Mycoflora and aflatoxin/fumonisin production by fungal isolates from freshly harvested corn hybrids

Abstract

The mycoflora of 3 hybrids of freshly harvested corn grains collected from three regions of the state of São Paulo, Brazil (Assis, Capão Bonito and Ribeirão Preto) was investigated. A total of 66 samples were analyzed focusing on the influence of abiotic factors (moisture content, water activity, temperature and rainfall) on both the prevalence of Aspergillus flavus and Fusarium moniliforme, and the ability of these genera isolates to produce aflatoxins and fumonisins, respectively. In the three surveyed regions, the fungal population comprised mainly Fusarium spp., Penicillium spp., Aspergillus spp. and 2 others filamentous fungal genera, which were isolated from corn kernels showing water activity of 0.30 to 0.99 and moisture content of 5.0% to 20.2%. Among the genera Fusarium and Aspergillus, the most frequent species were F. moniliforme and A. flavus, respectively. Concerning the toxigenic potential of F. moniliforme, all isolated strains (40) produced fumonisins at 20 µg/g to 2168 µg/g (FB 1 ) and/or 10 µg/g to 380 µg/g (FB 2 ). From the 10 A. flavus isolates, 6 strains (60.0%) produced aflatoxins at 615 µg/kg to 30.750 µg/kg (AFB 1 ) and/or 11 µg/kg to 22 µg/kg (AFB 2 ).

Fusarium verticillioides strains isolated from corn feed: characterization by fumonisin production and RAPD fingerprinting

“…All the strains produced FB 1 and FB 2 with levels ranging from 2.41 to 3996.36 µg/g and from 1.18 to 1209.91 µg/g, respectively ( Table 2). The FB 1 levels were similar to those found by Hinojo et al (2004) but higher than those reported by Almeida et al (2000). Hinojo et al (2004) reported FB 1 levels ranging from 56 to 4775 µg/g in cultures of 13 F. verticillioides isolates from corn.…”

Mycotoxin research in Brazil: the last decade in review

“…In 66 samples of three hybrids of freshly harvested corn from three regions of the state of São Paulo (1995 crop), the fungal population was also mainly composed of Fusarium spp., Penicillium spp., Aspergillus spp. and two other filamentous fungal genera, which were isolated from corn with aw of 0.30 to 0.99 and moisture content of 5 to 20% (1). The most frequent species of the genera Fusarium and Aspergillus were F. moniliforme and A. flavus.…”

“…All cultures were toxigenic, producing AFB 1 , AFB 2 , AFG 1 and AFG 2 . A. flavus was the second most frequent, 22% of which was toxigenic, with the production of AFB 1 or AFB 1 and AFG 1 .…”

Estudo sobre a ocorrência de fungos e aflatoxina B1 na dieta de bovinos leiteiros em São Paulo

“…Em estudo do perfil da micobiota em grãos de milho recém-colhidos em diferentes regiões do Brasil, Rocha et al (2009) isolaram Aspergillus spp como o segundo gênero em frequência no estado de Mato Grosso (14,0%) e estado da Bahia (12,6%). Outros trabalhos também têm verificado a presença de Aspergillus como parte da biota de grãos de milho recém-colhidos no Brasil, sendo superado em termos de frequência de isolamentos pelos fungos Fusarium e Penicillium (Pozzi et al 1995, Almeida et al 2000.…”

“…em grãos de milho e sorgo armazenados em galpões durante período de 12 meses e aumento dos isolamentos de fungos do gênero Aspergillus spp foi observado por Pozzi et al (1995) e Silva et al (2000), respectivamente. Vários estudos realizados com amostras de grãos de milho e sorgo recém colhidos e armazenado no Brasil identificam a espécie A. flavus como a mais isolada (Pozzi et al 1995, Almeida et al 2000, Rocha et al 2009, Reis et al 2010). Em ingredientes de ração destinados a bovinos leiteiros a espécie A. flavus foi identificada como a espécie predominante em 58% (n=90) das amostras analisadas, cepas do fungo (20%) foram capazes de produzir AFB 1 in vitro.…”