Occurrence of Fusarium verticillioides and Fusarium musae on banana fruits marketed in Hungary.

Fusarium strains were isolated from rotten banana fruit imported into Hungary from some African and some Neotropical countries. The strains were identified using morphological features, 2-benzoxazolinone tolerance, translation elongation factor (EF-1α) sequences and inter simple sequence repeat (ISSR) analysis. All strains from Africa proved to be F. verticillioides whereas the strains from the Neotropics are Fusarium musae. According to the PCR proof and the fumonisin toxin measurement F. musae strains cannot produce any fumonisins (FB1-4).

Detection of previously unknown fumonisin P analogue mycotoxins in a Fusarium verticillioides culture by high-performance liquid chromatography-electrospray ionization time-of-flight and ion trap mass spectrometry.

Five previously unknown fumonisin mycotoxins (iso-FP1, iso-FP(2,3a), iso-FP(2,3b), FP4 and iso-FP4) and three previously described FP analogues (FP(1-3)) were detected in a solid rice culture inoculated with Fusarium verticillioides. The fumonisins were characterized by high-performance liquid chromatography-electrospray ionization time-of-flight mass spectrometry (HPLC-ESI-TOFMS) and ion trap mass spectrometry (ITMS). The FP isomers were separated by using a flat gradient on a special, high-coverage C18, narrow-bore HPLC column (YMC-Pack J'sphere ODS H80), which was suggested for the separation of structural isomers. The verified structures of the FP(1-3) mycotoxins, the relative retention times (by HPLC-ESI-TOFMS and ITMS), the exact masses of the molecular ions (by TOFMS) and the masses of the product ions, including the hydrocarbon backbones (by ITMS) of the new compounds, strongly suggested their structures.

Fumonisin measurement from maize samples by high-performance liquid chromatography coupled with corona charged aerosol detector.

Fumonisins are a class of mycotoxins produced mainly by Fusarium species, which is primary fungal contaminant of the maize and maize-derived products around the world. The B-series fumonisins (FB1, FB2 and FB3) are the most abundant and toxic constituent; thus, their levels are regulated generally worldwide. In this study, we developed a reliable method for the measurement of fumonisin FB1, FB2 and FB3 mycotoxins from maize samples without the time-consuming derivatization step using a high-performance liquid chromatograph coupled with corona charged aerosol detector. The detection and quantitation limit of the whole method were 0.02 and 0.04 mg/kg for each fumonisins, respectively. The detection linearity was tested in the calibration range of 2 orders of magnitude and the recoveries from the spiked samples were determined. The developed method proved to be sufficient to measure the maximum residue levels of fumonisins, which are specified in European Union and United States in maize and maize-based products.

Relationships of Helicoverpa armigera, Ostrinia nubilalis and Fusarium verticillioides on MON 810 Maize.

MON 810 maize was developed against Ostrinia nubilalis and is suggested to indirectly decrease Fusarium spp. infestation in maize ears. To evaluate this effect, co-occurrence of insect and fungal pests on MON 810 maize was studied. During 2009, exceptionally high maize ear infestation occurred in Julianna-major (Hungary). From investigation of some thousands of maize ears, the majority of the larval damage originated from Helicoverpa armigera larvae, while O. nubilalis larvae contributed significant damage only at a single plot. Fusarium verticillioides infection appeared only in a small portion (~20-30%) of the insect damaged cobs. H. armigera and O. nubilalis larvae feeding on F. verticillioides mycelia can distribute its conidia with their fecal pellets. MON 810 maize showed 100% efficacy against O. nubilalis in the stem, but lower efficacy against O. nubilalis and H. armigera in maize ears. The ~Cry1Ab toxin content of maize silk, the entry site of H. armigera, was lower than that in the leaves/stem/husk leaves of MON 810. Fusarium-infected MON 810 cobs are rarely found and only after larval damage by O. nubilalis. H. armigera larvae could not tolerate well F. verticillioides infected food and attempted to move out from the infected cobs. For further feeding they re-entered the maize ears through the 8-12 husk leaves, but in the case of the MON 810 variety, they usually could not reach the kernels. Apical damage on cobs resulted in only a minor (about one-tenth of the cob) decrease in yield.

Detection and characterization of twenty-eight isomers of fumonisin B1 (FB1) mycotoxin in a solid rice culture infected with Fusarium verticillioides by reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight and ion trap mass spectrometry.

Fumonisin mycotoxins which are hazardous to humans and animals were produced in a Fusarium verticillioides-infected solid rice culture. To decrease the possibility of the formation of artifacts, the fumonisins were analysed by reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight (RP-HPLC/ESI-TOFMS) and ion trap mass spectrometry (RP-HPLC/ESI-ITMS) immediately after the extraction of the culture material, without any further sample clean-up. The fumonisin isomers were separated by using a flat gradient on a special, high-coverage C(18), narrow-bore HPLC column (YMC-Pack J'sphere ODS H80) suggested for the separation of structural isomers by the manufacturer. Exact mass measurements (TOFMS) of the protonated molecules and extraction of the ion chromatogram corresponding to the empirical formula (C(34)H(59)NO(15)) of FB(1) toxins led to the identification of 29 peaks and shoulders, including those of FB(1). The FB(1) toxin and 28 of its isomers were also detected by ITMS after separation with RP-HPLC. The characteristic m/z values of the product ions, including the backbones obtained by ITMS(2), undoubtedly indicated the structures of the FB(1) isomers for 28 peaks and shoulders. In the MS(2) spectra of the protonated molecules of the FB(1) isomers, with some exceptions, 15 characteristic product ions including the hydrocarbon backbone at m/z 299 were observed. The abundance ratio of the cation at m/z 299 ranged up to 5.8%. The relative quantities of the isomers found in the sample extract were expressed as percentages of the FB(1) content (0.001-0.579%). The total amount of the 28 FB(1) isomers was 2.803% of the quantity of FB(1) that is important from the aspect of food and feed safety.

Detection of new fumonisin mycotoxins and fumonisin-like compounds by reversed-phase high-performance liquid chromatography/electrospray ionization ion trap mass spectrometry.

Fumonisins were produced in a rice culture infected with Fusarium verticillioides. To decrease the possibility of the formation of artifacts, the fumonisins were analyzed by reversed-phase high-performance liquid chromatography with electrospray ionization ion trap tandem mass spectrometry (RP-HPLC/ESI-IT-MS2) immediately after the extraction of the culture material without any sample clean-up. In addition to already known fumonisins, numerous new fumonisin mycotoxins and fumonisin-like compounds were detected. On the basis of the IT-MS2 data, detailed fragmentation pathways including new mechanisms were proposed for the different series of fumonisins. The retention times, the masses of the protonated molecules and of the product ions including the backbones and the characteristic neutral mass losses from the protonated molecules of the new compounds suggested their structures (applying the well-known designation): iso-FA1a,b, iso-FB1a-d, iso-FB2,3a-e, PHFB2a-c, PHFB4a-d, FB5/iso-FB5a-d, FBK1 2TCA, FBK4 2TCA, FC2, iso-FC2,3, PHFC4, FD and FBX series. The relative quantities of fumonisins and fumonisin-like compounds found in the sample extract were expressed as percentages of FB1 (0.02-100%). The backbone of the compound denoted FD contained fewer carbon atoms than the well-known fumonisins with the C19 or C20 backbone and may well be a precursor of the longer compounds. For the compounds denoted FBX (12 compounds), one or two OH groups attached to the fumonisin backbone were esterified by carboxylic acids other than tricarballylic acid, such as cis-aconitic acid, oxalylsuccinic acid and oxalylfumaric acid.