Transgenic versus conventional corn: fate of fumonisins during industrial dry milling.

The aim of this study was to compare the fate of fumonisins in transgenic and non-transgenic corn during industrial dry milling. For this purpose, whole corn samples and their fractions (germ, pericarp, endosperm, corn meal, and grits) were collected from one of the major Brazilian milling plants, totaling 480 samples. There was no significant difference (p > 0.05) between mean fumonisin (FB1 + FB2) levels in transgenic (1130 µg/kg) and non-transgenic (920 µg/kg) whole corn. However, in non-transgenic germ, endosperm and corn meal fraction fumonisin levels were higher (2940 µg/kg, 250 µg/kg and 190 µg/kg, respectively) than in transgenic fractions (2180 µg/kg, 130 µg/kg and 85.0 µg/kg, respectively). Furthermore, the highest percentages of fumonisins were distributed in the germ, corresponding to about 87 and 76% of the total fumonisins present in the whole corn from non-transgenic and transgenic hybrids, respectively. Concerning the endosperm from non-transgenic and transgenic corn, approximately, 23% and 13% of the total fumonisins were retained after the dry milling. Further processing in corn meal (300 to 420 µm particle size) and grits (590 to 1190 µm) decreased the percentages of remaining fumonisins to 4% and 2% (transgenic) and 10% and 3% (non-transgenic corn), respectively. These results suggested that fumonisin concentration was higher in outer and inner non-transgenic fractions when compared to transgenic ones and that the fate of fumonisins during the industrial dry milling could be affected by the transgenic status. However, it was not possible to conclude that the difference was exclusively due to this variable.

Safety of Corn and Corn-Based Products Intended for Human Consumption Concerning Fumonisins from a Brazilian Processing Plant.

Brazil is one of the world's largest corn producers and is a leader in exportation. Due to intense globalization, corn may be commercialized worldwide and the issue concerning the safety of corn-based products has become a topic of widespread international interest. Dietary exposure evaluation is a relevant criterion for mycotoxin risk assessment. Thus, human exposure to fumonisins were assessed for corn grain and its derivatives (endosperm, cornmeal, and grits; n = 320) sampled from one of the large-scale corn processing plants in Brazil. The total probable daily intake (PDI) for fumonisins in Brazil was 96.9 ng kg-1 body weight day-1, which corresponds to 5% of the provisional maximum tolerable daily intake (PMTDI) of 2000 ng kg-1 b.w. day-1 for fumonisins. In countries that import Brazilian corn, the total PDI is lower in European countries (from 35.7 to 177 ng kg-1 b.w. day-1) and higher in Angola (1553 ng kg-1 b.w. day-1). Taking into account that dietary exposure in populations in Brazil and importing countries was low, the corn-based products were safe for human consumption regarding fumonisins, even for regions with high corn consumption.

Impact of industrial dry-milling on fumonisin redistribution in non-transgenic corn in Brazil.

The aim of this study was to evaluate the fate of fumonisins B1 (FB1) and B2 (FB2) during industrial dry-milling in two lots from 2014 (n=120) and 2015 (n=120) of non-transgenic corn and their fractions (germ, pericarp, endosperm, cornmeal and grits), collected from one of the major Brazilian milling industries. Fumonisins were concentrated in the germ and pericarp at a rate of 322% and 188% (lot 1) and 311% and 263% (lot 2), respectively. In the endosperm, cornmeal and grits fumonisin levels decreased from 60 to 95%. Fumonisin levels in cornmeal and grits were below the maximum limit tolerated by the European Commission. Therefore, corn industrial dry-milling can contribute to reducing fumonisin levels in corn products intended for human consumption.

Effect of fungicide on Fusarium verticillioides mycelial morphology and fumonisin B1 production.

The effect of fludioxonil + metalaxyl-M on the mycelial morphology, sporulation and fumonisin B 1 production by Fusarium verticillioides 103 F was evaluated. Scanning electron microscopy analysis showed that the fungicide caused inhibition of hyphal growth and defects on hyphae morphology such as cell wall disruption, withered hyphae, and excessive septation. In addition, extracellular material around the hyphae was rarely observed in the presence of fludioxonil + metalaxyl-M. While promoting the reduction of mycelial growth, the fungicide increased sporulation of F. verticillioides compared to the control, and the highest production occurred on the 14 (th) day in the treatments and on the 10 (th) day in the control cultures. Fumonisin B 1 production in the culture media containing the fungicide (treatment) was detected from the 7 (th) day incubation, whereas in cultures without fungicide (control) it was detected on the 10 (th) day. The highest fumonisin B 1 production occurred on the 14 (th) day, both for the control and for the treatment. Fludioxonil + metalaxyl - M can interfere in F. verticillioides mycelial morphology and sporulation and increase fumonisin B 1 levels. These data indicate the importance of understanding the effects of fungicide to minimize the occurrence of toxigenic fungi and fumonisins.

Effect of fungicide on Fusarium verticillioides mycelial morphology and fumonisin B1 production

The effect of fludioxonil + metalaxyl-M on the mycelial morphology, sporulation and fumonisin B1 production by Fusarium verticillioides 103 F was evaluated. Scanning electron microscopy analysis showed that the fungicide caused inhibition of hyphal growth and defects on hyphae morphology such as cell wall disruption, withered hyphae, and excessive septation. In addition, extracellular material around the hyphae was rarely observed in the presence of fludioxonil + metalaxyl-M. While promoting the reduction of mycelial growth, the fungicide increased sporulation of F. verticillioides compared to the control, and the highest production occurred on the 14th day in the treatments and on the 10th day in the control cultures. Fumonisin B1 production in the culture media containing the fungicide (treatment) was detected from the 7th day incubation, whereas in cultures without fungicide (control) it was detected on the 10th day. The highest fumonisin B1 production occurred on the 14th day, both for the control and for the treatment. Fludioxonil + metalaxyl - M can interfere in F. verticillioides mycelial morphology and sporulation and increase fumonisin B1 levels. These data indicate the importance of understanding the effects of fungicide to minimize the occurrence of toxigenic fungi and fumonisins.

Fusarium verticillioides: evaluation of fumonisin production and effect of fungicides on in vitro inhibition of mycelial growth.

The objectives of this study were to evaluate the fumonisin production by 16 F. verticillioides strains on corn cultures and the effect of quintozene and fludioxonil + metalaxyl-M fungicides on "in vitro" mycelial growth on agar. In addition, the effect of fludioxonil + metalaxyl-M on fumonisin production in defined liquid culture medium was analyzed. Fumonisin B(1) levels on corn cultures ranged from 2.41 to 3996.36 µg/g and the F. verticillioides 103F strain produced the highest level (3996.36 ± 390.49 µg/g, P < 0.05). F. verticillioides strains were inoculated in potato dextrose agar with the addition of quintozene (75 to 9,375 µg/ml) and fludioxonil + metalaxyl-M (1.5 + 0.6 to 187.5 + 75 µg/ml) in order to evaluate the effect of these fungicides on "in vitro" mycelial growth. The F. verticillioides strains showed great variability concerning ED(50) values, which were below the recommended application dose for quintozene, but above that for fludioxonil + metalaxyl-M. Moreover, fungicide addition to the culture medium increased mean FB(1) levels compared to the control, suggesting the importance of focusing on the effect of fungicides on mycotoxin production as well as on the phytopathogen control.

Mycotoxicological quality evaluation of corn samples used by processing industries in the Northern region of Paraná State, Brazil.

Based on fungal and fumonisin contamination of 870 freshly harvested samples, the quality of corn used by processing industries in the Northern region of Parana State, Brazil (2003 and 2004 crop-year) was evaluated. Sampling was carried out for each crop at two points in the production chain, i.e. at reception by the processors and at the pre-drying step. Corn samples were more frequently contaminated with Fusarium sp. (100%) and Penicillium sp. (84.1-95.3%) than Aspergillus sp. (5.6-19.8%). Fumonisin B(1) (FB(1)) was detected in all samples from the two points in both crop-years. FB(1) levels ranged 0.02-11.83 microg g(-1) in the reception and 0.02-10.98 microg g(-1) in the pre-drying samples of the 2003 crop. Samples from the 2004 crop showed FB(1) levels ranging 0.03-12.04 microg g(-1) in the reception and 0.06-7.74 microg g(-1) in the pre-drying samples. FB(2) levels ranged 0.02-5.25 microg g(-1) in the reception and 0.01-7.89 microg g(-1) in the pre-drying samples (2003 crop-year). In samples from the 2004 crop, FB(2) levels ranged 0.02-6.12 microg g(-1) in the reception and 0.05-3.47 microg g(-1) in the pre-drying samples. Low fumonisin levels were detected in most corn samples used by processors in the Northern region of Parana State, showing a decreasing trend in fumonisin contamination over the years.

Fumonisins in corn: correlation with Fusarium sp. count, damaged kernels, protein and lipid content

A contaminação natural por fungos e fumonisinas foi avaliada em 109 amostras de milho recém-colhido do Estado do Paraná e correlacionada com grãos ardidos (%). Além disso, grãos sadios e ardidos de 24 amostras de milho foram selecionados a fim de comparar o perfil da microbiota fúngica e níveis de fumonisinas. A correlação entre os teores de proteínas/lipídios e os níveis de fumonisinas também foi analisada nos 15 híbridos de milho mais freqüentemente cultivados no Estado do Paraná. A contagem total de fungos em 109 amostras de milho recém-colhido variou de 1,9x104 a 3,5x106 UFC/g, Fusarium sp. de 1,0x103 a 2,2x106 UFC/g e, níveis de fumonisinas de 0,13 a 20,38 µg/g. A contagem total de fungos/Fusarium spp. e níveis de fumonisinas apresentaram correlação positiva (p<0,05). Adicionalmente, houve uma correlação positiva entre grãos ardidos (%) e a contagem total de fungos/ Fusarium spp. (p < 0,05). Os níveis de fumonisinas nos grãos sadios variaram de 0,57 a 20,38 µg/g, enquanto que nos grãos ardidos variaram de 68,96 a 336,38 µg/g. Não foi observada correlação significativa entre os níveis de fumonisinas e os teores de proteínas/lipídios. Esses resultados ratificam a importância do monitoramento constante da contaminação por fungos toxigênicos e fumonisinas em milho e derivados a fim de garantir a qualidade e segurança dos produtos e minimizar o risco potencial à saúde humana e animal.