Aspergillus, Penicillium, and Fusarium species frequently contaminate crops. For this reason mycotoxins such as afl atoxins (AFs), ochratoxin A (OTA), fumonisins (FBs), and zearalenone (ZEA) are found in food and feed in a wide range of concentrations, depending on environmental and storage conditions. Consumption of mycotoxin-contaminated food and feed has been associated with acute and chronic poisoning and carcinoma. The aim of this study was to determine the incidence and co-occurrence of AFs (B 1 +B 2 +G 1 +G 2 ), OTA, FBs (B 1 +B 2 +B 3 ), and ZEA in 37 samples of cereals and feed randomly collected in 2007 from households of an endemic nephropathy (EN) area in Croatia. The mycotoxins were determined using the competitive direct ELISA test (CD-ELISA) in combination with thin-layer chromatography (TLC). The most frequent mycotoxin was ZEA (92 %, mean 318.3 µg kg -1 ), followed by FBs (27 %, 3690 µg kg -1 ), AFs (24.3 %, 4.6 µg kg -1 ), and OTA (16.2 %, 9.8 µg kg -1 ). Levels of AFs, ZEA, and FBs detected by CD-ELISA signifi cantly correlated with the TLC results. However, only one OTA-positive sample was confi rmed by TLC due to its high limit of detection. The levels of these mycotoxins were below the permissible limit for animal feed. Twenty-nine percent of cereals were contaminated with FBs, OTA, or ZEA in mass fractions above the permissible limit for humans. Co-occurrence of two toxins varied between 4.2 % and 54 % and of three between 4.2 % and 7.6 %. Prolonged co-exposure to AFs, OTA, FBs, and ZEA might increase the risk of various chronic diseases.

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Over a period of three years 420 samples of various smoke-dried meat products, collected from individual households in different region of Croatia were analysed for the presence of aflatoxigenic strains of the Aspergillus flavus group. Strains of A. flavus and A. parasiticus were present in 17.8% of the samples, and aflatoxin-producing ability was tested in 75 strains. In relation to sequential method of aflatoxin detection, 5 of 8 isolates were found in the first step (fluorescence in aflatoxin-producing ability medium--APA) and all of them in the second step (extraction method from syntheses on moist shredded wheat--SW). A. flavus strains produced mainly aflatoxin B1, and had various levels of toxigenicity (1.4-3.12 mg/kg). Some strains of A. parasiticus produced all four aflatoxins B1 B2 G1 G2, while the other ones produced AF B1 + G1 only, with concentrations of aflatoxins from 0.1 to 450 mg/kg.

The objective of this study was to evaluate biotic interaction between some mould species and active producer of aflatoxin B 1 Aspergillus flavus NRRL 3251, co-cultured in yeast-extract sucrose (YES) broth. Twenty-five mould strains of Alternaria spp., Cladosporium spp., Mucor spp., A. flavus and A. niger, used as biocompetitive agents, were isolated from outdoor and indoor airborne fungi, scrapings of mouldy household walls, and from stored and post-harvest maize. Aflatoxin B 1 was extracted from mould biomasses with chloroform and detected using the multitoxin TLC method. The results confirm antagonistic interaction between all strains tested. With Alternaria spp. and Cladosporium spp., aflatoxin B 1 production decreased 100 %, compared to detection in a single culture of A. flavus NRRL 3251 (C mean =18.7 µg mL -1 ). In mixed cultures with Mucor spp., aflatoxin B 1 levels dropped to (5.6-9.3) µg mL -1 , and the inhibition was from 50 % to 70 %. Four of five aflatoxin non-producing strains of A. flavus interfered with aflatoxin production in mixed culture, and reduced AFB 1 productivity by 100 %. One strain showed a lower efficacy in inhibiting AFB 1 production (80 %) with a detectable amount of AFB 1 3.7 µg mL -1 when compared to control. A decrease in toxin production was also observed in dual cultivation with A. niger strains. It resulted in 100 % reduction in three strains), 90 % reduction in one strain (C mean =1.9 µg mL -1 ) and 80 % reduction in one strain (C mean =3.7 µg mL -1 ) inhibition.

Mycological analyses of 855 samples of stored grains and dried meat collected in period 1980-1987 from individual households in the nephropathic and wider non-nephropathic area in SR Croatia in Yugoslavia showed 10% of samples to be contaminated with Aspergillus ochraceus. Ability to produce ochratoxin A (OA) was tested in 70 samples (27 from nephropathic areas and 43 from non-nephropathic areas). The detection was carried out under UV-light (365 nm) (light blue fluorescence) and 6 OA-producers were found. A biosynthetic procedure on liquid nutritional substrate with saccharose and yeast extract as well as a method using wet crushed wheat revealed that 37% of the samples from a nephropathic area, and 35% of the samples from a non-nephropathic area produce OA. In the nephropathic area 1/10 strains was a strong producer of OA (concentration crushed wheat 135 mg/kg, and 240 mg/l on YES liquid substrate), 1/10 strains was a moderate producer (concentration 16.6 mg/l and 0.07-7.0 mg/l and 0.1-10.4 mg/kg). Among the strains isolated from a wider non-nephropathic area no strong producers of OA were found, but 2/15 strains were moderate producers of OA (concentration of OA 20.4-27.0 mg/l and 15.0-33.7 mg/kg). The other strains, 8/10 on the crushed wheat and 13/15 on the liquid substrate, were weak producers of OA with concentrations of OA between 0.2-9.0 mg/l and 0.2-10.0 mg/kg with the two methods respectively.