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.

Comparison of thin-layer chromatography, spectrofluorimetry and bright greenish-yellow fluorescence test for aflatoxin detection in corn

In this study the bright greenish-yellow fluorescence test, widely used by the corn milling industry, was compared to the thin-layer chromatography (TLC) and spectrofluorimetry methods for aflatoxin detection in 40 corn samples naturally contaminated by the Aspergillus section Flavi. According to the corn processing industry criteria, all the samples were adequate for human and animal consumption by the bright greenish-yellow fluorescence test, but TLC and spectrofluorimetry analysis detected aflatoxins above the maximum tolerated limit (20 µg/kg) in 7 and 8 samples, respectively. Aflatoxins were detected in 16 (40 percent) corn samples by TLC, with levels ranging from 4.0 to 54.0 µg/kg (mean 19.97 ± 15.97 µg/kg), and in 25 (62.5 percent) samples by spectrofluorimetry, with levels ranging from 1.0 to 58.66 µg/kg (mean 17.14 ± 17.81 µg/kg). The results indicated a good correlation (ρ = 0.97) between TLC and spectrofluorimetry for aflatoxin determination in naturally contaminated corn. The bright greenish-yellow fluorescence test was simple and quick, but it showed 20 percent false-negative results, suggesting its use only as screening method for detecting the suspected lots of grains that should be tested further for aflatoxin by more sensitive methods.

Neste trabalho a contagem de fluorescência luminosa amarelo-esverdeada, amplamente utilizada pela indústria de processamento de milho, foi comparada à cromatografia em camada delgada (CCD) e espectrofluorimetria para detecção de aflatoxinas em 40 amostras de milho naturalmente contaminadas por Aspergillus section Flavi. De acordo com os critérios da indústria processadora de milho, todas as amostras estavam adequadas para o consumo humano e animal pela contagem de fluorescência luminosa amarelo-esverdeada (CFLAE), porém as análises por CCD e espectrofluorimetria detectaram aflatoxinas acima do limite máximo tolerado (20 µg/kg) em 7 e 8 amostras, respectivamente. As aflatoxinas foram detectadas em 16 (40 por cento) amostras por CCD, com níveis variando de 4,0 a 54,0 µg/kg (média 19,97 ± 15,97 µg/kg) e, em 25 (62,5 por cento) amostras por espectrofluorimetria, com níveis variando de 1,0 a 58,66 mg/kg (média 17,14 ± 17,81 µg/kg). Os resultados indicaram uma boa correlação (ρ=0,97) entre CCD e espectrofluorimetria para detecção de aflatoxinas em amostras de milho naturalmente contaminadas. A CFLAE, apesar da simplicidade e rapidez, apresentou 20 por cento de resultados falso-negativos, sugerindo seu uso apenas como método de triagem para detecção de lotes de grão suspeitos de contaminação que devem ser avaliados posteriormente por métodos mais sensíveis.