in terms of mite and psocid infestation. HFS is more risky for grain storage than VSS in terms of beetle infestations, although even the VSS structures cannot be in no way called pest-safe. The VSS and HFS microclimatic conditions (humidity, temperature) are discussed in relation to mite, psocid and beetle infestation.Keywords: food; grain; storage; silo; bulk stores; pests; mites; psocids; beetles Production of grain-crops at the farm level is a valueadded agricultural process that includes both field planting and storage of grain. The economical outcome of this process is influenced by many biotic and abiotic factors and their mutual interactions. Infestation of grain by arthropods belongs among the most economically important biotic factors; since these pests cause enormous losses of stored products each season worldwide (Subramanyam and Hagstrum 1996). The type of storage technology is considered a serious abiotic factor influencing the stored-grain quality. Industrial buildings differ in their level of isolation to prevent colonisation by outdoor pests (Murphy and Todd 1993). For example, Mann et al. (1999) found that adults of Cryptolestes ferrugineus were unable to infest wheat grain stored in sealed metal bincontainers. It is also...