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In this study, contamination by microscopic fungi (focused on Penicillium and Aspergillus species) of 75 fruit samples (strawberries, blackberries, blueberries, raspberries, grapes) and 29 tomato samples, which were obtained from Slovak stores was investigated. Totally 93.3% of fruit samples were contaminated with micromycetes (70.6% Botrytis spp., 52.0% Cladosporium spp., 42.7% Penicillium spp., 13.3% Rhizopus spp., 8.0% Alternaria spp., 6.7% Mucor spp., 5.3% Aspergillus spp., 4.0% Fusarium spp., and 1.3% Epicoccum spp.) and 6.7% of samples were contaminated with yeasts. The presence of 15 species of the genus Penicillium in fruits, namely P. atramentosum, P. aurantiogriseum, P. brevicompactum, P. bialowiezense, P. citrinum, P. crustosum, P. digitatum, P. expansum, P. fellutanum, P. glabrum, P. hordei, P. italicum, P. kiamense, P. olsonii, and P. purpurescens was found. With the highest frequency, P. brevicompactum (12.0%) and P. expansum (10.7%) were isolated from fruits. Four isolates of the genus Aspergillus were isolated from fruit samples (A. section Clavati, A. section Flavi, and two isolates of A. section Nigri). Thin layer chromatography (TLC) was used for testing of mycotoxin production by selected fungal isolates. Overall, 93.3% of tested Penicillium isolates and one tested Aspergillus of section Clavati proved the ability to produce at least one of the tested mycotoxins. As for tomato samples, 93.1% were contaminated with microscopic filamentous fungi (79.3% Penicillium spp., 24.1% Botrytis spp. and Alternaria spp., 10.3% Cladosporium spp., Mucor spp. and Rhizopus spp., 6.9% Aspergillus spp. and 3.4% Fusarium spp.) and 6.9% samples were contaminated with yeasts. In 65.5% of tomato samples, the occurrence of 8 species of the genus Penicillium (P. brevicompactum, P. crustosum, P. expansum, P. griseofulvum, P. italicum, P. olsonii, P. sublectaticum, P. thomii), and two species of the genus Aspergillus (from section Circumdati and Flavi) was recorded. P. olsonii (58.6%) and P. griseofulvum (10.3%) were isolated with the highest frequency. All 7 tested Penicillium isolates (100.0%) and 1 isolate of the genus Aspergillus (section Flavi), which were obtained from tomatoes, had the ability to produce at least one of the tested mycotoxins. Aspergillus section Flavi isolate (from tomatoes of Slovak origin) produced 5.5 μg.mL-1 of aflatoxin B1, 4.2 μg.mL-1 of aflatoxin B2, 154.4 μg.mL-1 of aflatoxin G1, and 5.6 μg.mL-1 of aflatoxin G2 on 14th day of cultivation on liquid YES medium at 25±1 °C in darkness, and detected by high pressure liquid chromatography (HPLC). [ABSTRACT FROM AUTHOR]

This study aimed to investigate the antagonistic effect of three strains of the genus Bacillus on toxigenic fungi contaminating food commodities, with emphasis on two ochratoxigenic isolates (A. ochraceus, A. westerdijkiae) and two aflatoxigenic isolates (A. flavus and A. parasiticus). In vitro studies were carried out using two different methods for cultivation tested bacilli with fungal isolates - coincubation and dual culture method. The most sensitive isolate was A. ochraceus by both used methods. B. mycoides (5.72 ± 6.4 mm) and B. subtilis (5.08 ± 2.84 mm) were able to inhibit its growth and sporulation during ten days of cultivation (both inhibited the sporulation of A. ochraceus 100%) in coincubation. The most effective in the dual culture method were B. subtilis and B. thuringiensis against A. ochraceus (growth inhibition rate 84.40%; 90.55%) and A. flavus (growth inhibition rate 91.54%; 92.43%). The most effective sporulation inhibitors were B. subtilis and B. thuringiensis, which completely inhibited the sporulation of A. ochraceus and A. parasiticus after ten days of coincubation. Likewise, all tested bacterial strains showed complete inhibition of ochratoxin A synthesis in A. ochraceus and A. westerdijkiae exposure to bacterial volatiles. So, the current study illustrated that strains of the genus Bacillus could significantly inhibit the growth, sporulation, and mycotoxin production of toxigenic aspergilli and showing the great potential as a biocontrol agent of preand post-harvest food diseases caused by microscopic filamentous fungi. [ABSTRACT FROM AUTHOR]